Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
Clin Genet ; 78(5): 457-63, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20507346

RESUMEN

The prevalence of germline mutations in MEN1, AIP, PRKAR1A, CDKN1B and CDKN2CI is unknown among pediatric patients with pituitary adenomas (PA). In this study, we screened children with PA for mutations in these genes; somatic GNAS mutations were also studied in a limited number of growth hormone (GH) or prolactin (PRL)-secreting PA. We studied 74 and 6 patients with either isolated Cushing disease (CD) or GH- or PRL-secreting PA, respectively. We also screened four pediatric patients with CD, and four with GH/PRL-secreting tumors who had some syndromic features. There was one AIP mutation (p.Lys103Arg) among 74 CD patients. Two MEN1 mutations that occurred in patients with recurrent or difficult-to-treat disease were found among patients with CD. There was one MEN1 and three AIP mutations (p.Gln307ProfsX104, p.Pro114fsX, p.Lys241X) among pediatric patients with isolated GH- or PRL-secreting PA and one additional MEN1 mutation in a patient with positive family history. There were no mutations in the PRKAR1A, CDKN1B, CDKN2C or GNAS genes. Thus, germline AIP or MEN1 gene mutations are frequent among pediatric patients with GH- or PRL-secreting PA but are significantly rarer in pediatric CD; PRKAR1A mutations are not present in PA outside of Carney complex.


Asunto(s)
Péptidos y Proteínas de Señalización Intracelular/genética , Neoplasia Endocrina Múltiple Tipo 1/genética , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/genética , Neoplasias Hipofisarias/genética , Adolescente , Niño , Cromograninas , Subunidad RIalfa de la Proteína Quinasa Dependiente de AMP Cíclico/genética , Inhibidor p18 de las Quinasas Dependientes de la Ciclina/genética , Inhibidor p27 de las Quinasas Dependientes de la Ciclina , Femenino , Subunidades alfa de la Proteína de Unión al GTP Gs/genética , Mutación de Línea Germinal , Humanos , Masculino , Linaje , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/diagnóstico , Neoplasias Hipofisarias/diagnóstico
2.
Clin Genet ; 75(4): 354-63, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19389109

RESUMEN

Mutations in the gene encoding subunit B of the mitochondrial enzyme succinate dehydrogenase (SDHB) are inherited in an autosomal dominant manner and are associated with hereditary paraganglioma (PGL) and pheochromocytoma. The phenotype of patients with SDHB point mutations has been previously described. However, the phenotype and penetrance of gross SDHB deletions have not been well characterized as they are rarely described. The objective was to describe the phenotype and estimate the penetrance of an exon 1 large SDHB deletion in one kindred. A retrospective and prospective study of 41 relatives across five generations was carried out. The main outcome measures were genetic testing, clinical presentations, plasma catecholamines and their O-methylated metabolites. Of the 41 mutation carriers identified, 11 were diagnosed with PGL, 12 were found to be healthy carriers after evaluation, and 18 were reportedly healthy based on family history accounts. The penetrance of PGL related to the exon 1 large SDHB deletion in this family was estimated to be 35% by age 40. Variable expressivity of the phenotype associated with a large exon 1 SDHB deletion was observed, including low penetrance, diverse primary PGL tumor locations, and malignant potential.


Asunto(s)
Paraganglioma/genética , Penetrancia , Eliminación de Secuencia , Succinato Deshidrogenasa/genética , Adulto , Exones , Salud de la Familia , Femenino , Humanos , Masculino , Paraganglioma/patología , Linaje , Fenotipo , Subunidades de Proteína/genética
3.
Clin Genet ; 67(1): 98-101, 2005 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-15617555

RESUMEN

Congenital generalized Lipodystrophy (BSCL) or Berardinelli-Seip syndrome (Mendelian inheritance in man, catalog no. 269700) is a rare autosomal recessive syndrome characterized by paucity of body fat since birth and insulin resistance. The pathophysiology of this condition is unclear, but defects in insulin function and impaired adipogenesis have been described as important factors in the etiology of the disease. Recently, two gene loci have been identified to harbor the mutations causing this disorder: BSCL1 mapped to human chromosome 9q34 (1, 2) and BSCL2 mapped to human chromosome 11q13 (1, 3). This report describes the natural history of the disease in two siblings (female and male) of Lebanese origin who have mutations in the BSCL2 locus (669delGTATC).


Asunto(s)
Lipodistrofia/genética , Niño , Progresión de la Enfermedad , Salud de la Familia , Femenino , Subunidades gamma de la Proteína de Unión al GTP/genética , Humanos , Lipodistrofia/congénito , Lipodistrofia/patología , Masculino , Eliminación de Secuencia , Factores Sexuales , Hermanos
4.
Br J Cancer ; 80(11): 1682-8, 1999 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10468283

RESUMEN

Prepubertal exposure to a pharmacological dose (500 mg kg(-1)) of the phyto-oestrogen genistein can reduce the incidence and multiplicity of carcinogen-induced mammary tumours in rats. However, such an exposure also disrupts the function of the hypothalamic-pituitary-gonadal axis, making it unsuitable for breast cancer prevention. We studied whether prepubertal exposure to genistein at a total body dose broadly comparable to the level typical of Oriental countries, approximately 1 mg kg(-1) body weight, affects mammary tumorigenesis. We also studied whether prepubertal exposure to zearalenone, a major source for phyto-oestrogens in the USA, influences breast cancer risk. Prepubertal rats were treated between postnatal days 7 and 20, with 20 microg (approximately 1 mg kg(-1) body weight) of either genistein or zearalenone. Zearalenone exposure significantly reduced both the incidence and multiplicity of mammary tumours induced by 7,12-dimethylbenz(a)anthracene (DMBA). Genistein exposure significantly reduced tumour multiplicity, but not tumour incidence, when compared with vehicle-treated animals. Furthermore, 60% of the tumours in the genistein group were not malignant, while all the tumours analysed for histopathology in the vehicle and zearalenone groups were adenocarcinomas. A higher number of differentiated alveolar buds, and lower number of terminal ducts, were present in the DMBA-treated mammary glands of the phyto-oestrogen exposed rats. The concentration of oestrogen receptor (ER) binding sites after the DMBA treatment was low in the mammary glands of all groups but a significantly higher proportion of the glands in the zearalenone exposed rats were ER-positive (i.e. ER levels > or = 5 fmol mg(-1) protein) than the glands of the vehicle controls. Our data suggest that a prepubertal exposure to a low dose of either zearalenone or genistein may protect the mammary gland from carcinogen-induced malignant transformation, possibly by increasing differentiation of the mammary epithelial tree.


Asunto(s)
Anticarcinógenos/farmacología , Genisteína/farmacología , Glándulas Mamarias Animales/efectos de los fármacos , Neoplasias Mamarias Experimentales/prevención & control , Maduración Sexual , Zearalenona/farmacología , 9,10-Dimetil-1,2-benzantraceno , Animales , División Celular/efectos de los fármacos , Femenino , Glándulas Mamarias Animales/citología , Glándulas Mamarias Animales/fisiología , Neoplasias Mamarias Experimentales/inducido químicamente , Neoplasias Mamarias Experimentales/patología , Ratas , Ratas Sprague-Dawley , Receptores de Estrógenos/metabolismo , Factores de Tiempo , Aumento de Peso/efectos de los fármacos
5.
Clin Dysmorphol ; 8(3): 219-21, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10457859

RESUMEN

The acronym SHORT was first used by Gorlin et al. (1975) and Sensenbrenner et al. (1975) to define a recognizable pattern of features, consisting of Short Stature, Hyperextensibility of joints and/or inguinal Hernia, Ocular depression, Rieger anomaly, and Teething delay. Other features characteristic of the syndrome included intrauterine growth retardation (IUGR), slow weight gain, frequent illness, triangular face, anteverted ears, telecanthus, deeply set eyes, wide nasal bridge, hypoplastic alae nasi, chin dimple, micrognathia, clinodactyly, partial lipodystrophy, hearing loss, functional heart murmur, delayed bone age, delayed speech, normal intellect, glucose intolerance, and insulinopenic diabetes. To our knowledge 19 cases of SHORT syndrome have been reported (Gorlin et al., 1975; Sensenbrenner et al., 1975; Aarskog et al., 1983; Toriello et al., 1985; Lipson et al., 1989; Schwingshandl et al., 1993; Verge et al., 1994; Bankier et al., 1985; Brodsky et al., 1996; Sorge et al., 1996; Haan and Morris, 1998). We report the twentieth patient diagnosed with SHORT syndrome who presented with growth retardation, sensorineural hearing loss, and minor dysmorphic features, consistent with the phenotype described for this syndrome.


Asunto(s)
Anomalías Múltiples/patología , Estatura , Discapacidades del Desarrollo , Anomalías del Ojo/patología , Femenino , Hernia Inguinal/patología , Humanos , Lactante , Articulaciones/fisiopatología , Síndrome
6.
Oncol Rep ; 6(5): 1089-95, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10425307

RESUMEN

A high estrogenic environment in utero may increase subsequent breast cancer risk. It was therefore determined whether a maternal exposure during pregnancy to the phytoestrogen genistein or zearalenone, both of which exhibit estrogenic activities in vitro and in vivo, alters breast cancer risk among female offspring. Pregnant rat dams were treated daily with subcutaneous injections of 20, 100 or 300 microgram genistein, 20 microgram zearalenone, or vehicle between days 15 and 20 of gestation. The offspring were given 7, 12-dimethylbenz(a)anthracene (DMBA) at the age of 2 months to induce mammary tumors. The results indicate that in utero exposure to genistein, but not to zearalenone, dose-dependently increased the incidence of DMBA-induced mammary tumors, when compared with the controls. Tumor growth characteristics were not altered. Prior to the carcinogen administration, the number of estrogen receptor (ER) binding sites, determined using a ligand binding assay, were significantly elevated in the mammary glands of genistein offspring. In contrast, the mammary protein kinase C (PKC) activity was significantly reduced in the genistein offspring. Our results suggest that a maternal exposure to subcutaneous administration of genistein can increase mammary tumorigenesis in the offspring, mimicking the effects of in utero estrogenic exposures. Further, increased ER protein levels and reduced PKC activity in the mammary gland may be involved in increasing susceptibility to carcinogen-induced mammary tumorigenesis in rats exposed to genistein in utero.


Asunto(s)
Inhibidores Enzimáticos/toxicidad , Genisteína/toxicidad , Neoplasias Mamarias Animales/inducido químicamente , Exposición Materna , Zearalenona/toxicidad , 9,10-Dimetil-1,2-benzantraceno/toxicidad , Animales , Carcinógenos/toxicidad , Antagonistas de Estrógenos/toxicidad , Femenino , Neoplasias Mamarias Animales/congénito , Embarazo , Ratas , Ratas Sprague-Dawley
7.
J Nutr ; 128(12): 2505-11, 1998 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9868200

RESUMEN

Populations in Western countries consume an excess of polyunsaturated fatty acids (PUFA), even during pregnancy. Since (n-6) PUFA is critical for brain development, we studied whether a high maternal consumption of this fatty acid alters offsprings' affective-like behaviors and (n-6) PUFA-induced protein kinase C (PKC) activity in the brain. Three different strains of pregnant mice were fed isocaloric diets containing either 16% (control) or 43% (high) energy derived from fat high in (n-6) PUFA (corn oil: Balb/c and CD-1 mice, or soybean oil: C3H mice) throughout gestation. From birth onward dams and offspring were fed a nonpurified diet containing 12% energy from a variety of fats. Two- to 12-month-old female and male offspring of dams exposed to a high (n-6) PUFA diet during pregnancy were significantly more active in an open field, more aggressive in the resident-intruder test and spent less time immobile in the swim test than offspring of dams exposed to a control (n-6) PUFA diet. Significantly greater PKC activity in the hypothalamus and moderately less PKC activity in the whole brain (P = 0.10) were seen in the 2-month-old female and male high (n-6) PUFA offspring compared to controls. Our findings indicate that in utero exposure to a high (n-6) PUFA diet subsequently increases locomotor activity and aggression, and reduces immobility in the swim test. The mechanism mediating these effects may be linked to an increased PKC activity in the hypothalamus.


Asunto(s)
Agresión/efectos de los fármacos , Conducta Animal/efectos de los fármacos , Encéfalo/efectos de los fármacos , Grasas de la Dieta/farmacología , Ácidos Grasos Insaturados/farmacología , Proteína Quinasa C/metabolismo , Animales , Encéfalo/enzimología , Grasas de la Dieta/administración & dosificación , Ácidos Grasos Omega-6 , Ácidos Grasos Insaturados/administración & dosificación , Femenino , Feto/efectos de los fármacos , Locomoción/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Tamaño de los Órganos/efectos de los fármacos , Esfuerzo Físico/efectos de los fármacos , Embarazo , Especificidad de la Especie , Natación
8.
Cancer Res ; 58(4): 654-60, 1998 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-9485017

RESUMEN

Previous studies have shown that a diet high in polyunsaturated fatty acids increases mammary tumor incidence in adult and pregnant mice and rats and in the female offspring. The present study investigated whether a high-fat diet alters the number of estrogen receptor (ER) binding sites and protein kinase C (PKC) activity in the mammary gland of these animals. In the female offspring, the effects of maternal exposure to a high-fat diet during pregnancy on development of the mammary epithelial tree were studied also. BALB/c mice were kept on a diet containing either 43% (high-fat) or 16% (low-fat) calories from corn oil, which consists mostly of n-6 polyunsaturated fatty acids, for 1 month. In adult female mice, a 6-fold increase in the number of ER binding sites and 2-fold increase in PKC activity were found in the mammary glands of the high-fat mice when compared with the low-fat mice. In pregnant mice, a high-fat diet increased ER binding sites by 61% and PKC activity by 51%. In contrast to adult and pregnant mice, females exposed to a high-fat diet only in utero through their pregnant mother exhibited a significantly reduced number of mammary ER binding sites by age 45 days (78% decrease) and a reduction in PKC activity by ages 30 and 100 days (44 and 20% decrease, respectively). The mammary epithelial tree of the high-fat offspring contained more terminal end buds and was less differentiated than that of the low-fat offspring. These findings show that consumption of a high-fat diet increases ER and PKC in the adult and pregnant mouse mammary gland, perhaps contributing to the fat-induced promotion of mammary tumorigenesis. In contrast, reduced ER and PKC following a high-fat exposure in utero may be associated with increased susceptibility to carcinogenesis, possibly due to an increased number of terminal end buds that are the sites of neoplastic transformation in the mammary gland.


Asunto(s)
Grasas de la Dieta , Glándulas Mamarias Animales/crecimiento & desarrollo , Glándulas Mamarias Animales/metabolismo , Preñez , Proteína Quinasa C/metabolismo , Receptores de Estrógenos/metabolismo , Animales , Peso Corporal , Femenino , Glándulas Mamarias Animales/embriología , Ratones , Embarazo , Resultado del Embarazo , Maduración Sexual
9.
Pharmacol Biochem Behav ; 58(3): 785-91, 1997 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9329073

RESUMEN

The biological mechanisms behind ethanol-induced aggression are not known. Because gonadal hormones are linked both to aggression and ethanol, the present study examined relationships among the levels of serum estradiol (E2), testosterone (T), and aggressive behavior in ethanol-treated male mice. We found that among group-housed male mice, serum E2 levels were significantly elevated 30 min after a single injection of 0.6 g/kg ethanol. Serum T levels showed a nonsignificant decrease by ethanol. The E2/T ratio, an index of aromatization of T to E2, was significantly higher in the ethanol-treated animals when compared with the vehicle-treated animals. We also determined aggressive behavior in the resident-intruder test among isolated male mice at baseline (after a vehicle), and after an injection of 0.6 g/kg ethanol. The mice were grouped accordingly to those that increased, decreased, or remained nonaggressive in response to ethanol administration. We found that at baseline, neither serum T or E2 levels, nor E2/T ratio differed significantly between the increased or reduced aggressor mice. In contrast to the increase in serum E2 levels seen in the nonaggressive mice, ethanol significantly reduced circulating E2 levels, but did not affect aromatization of E2 from T in the mice that became aggressive following an ethanol injection. These data suggest that mice who exhibit a paradoxical decrease in serum E2 levels by ethanol may be particularly prone to ethanol-induced aggression.


Asunto(s)
Agresión/fisiología , Depresores del Sistema Nervioso Central/farmacología , Estradiol/sangre , Etanol/farmacología , Agresión/efectos de los fármacos , Animales , Masculino , Ratones , Testosterona/sangre
10.
Proc Natl Acad Sci U S A ; 94(17): 9372-7, 1997 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-9256489

RESUMEN

We hypothesized that feeding pregnant rats with a high-fat diet would increase both circulating 17beta-estradiol (E2) levels in the dams and the risk of developing carcinogen-induced mammary tumors among their female offspring. Pregnant rats were fed isocaloric diets containing 12% or 16% (low fat) or 43% or 46% (high fat) of calories from corn oil, which primarily contains the n - 6 polyunsaturated fatty acid (PUFA) linoleic acid, throughout pregnancy. The plasma concentrations of E2 were significantly higher in pregnant females fed a high n - 6 PUFA diet. The female offspring of these rats were fed with a laboratory chow from birth onward, and when exposed to 7,12-dimethylbenz(a)anthracene had a significantly higher mammary tumor incidence (60% vs. 30%) and shorter latency for tumor appearance (11.4 +/- 0.5 weeks vs. 14.2 +/- 0.6 weeks) than the offspring of the low-fat mothers. The high-fat offspring also had puberty onset at a younger age, and their mammary glands contained significantly higher numbers of the epithelial structures that are the targets for malignant transformation. Comparable changes in puberty onset, mammary gland morphology, and tumor incidence were observed in the offspring of rats treated daily with 20 ng of E2 during pregnancy. These data, if extrapolated to humans, may explain the link among diet, early puberty onset, mammary parenchymal patterns, and breast cancer risk, and indicate that an in utero exposure to a diet high in n - 6 PUFA and/or estrogenic stimuli may be critical for affecting breast cancer risk.


Asunto(s)
Grasas de la Dieta/administración & dosificación , Glándulas Mamarias Animales/fisiología , Neoplasias Mamarias Animales/etiología , Preñez/fisiología , Efectos Tardíos de la Exposición Prenatal , Maduración Sexual , Animales , Ácidos Grasos Insaturados/administración & dosificación , Femenino , Glándulas Mamarias Animales/patología , Embarazo , Ratas , Ratas Sprague-Dawley
11.
Physiol Behav ; 62(1): 207-11, 1997 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9226364

RESUMEN

Estrogen acting during the critical developmental period has been postulated to defeminize and possibly masculinize male sexual behavior. Transforming growth factor alpha (TGF alpha) also may be involved, because this growth factor, at least partly, mediates the mitotic effects of estrogen on target tissues. Male transgenic mice overexpressing TGF alpha have elevated serum estradiol (E2) levels and they exhibit feminization of many nonreproductive actions, suggesting that either TGF alpha and/or E2, or both, participate in the control of some nonreproductive behavior. Male and female CD-1 mice were treated with 4 microg of recombinant human TGF alpha or 2-4 microg E2 during the first 3 days of life. Although early TGF alpha treatment accelerates physical development and influences the growth of the uterus and mammary gland, it failed to have any effect on behavior, either in male or female mice. Early E2 treatment significantly lengthened immobility time in the swim test and reduced voluntary alcohol intake among the male mice. No changes in locomotor activity or aggressive behavior were noted. The expression of TGF alpha mRNA in the brainstem of adult male mice was not altered following neonatal TGF alpha or E2 treatment. However, neonatal exposure to TGF alpha caused a moderate elevation in TGF alpha mRNA expression in the female brainstem. Our results indicate that in male, but not in female mice, an excess of E2 during early life affects some nonreproductive behavior. Furthermore, early treatment with recombinant human TGF alpha does not alter nonreproductive behavior in mice.


Asunto(s)
Conducta Animal/efectos de los fármacos , Conducta Sexual Animal/efectos de los fármacos , Factor de Crecimiento Transformador alfa/farmacología , Animales , Animales Recién Nacidos , Período Crítico Psicológico , Estradiol/farmacología , Femenino , Masculino , Ratones , Embarazo , Proteínas Recombinantes/farmacología , Diferenciación Sexual/efectos de los fármacos , Maduración Sexual/efectos de los fármacos
12.
J Cell Physiol ; 170(3): 279-89, 1997 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9066785

RESUMEN

High fetal/early postnatal levels of estrogen increase breast cancer risk, but the mechanisms remain unknown. Growth factors, such as transforming growth factor alpha (TGF alpha), may participate as secondary modifiers in this process. We characterized a modulatory role of early postnatal exposure to 17 beta-estradiol (E2) on the developing mammary gland morphology by treating intact female CD-1 mice with physiological doses of E2 (2-4 micrograms), human recombinant TGF alpha (4 micrograms), or an estrogen receptor (ER) antagonist ICI 182,780 (20 micrograms) during postnatal days 1-3. Early postnatal exposure of E2 stimulated mammary ductal growth by days 25 and 35, but by day 50 this was inhibited. The level of differentiation from terminal end buds (TEBs) to the lobulo-alveolar units (LAUs) also was reduced by day 50. The number of TEBs was increased throughout most of the development in the female mice exposed to E2 during early life. An exposure to TGF alpha or ICI 182,780 between postnatal days 1 and 3 stimulated ductal growth, formation of TEBs, and the differentiation of mammary epithelial structures. ICI 182,80 treatment also caused hyperplastic lobular-like structures in 54-day-old females. Thus, neonatal exposure to TGF alpha and ICI 182,780 induced both similar (increase in TEBs) and different (increase/decrease in lobulo-alveolar differentiation) developmental changes in the mouse mammary gland, when compared with an exposure to E2. A unique feature of the postnatal E2 treatment was that it inhibited ductal migration by days 50-54. Our data suggest than an exposure to E2 on postnatal days 1-3, possibly combined with secondary epigenetic alterations, leads to various changes within the developing mammary tree. These changes may be potential prerequisites for mammary tumorigenesis.


Asunto(s)
Estradiol/análogos & derivados , Estradiol/farmacología , Antagonistas de Estrógenos/farmacología , Glándulas Mamarias Animales/efectos de los fármacos , Factor de Crecimiento Transformador alfa/farmacología , Tejido Adiposo/citología , Tejido Adiposo/efectos de los fármacos , Tejido Adiposo/crecimiento & desarrollo , Animales , Animales Recién Nacidos , Tampones (Química) , Células Epiteliales , Epitelio/efectos de los fármacos , Epitelio/crecimiento & desarrollo , Femenino , Fulvestrant , Humanos , Glándulas Mamarias Animales/crecimiento & desarrollo , Ratones , Ratones Endogámicos , Aceites/farmacología , Fosfatos/farmacología , Embarazo , Receptores de Estrógenos/antagonistas & inhibidores
13.
J Natl Cancer Inst ; 88(24): 1821-7, 1996 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-8961971

RESUMEN

BACKGROUND: Women who took the synthetic estrogen diethylstilbestrol during pregnancy exhibit an elevated risk of breast cancer, whereas those who suffered from preeclampsia, which is associated with low circulating pregnancy estrogens, exhibit a reduced risk. Since a high-fat diet may increase circulating estrogen levels and possibly breast cancer risk, dietary factors during pregnancy could influence the risk of developing this disease. PURPOSE: We tested the hypothesis that consumption of a high-fat diet during pregnancy increases carcinogen-induced mammary tumor incidence in rats. METHODS: Pregnant or virgin female Sprague-Dawley rats that had been previously treated with 10 mg 7, 12-dimethylbenz[a]anthracene (DMBA) by oral gavage when 55 days old were assigned to one of two isocaloric diets containing either 16% calories from fat (low-fat) or 43% calories from fat (high-fat) for the length of pregnancy or for the equivalent time of approximately 21 days. There were 20 pregnant and 10 nonpregnant DMBA-treated rats per group. Ten additional pregnant animals (not previously treated with DMBA) per group were used for hormone analysis. The fat source used was corn oil, which is high in n-6 polyunsaturated fatty acids, primarily linoleic acid. The animals were checked for tumors at least once per week by palpation. The tumor size, number, and latency to appearance after carcinogen exposure were recorded. The statistical significance of observed differences was tested by use of appropriate two-sided tests. RESULTS: Female rats on different diets had virtually identical food intakes and weight gains during pregnancy. On gestation day 19, serum estradiol levels were approximately twofold higher in rats fed a high-fat diet than in rats fed a low-fat diet (P < .02). The serum insulin levels and insulin/glucose ratios (an index of insulin resistance) in rats fed the high-fat diet were approximately twofold lower than in rats fed the low-fat diet, but the differences did not reach statistical significance (P < .09 and P < .09, respectively). On week 18 following DMBA administration, the number of rats developing mammary tumors was significantly higher in the group exposed to a high-fat diet (40% of animals) than in the group exposed to a low-fat diet (10% of animals) during pregnancy (P < .05). Tumor multiplicity, latency to tumor appearance, and size of tumors upon first detection were similar among the dietary groups. No intergroup differences in the mammary tumor incidence were noted in virgin animals that were exposed to the high- or low-fat diets for an equivalent period of time. CONCLUSIONS: Our findings indicate that consumption of a diet high in fat (primarily in the form of n-6 polyunsaturated fatty acids) during pregnancy increases the risk of developing carcinogen-induced mammary tumors, possibly by increasing the pregnancy levels of circulating estrogens. IMPLICATIONS: If further studies find that the results from animal model studies are applicable to humans, some human breast cancers may be preventable by dietary manipulations during pregnancy.


Asunto(s)
Grasas de la Dieta/efectos adversos , Ácidos Grasos Insaturados/efectos adversos , Neoplasias Mamarias Experimentales/inducido químicamente , Complicaciones Neoplásicas del Embarazo/inducido químicamente , 9,10-Dimetil-1,2-benzantraceno , Animales , Glucemia/metabolismo , Grasas de la Dieta/administración & dosificación , Ingestión de Energía , Estrógenos/sangre , Ácidos Grasos Insaturados/administración & dosificación , Femenino , Humanos , Insulina/sangre , Neoplasias Mamarias Experimentales/sangre , Embarazo , Complicaciones Neoplásicas del Embarazo/sangre , Ratas , Ratas Sprague-Dawley , Riesgo
14.
J Mol Endocrinol ; 17(1): 79-88, 1996 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8863190

RESUMEN

The pancreatic regenerating (reg) gene is proposed to be involved in pancreatic beta-cell growth. Up- or down-regulation of reg gene expression has been shown to parallel variations in beta-cell mass and function in the adult pancreas. In several species at least two nonallelic reg genes have been identified. In this study we investigated the expression of each individual reg gene (reg-I and reg-II) during embryogenesis in the mouse. Single mouse embryos were harvested at 8.5, 9, 10, and 12 days of development, homogenized and subjected individually to reverse transcription (RT)-PCR, with a single primer pair to amplify both reg-I and -II mRNAs. Southern blot analysis of the RT-PCR products revealed the presence of reg mRNA at day 9 of embryogenesis, just before the beginning of pancreatic organogenesis. Slot-blot analysis with internal oligonucleotide probes that specifically recognize reg-I or -II sequences demonstrated that only reg-I mRNA was present in day 9 and day 10 prepancreatic embryos. Reg-II mRNA was not detected until day 12, a stage corresponding to late organogenesis. RT-PCR for insulin mRNA from the same samples used for the amplification of reg mRNA showed that the earliest insulin expression occurred at day 8.5, and coincided with the onset of reg-I expression. Hybridization with gene-specific oligonucleotide probes revealed that only insulin-II mRNA was detectable at this time. Insulin-I mRNA was not detectable until day 12 and coincided with early reg-II expression. These results suggest that the two nonallelic reg genes and the two insulin genes are expressed differentially during early embryogenesis. Differential expression of reg-I and -II suggests that they may be induced by different and independent stimuli and have distinct functions.


Asunto(s)
Proteínas de Unión al Calcio/genética , Regulación del Desarrollo de la Expresión Génica , Insulina/genética , Proteínas del Tejido Nervioso , Páncreas/metabolismo , Regeneración/genética , Animales , ADN Complementario , Femenino , Litostatina , Ratones , Sondas de Oligonucleótidos , Páncreas/embriología , Embarazo
15.
Mol Cell Endocrinol ; 116(1): 81-7, 1996 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-8822268

RESUMEN

Acute studies of glucose-dependent insulinotropic peptide (GIP) have shown that GIP can synergize with glucose in stimulating insulin secretion both in vivo and in vitro. Here we studied the effects of extended exposure of RIN 1046-38 cells, an insulin-secreting cell line, to GIP and the mechanisms by which GIP synergizes with glucose in stimulating insulin secretion. Incubation of the cells with 100 nM GIP in the presence of glucose for 12 h significantly increased insulin release (287 +/- 31.7 vs. 102 +/- 9.7 ng/mg protein; n = 3), intracellular insulin content (12.8 +/- 0.83 vs. 8.2 +/- 0.52 ng/mg protein; n = 3), and insulin mRNA (approximately 2.7-fold; 24 h incubation) when compared to cells cultured with glucose alone. The insulinotropic effects of GIP on RIN 1046-38 cells were accompanied by an up-regulation of GLUT-1 and hexokinase I mRNA (1.75-fold) compared to non-GIP-treated cells; mRNA levels of GLUT-2 and glucokinase were unchanged by GIP, in the presence or absence of glucose. Our study suggests that the mechanism by which extended exposure of RIN 1046-38 cells to GIP increases glucose-stimulated insulin secretion includes up-regulation of glucose sensing elements.


Asunto(s)
Polipéptido Inhibidor Gástrico/farmacología , Hexoquinasa/metabolismo , Insulina/metabolismo , Proteínas de Transporte de Monosacáridos/metabolismo , Animales , Línea Celular , Expresión Génica/efectos de los fármacos , Glucosa/farmacología , Transportador de Glucosa de Tipo 1 , Transportador de Glucosa de Tipo 2 , Hexoquinasa/genética , Secreción de Insulina , Proteínas de Transporte de Monosacáridos/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas
16.
Endocrinology ; 136(11): 4910-7, 1995 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7588224

RESUMEN

It has been previously demonstrated that the enteric hormone glucagon-like peptide-1 (7-36 amide) (GLP-1) has acute effects on glucose-induced insulin secretion by RIN 1046-38 cells. In this study, we investigated the effects of extended exposure of RIN 1046-38 cells to GLP-1 and examine the mechanism by which GLP-1 synergizes with glucose in stimulating insulin secretion. Compared with cells cultured with glucose alone, incubation of cells with glucose plus 1 or 10 nM GLP-1 for 12 or 24 h significantly increased insulin release by about 3-fold, intracellular insulin content by 1.5-fold, and insulin messenger RNA (mRNA) by almost 2.5-fold. The insulinotropic effects of GLP-1 on RIN 1046-38 cells were accompanied by an up-regulation of both glucose transporter-1 (GLUT-1) and hexokinase I mRNA by about 2-fold. mRNA levels of GLUT-2 and glucokinase, which were low in controls, were unchanged by GLP-1 treatment. Treatment of cells with a transcription inhibitor, actinomycin D, demonstrated that elevated insulin mRNA levels after a GLP-1 exposure are mainly due to stabilization of the mRNA. In contrast, the elevated mRNA levels of GLUT-1 and hexokinase I are the result of increased transcription stimulated by GLP-1 exposure. Actinomycin D blunted the GLP-1 effect on insulin release but did not affect GLP-1 mediated elevation of insulin mRNA. This suggests that actinomycin D inhibits the transcription of the proteins necessary for insulin biosynthesis and insulin release, such as GLUT-1 and hexokinase I. Our study suggests that the mechanisms by which extended exposure of RIN 1046-38 cells to GLP-1 increases glucose-stimulated insulin secretion include significant up-regulation of glucose-sensing elements.


Asunto(s)
Regulación de la Expresión Génica/efectos de los fármacos , Glucagón/farmacología , Insulina/genética , Insulina/metabolismo , Fragmentos de Péptidos/farmacología , Precursores de Proteínas/farmacología , ARN Mensajero/metabolismo , Transcripción Genética/efectos de los fármacos , Animales , Medios de Cultivo Condicionados , Cicloheximida/farmacología , Dactinomicina/farmacología , Estabilidad de Medicamentos , Sinergismo Farmacológico , Péptido 1 Similar al Glucagón , Glucosa/farmacología , Transportador de Glucosa de Tipo 1 , Hexoquinasa/genética , Secreción de Insulina , Insulinoma , Proteínas de Transporte de Monosacáridos/genética , Neoplasias Pancreáticas , Ratas , Células Tumorales Cultivadas
18.
Life Sci ; 55(12): 925-31, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-8057754

RESUMEN

There is an inverse relationship between nicotine and body weight. It has been proposed that this inverse relationship is partially mediated by insulinergic actions, but the effect of nicotine on insulin only has been reported for male rats. The present experiment was designed to examine the effect of nicotine administration on body weight and plasma insulin in female and male rats. In addition, the effects of anesthesia prior to sacrifice on plasma insulin were examined. Nicotine reduced body weight and plasma insulin in female and male rats. In addition, the use of an anesthetic prior to sacrifice was associated with higher plasma insulin levels for male rats. These findings are consistent with the interpretation that insulinergic mechanisms play a role in the nicotine-body weight relationship.


Asunto(s)
Peso Corporal/efectos de los fármacos , Insulina/sangre , Nicotina/toxicidad , Análisis de Varianza , Anestesia/efectos adversos , Animales , Femenino , Bombas de Infusión Implantables , Masculino , Nicotina/administración & dosificación , Pentobarbital , Ratas , Ratas Sprague-Dawley , Factores Sexuales
19.
Brain Res Bull ; 29(2): 129-34, 1992 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1326377

RESUMEN

Four experiments examined the effects of stress on hypothalamic insulin and plasma hormones in rats. Two hours daily of immobilization (IM) stress for 2 and 4 days resulted in an increase in hypothalamic insulin. In contrast, 15 min of daily IM over 13 days or 48 h of continuous signalled shock avoidance did not alter hypothalamic insulin. These findings are interpreted to indicate that changes in hypothalamic insulin are part of the stress response. Possible reasons for the different effects of time and paradigm on the hypothalamic insulin responses to stress are discussed. Plasma insulin and glucose levels were not responsive to any of the stressors. Brief acute stress caused increases in the stress-responsive hormones ACTH, corticosterone, and prolactin, as expected, and these responses attenuated or disappeared with repeated or longer stress exposures.


Asunto(s)
Hipotálamo/metabolismo , Insulina/metabolismo , Estrés Psicológico/metabolismo , Hormona Adrenocorticotrópica/sangre , Animales , Glucemia/metabolismo , Peso Corporal , Corticosterona/sangre , Ingestión de Alimentos , Electrochoque , Hormonas/sangre , Inmovilización , Insulina/sangre , Masculino , Prolactina/sangre , Ratas , Ratas Endogámicas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA