RESUMEN
BACKGROUND/OBJECTIVES: Serum or tissue zinc concentrations are often used to assess body zinc status. However, all of these methods are relatively inaccurate. Thus, we investigated three different kinetic methods for the determination of zinc clearance to establish which of these could detect small changes in the body zinc status of children. SUBJECTS/METHODS: Forty apparently healthy children were studied. Renal handling of zinc was investigated during intravenous zinc administration (0.06537 mg Zn/kg of body weight), both before and after oral zinc supplementation (5 mg Zn/day for 3 months). Three kinetic methods were used to determine zinc clearance: CZn-Formula A and CZn-Formula B were both used to calculate systemic clearance; the first is a general formula and the second is used for the specific analysis of a single-compartment model; CZn-Formula C is widely used in medical practices to analyze kinetic routine. RESULTS: Basal serum zinc values, which were within the reference range for healthy children, increased significantly after oral zinc supplementation. The three formulas used gave different results for zinc clearance both before and after oral zinc supplementation. CZn-Formula B showed a positive correlation with basal serum zinc concentration after oral supplementation (R2=0.1172, P=0.0306). In addition, CZn-Formula B (P=0.0002) was more effective than CZn-Formula A (P=0.6028) and CZn-Formula C (P=0.0732) in detecting small variations in body zinc status. CONCLUSIONS: All three of the formulas used are suitable for studying zinc kinetics; however, CZn-Formula B is particularly effective at detecting small changes in body zinc status in healthy children.
Asunto(s)
Estado Nutricional , Zinc/farmacocinética , Composición Corporal , Niño , Suplementos Dietéticos , Femenino , Humanos , Masculino , Matemática , Tasa de Depuración Metabólica , Zinc/administración & dosificación , Zinc/sangreRESUMEN
A number of commercially available waxes in the form of thin disc samples have been investigated as possible diffraction intensity standards for macromolecular crystallography synchrotron beamlines. Synchrotron X-ray powder diffraction measurements show that beeswax offers the best performance of these waxes owing to its polycrystallinity. Crystallographic lattice parameters and diffraction intensities were examined between 281 and 309 K, and show stable and predictable thermal behaviour. Using an X-ray beam of known incident flux at lambda = 1 A, the diffraction power of two strong Bragg reflections for beeswax were quantified as a function of sample thickness and normalized to 10(10) photons s(-1). To demonstrate its feasibility as a diffraction intensity standard, test measurements were then performed on a new third-generation macromolecular crystallography synchrotron beamline.
Asunto(s)
Cristalografía por Rayos X/normas , Sustancias Macromoleculares/química , Sustancias Macromoleculares/normas , Sincrotrones/normas , Ceras/química , Ceras/normas , Brasil , Cristalografía por Rayos X/métodos , Estudios de Factibilidad , Estándares de Referencia , Refractometría , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Crotoxin, a potent neurotoxin from the venom of the South American rattlesnake Crotalus durissus terrificus, exists as a heterodimer formed between a phospholipase A(2) and a catalytically inactive acidic phospholipase A(2) analogue (crotapotin). Large single crystals of the crotoxin complex and of the isolated subunits have been obtained. The crotoxin complex crystal belongs to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 38.2, b = 68.7, c = 84.2 A, and diffracted to 1.75 A resolution. The crystal of the phospholipase A(2) domain belongs to the hexagonal space group P6(1)22 (or its enantiomorph P6(5)22), with unit-cell parameters a = b = 38.7, c = 286.7 A, and diffracted to 2.6 A resolution. The crotapotin crystal diffracted to 2.3 A resolution; however, the highly diffuse diffraction pattern did not permit unambiguous assignment of the unit-cell parameters.
Asunto(s)
Crotoxina/química , Fosfolipasas A/química , Cristalización , Cristalografía por Rayos X , Dimerización , Fosfolipasas A2 , Conformación ProteicaRESUMEN
PURPOSE: To correlate serum leptin and insulin levels, and the glucosic profile of 21 patients shared in diabetics and non diabetics with Congenital Generalized Lipodystrophy (CGL). METHODS: In a prospective study, were dosed serum leptin level with radioimmunoassay technique, fasting plasma glucose through of the glucoseoxidase-peroxidase reaction, the hemoglobin glycate using the technique microchromatography for ionic exchange resin and insulin through immunoassay system. The fructosamine concentration serum was determinated for reduction nitroblue tetrazolium method. The Student's test was used to compare results between the groups and the correlation [quot ]r[quot ] coefficient to analise the relation among the several variants studied, with significant level of 5% (p < 0.05). All the statistical procedures were performed using the Excel by Microsoft and the Statistic program for Windows by StatSoft, Inc. version 5.1 edition 97. RESULTS: Leptin decreased on the most patients, showing no statistically significant difference between the groups. Also there wasn't difference statistically significant (p = 0.9542) of the insulin's value between diabetics and non diabetics. CONCLUSION: The hyperinsulinism and the hypoleptinemia occurred independently of diabetes in the CGL's patients and this can be due to the natural history of disease, in which the raise insulin levels precede the initial diabetes mellitus and the low leptin levels were related to the lipoatrophy.
Asunto(s)
Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Masculino , Diabetes Mellitus Lipoatrófica/sangre , Hiperinsulinismo/sangre , Leptina/sangre , Lipodistrofia Generalizada Congénita/sangre , Tejido Adiposo/metabolismo , Glucemia , Índice de Masa Corporal , Consanguinidad , Fructosamina/sangre , Hemoglobina Glucada/análisis , Resistencia a la Insulina , Estudios ProspectivosRESUMEN
A novel trypsin inhibitor isolated from seeds of Copaifera langsdorffii was purified to homogeneity and crystallized. Crystals suitable for X-ray analysis were grown using the hanging-drop vapour-diffusion method at 291 K in sodium acetate buffer at pH values near 4.3 using PEG 4000 as precipitant. The crystals presented symmetry compatible with the space group P4(1)2(1)2 or P4(3)2(1)2, with unit-cell parameters a = b = 58.71, c = 93.75 A, and diffracted to 1.83 A resolution at the synchrotron source.
Asunto(s)
Fabaceae/química , Proteínas de Plantas/química , Proteínas de Saccharomyces cerevisiae , Inhibidores de Tripsina/química , Cristalización , Cristalografía por Rayos X , Proteínas de la Membrana , Datos de Secuencia Molecular , Conformación Proteica , Semillas/química , Análisis de Secuencia de Proteína , Homología de Secuencia de Aminoácido , Inhibidores de Tripsina/aislamiento & purificaciónRESUMEN
Hyperzincuria is a common feature in diabetic patients, which is still not understood. Based on the above consideration, the aim of the present study was to investigate the renal handling of zinc in insulin-dependent diabetes mellitus (IDDM) patients. The glomerular filtration rate, urinary zinc excretion, zinc clearance, zinc clearance/creatinine clearance ratio, zinc tubular reabsorption, glycosuria, plasma glucose, C-peptide, glucagon, and cortisol were investigated in 10 normal individuals (Group C1 and Group C2, respectively) and 10 IDDM patients (Group E1: hyperglycemic and glycosuric and Group E2: normoglycemic and aglycosuric) during placebo or venous zinc tolerance test. The results showed that urinary zinc excretion and renal zinc clearance were increased after zinc injection in normal individuals (Group C2) and IDDM patients (Groups E1 and E2) when compared with normal individuals-placebo (Group C1). However, these renal parameters were statistically more significant in the hyperglycemic and glycosuric diabetics (Group E1). Because patients in Group E1 had the lowest plasma C-peptide levels and showed a strong negative correlation between CZn++/Ccr ratio and this hormone, we suggest that in this setting insulin inhibits urinary zinc excretion.
Asunto(s)
Diabetes Mellitus Tipo 1/metabolismo , Riñón/metabolismo , Zinc/metabolismo , Adulto , Glucemia/metabolismo , Péptido C/sangre , Estudios de Casos y Controles , Creatinina/metabolismo , Diabetes Mellitus Tipo 1/orina , Femenino , Tasa de Filtración Glomerular , Glucagón/sangre , Glucosuria/metabolismo , Humanos , Hidrocortisona/sangre , Túbulos Renales/metabolismo , Masculino , Zinc/orinaRESUMEN
Rhodnius haem-binding protein (RHBP) from the bloodsucking insect Rhodnius prolixus, a 15 kDa protein, has been crystallized using polyethylene glycol as a precipitant. X-ray diffraction data have been collected at a synchrotron source. The crystals belong to the space group P4(1(3))2(1)2, with unit-cell parameters a = b = 64.98, c = 210.68 A, and diffract beyond 2.6 A resolution.
Asunto(s)
Proteínas Portadoras/química , Hemoproteínas/química , Proteínas de Insectos/química , Rhodnius/química , Animales , Cristalización , Cristalografía por Rayos X , Proteínas de Unión al Hemo , Peso Molecular , Conformación ProteicaRESUMEN
Zinc has an important role in the control of carbohydrate metabolism, and diabetic patients are at risk for zinc deficiency. However, there are conflicting data concerning nutritional zinc status. In order to investigate this topic, 10 normal and 10 insulin-dependent diabetic patients were studied following venous zinc tolerance test. Our results found no evidence of zinc deficiency or of changes on the kinetic parameters of zinc in patients with insulin-dependent diabetes mellitus following a venous zinc tolerance test.
Asunto(s)
Diabetes Mellitus Tipo 1/metabolismo , Estado Nutricional , Zinc/metabolismo , Adulto , Femenino , Humanos , Masculino , Zinc/sangre , Zinc/deficienciaRESUMEN
Previous in vitro studies have demonstrated zinc (Zn++) inhibition of basal and of potassium (K+) or thyrotropin-releasing hormone (TRH)-stimulated prolactin (PRL) secretion, in a selective, reversible, and dose-dependent manner. Thus, Zn++ may regulate physiologically pituitary PRL secretion. Furthermore, studies with patients with uremia, cirrhosis or prolactinoma, have shown the coexistence of hypozincemia and hyperprolactinemia and zinc supplementation did not correct hyperprolactinemia in these patients. In normal individuals Zn++ administration produced controversial results on PRL secretion. Here, we investigated whether zinc administration affects TRH-stimulated PRL in healthy men. We found that Zn++ administration does not change the TRH-stimulated PRL. Therefore, in normal conditions, Zn++ does not inhibit TRH-stimulated prolactinemia. In addition, we found that acute increases of blood PRL and TRH do not alter blood Zn++ levels.
Asunto(s)
Prolactina/metabolismo , Hormona Liberadora de Tirotropina/farmacología , Zinc/farmacología , Adulto , Humanos , Masculino , Prolactina/sangre , Valores de Referencia , Factores de TiempoAsunto(s)
Glucemia/análisis , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/cirugía , Glucagón/sangre , Insulina/sangre , Trasplante de Páncreas , Anastomosis Quirúrgica , Animales , Supervivencia de Injerto , Masculino , Sistema Porta/cirugía , Ratas , Ratas Wistar , Trasplante IsogénicoRESUMEN
Zinc plays a very important role in animal and human metabolism. Nowadays, it is one of the most extensively studied trace element, since its sphere of action has been demonstrated to be very broad. From the biochemical standpoint, it controls more than 300 different enzymes, many of them involved with intermediary metabolism, DNA and RNA synthesis, gene expression, and immunocompetence. It also plays a significant role in hormonal homeostasis, since it can interact with almost all hormones. Zn2+ is closely related to the thyroid and steroid hormones, insulin, parathormone, and pituitary hormones, particularly prolactin (PRL). Zn2+ can inhibit PRL secretion within a range of physiologically and pharmacologically relevant concentrations. This property has raised the possibility of clinical applications of zinc. In this article, we review the literature on the subject in an attempt to provide a comprehensible general view.
Asunto(s)
Hipófisis/metabolismo , Prolactina/biosíntesis , Zinc/farmacología , Animales , Calcio/metabolismo , Canales de Calcio/efectos de los fármacos , Canales de Calcio/fisiología , Calmodulina/metabolismo , Enzimas/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/genética , Humanos , Técnicas In Vitro , Hipófisis/efectos de los fármacos , Neoplasias Hipofisarias/tratamiento farmacológico , Neoplasias Hipofisarias/patología , Prolactina/metabolismo , Prolactinoma/tratamiento farmacológico , Prolactinoma/patología , Zinc/fisiología , Dedos de Zinc/fisiologíaRESUMEN
PURPOSE: To evaluate the effects of captopril (Cpt).on carbohydrate metabolism and growth hormone (GH) in adults hypertensive obese patients with normal (NGT) or impaired (IGT) glucose tolerance and left ventricular hypertrophy. METHODS: Ten patients (53 +/- 8 years), 8 women and 2 men, white, body mass index (BMI) > or = 26kg/m2, left ventricular mass index (LVMI) > 135g/m2 in man and > 110g/m2 in woman, with diastolic blood pressure (DBP) 95-115mmHg after 3 weeks of placebo, were identified by oral glucose tolerance test (OGTT-75g) as either with NGT or IGT, and treated with Cpt 25mg t.i.d. for 8 weeks. At the 8 weeks, dosage was increased to 50mg b.i.d. if DBP > 90mmHg or the decrease of the DBP < 10%, during the next 8 weeks. OGTT and clonidine tests (0,04mg/kg) with determinations, every 30 minutes of glucose, insulin, and GH during 2 hours, were performed. RESULTS: Cpt lowered SBP and DBP in the NGT group and IGT group. The LVMI and the left ventricular mass (LVM) decreased in the IGT group with no significant change in the NGT group. Cpt promoted in the IGT group decrease in the area under the curve (AUC) of glucose, and AUC of insulin, with increase of the AUC of the percent of the beta cell function, AUC of HC, and insulin sensitivity index with no significantly change in the NGT group. CONCLUSION: Adults hypertensive obese patients with IGT had decreased significantly in mean fasting level of GH concentrations compared to age, race, and BMI matched hypertensive patients with NGT. Treatment with Cpt induced a significant increased of the GH, with improvement of the metabolism in patients with IGT.
Asunto(s)
Captopril/uso terapéutico , Hipertensión/tratamiento farmacológico , Hipertrofia Ventricular Izquierda/tratamiento farmacológico , Obesidad/complicaciones , Adulto , Anciano , Antihipertensivos/farmacología , Antihipertensivos/uso terapéutico , Glucemia/análisis , Captopril/farmacología , Femenino , Intolerancia a la Glucosa , Prueba de Tolerancia a la Glucosa , Hormona del Crecimiento/sangre , Humanos , Hipertensión/sangre , Hipertensión/etiología , Hipertrofia Ventricular Izquierda/complicaciones , Insulina/sangre , Resistencia a la Insulina , Lípidos/análisis , Masculino , Persona de Mediana Edad , Obesidad/sangre , Factores de TiempoRESUMEN
PURPOSE--To evaluate the effects of captopril (Cpt).on carbohydrate metabolism and growth hormone (GH) in adults hypertensive obese patients with normal (NGT) or impaired (IGT) glucose tolerance and left ventricular hypertrophy. METHODS--Ten patients (53 +/- 8 years), 8 women and 2 men, white, body mass index (BMI) > or = 26kg/m2, left ventricular mass index (LVMI) > 135g/m2 in man and > 110g/m2 in woman, with diastolic blood pressure (DBP) 95-115mmHg after 3 weeks of placebo, were identified by oral glucose tolerance test (OGTT-75g) as either with NGT or IGT, and treated with Cpt 25mg t.i.d. for 8 weeks. At the 8 weeks, dosage was increased to 50mg b.i.d. if DBP > 90mmHg or the decrease of the DBP < 10, during the next 8 weeks. OGTT and clonidine tests (0,04mg/kg) with determinations, every 30 minutes of glucose, insulin, and GH during 2 hours, were performed. RESULTS--Cpt lowered SBP and DBP in the NGT group and IGT group. The LVMI and the left ventricular mass (LVM) decreased in the IGT group with no significant change in the NGT group. Cpt promoted in the IGT group decrease in the area under the curve (AUC) of glucose, and AUC of insulin, with increase of the AUC of the percent of the beta cell function, AUC of HC, and insulin sensitivity index with no significantly change in the NGT group. CONCLUSION--Adults hypertensive obese patients with IGT had decreased significantly in mean fasting level of GH concentrations compared to age, race, and BMI matched hypertensive patients with NGT. Treatment with Cpt induced a significant increased of the GH, with improvement of the metabolism in patients with IGT.
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Captopril , Hipertrofia Ventricular Izquierda , Obesidad , Hipertensión/tratamiento farmacológico , Factores de Tiempo , Glucemia , Hormona del Crecimiento , Captopril , Hipertrofia Ventricular Izquierda , Insulina , Antihipertensivos , Obesidad , Hipertensión/sangre , Hipertensión/etiología , Intolerancia a la Glucosa , Lípidos/análisis , Resistencia a la Insulina , Prueba de Tolerancia a la GlucosaRESUMEN
The objective of the present study was to standardize the analysis of zinc binding on human red blood cell (RBC) membranes in 20 normal adults. The displacement studies revealed that at the maximal stable zinc concentration tested (600 microM), 57% (mean) of the bound 65Zn was displaced and to displace half maximal 65Zn, the stable zinc concentration was 300 microM. Scatchard plots revealed two classes of binding sites for zinc on RBC membranes: one with higher affinity, Kd = 1.20 x 10(-5) M (site I), and the other with lower affinity, Kd = 2.77 x 10(-4) M (site II). Binding sites occupancy was 97% means and 58.5% means for sites I and II, respectively. The displacement was affected by temperature, membrane protein concentration, freezing, thawing, and dialysis. Other metal cations, including Co++, Fe++, and Mn++, had very little effect on 65Zn displacement, in contrast copper displaced 65Zn from its binding sites on RBC membranes. Zinc binding to RBC membranes was rapid and readily reversible in a dynamic equilibrium with its binding sites. It is anticipated that this method will be applicable to studies of a wide variety of diseases specifically related to zinc metabolism in humans as well as in animals.
Asunto(s)
Membrana Eritrocítica/metabolismo , Zinc/sangre , Adulto , Cationes Bivalentes , Cobalto/farmacología , Cobre/farmacología , Femenino , Compuestos Ferrosos/farmacología , Humanos , Cinética , Masculino , Manganeso/farmacología , Proteínas de la Membrana/sangre , Temperatura , Radioisótopos de ZincRESUMEN
A case of a 43-year-old nonobese woman with adiposis dolorosa (Dercum's disease) is reported. Muscle glucose uptake and oxidation before and after ingestion of 75 g of glucose were similar to control group values, although a greater insulin release (16,578 vs 6,242 +/- 1,136 microU/3 h) occurred simultaneously. In vitro studies of abdominal normal and painful subcutaneous adipose tissue of the patient revealed lower responsiveness to norepinephrine and lack of response to the antilipolytic effect of insulin in the painful adipose tissue (0.98 vs 1.43 microM FFA/10(6) cells at 5.0 microM of norepinephrine). The disease was not correlated with the HLA system and there were no alterations in hormonal secretion at the pituitary, adrenal, gonadal, and thyroid levels. These findings indicate the presence of peripheral insulin resistance in this patient with adiposis dolorosa.
Asunto(s)
Adiposis Dolorosa/metabolismo , Hormonas/metabolismo , Tejido Adiposo/metabolismo , Adiposis Dolorosa/genética , Adiposis Dolorosa/inmunología , Adulto , Femenino , Glucosa/metabolismo , Prueba de Tolerancia a la Glucosa , Antígenos HLA/sangre , Humanos , Resistencia a la Insulina , Músculos/metabolismo , Factores de TiempoRESUMEN
A case of a 43-year-old nonobese woman with adiposis dolorosa (Dercum's disease) is reported. Muscle glucose uptake and oxidation before and after ingestion of 75 g of glucose were similar to control group values, although a greater insulin release(16,578 vs 6,242 ñ 1,136 uU/3 h) occurred simultaneously. In vitro studies of abdominal normal and painful subcutaneous adipose tissue of the patient revealed lower responsiveness to norepinephrine and lack of response to the antilipolytic effect of insulin in the painful adipose tissue (0.98 vs 1.43 uM FFA/106 cells at 5.0 uM of norepinephrine). The disease was not correlated with the HLA system and there were no alterations in hormonal secretion at the pituitary, adrenal, gonadal, and thyroid levels. These findings indicate the presence of peripheral insulin resistance in this patient with adiposis dolorosa
Asunto(s)
Tejido Adiposo , Adiposis Dolorosa , Glucosa/metabolismo , Hormonas , Resistencia a la InsulinaRESUMEN
Reports in the literature have shown that acute or chronic zinc administration may cause hyperglycemia, with a fall in serum or insular insulin occurring in experimental animals. On the other hand, under conditions of both acute and chronic hyperglycemia, an increase, a decrease, or a normal level of blood zinc has been observed in studies conducted on humans. Thus, the objective of the investigation described here was to determine the relationship existing among zinc, glucose, and insulin under acute conditions. Thirty-six subjects of both sexes (mean age, 23 yr) were tested at 7:00 A.M. after a 12-h fast. Two antecubital veins of both forearms were punctured and maintained with physiological saline. Three experiments were performed in which zinc was administered orally, and hypertonic glucose and tolbutamid were administered intravenously. Blood samples were then collected over a period ranging from 93 to 240 min after the basal times of -30 and 0 min. Hyperzincemia did not cause changes in plasma glucose or insulin either in the absence of or during perfusion of glucose. Hyperglycemia, hypoglycemia, and hyperinsulinemia did not modify serum zinc levels. These results demonstrate that acute zinc administration did not change carbohydrate metabolism and that sudden variations in glucose and insulin levels did not modify the serum profile of zinc.
Asunto(s)
Glucemia/metabolismo , Tolbutamida/sangre , Zinc/sangre , Administración Oral , Adulto , Femenino , Glucosa/administración & dosificación , Glucosa/farmacología , Humanos , Infusiones Intravenosas , Cinética , Masculino , Valores de Referencia , Factores de Tiempo , Tolbutamida/administración & dosificación , Tolbutamida/farmacología , Zinc/administración & dosificación , Zinc/farmacologíaRESUMEN
Hypo- and hyperzincemia has been reported to cause alterations in the adrenal secretion. To determine the acute effect of zinc on cortisol levels, we studied 27 normal individuals of both sexes aged 20-27 y after a 12-h fast. The tests were initiated at 7:00 AM when an antecubital vein was punctured and a device for infusion was installed and maintained with physiological saline. Zinc was administered orally at 8:00 AM. Subjects were divided into an experimental group of 13 individuals who received doses of 25, 37.5, and 50 mg of zinc and a control group of 14 individual who received 20 mL of physiological saline. Serial blood samples were collected over a period of 240 min after basal samples (-30 and 0 min). We detected an acute inhibitory effect of zinc on cortisol secretion during 240 min of the study period in the experimental group.
Asunto(s)
Corteza Suprarrenal/metabolismo , Hidrocortisona/metabolismo , Zinc/farmacología , Corteza Suprarrenal/efectos de los fármacos , Adulto , Brasil , Humanos , Consentimiento Informado , Periodicidad , Estudiantes de Medicina , Zinc/sangreRESUMEN
Hyperzincemia has been reported to cause alterations in the homeostasis of glycid metabolism. To determine this effect on plasma glucose and insulin levels, we studied 36 normal individuals of both sexes aged 22-26 y after a 12-h fast. The tests were initiated at 7:00 AM when an antecubital vein was punctured and a device for infusion was installed and maintained with physiological saline. Zinc was administered orally at 8:00 AM. Subjects were divided into an experimental group of 22 individuals who received doses of 25, 37.5, and 50 mg of zinc and a control group of 14 individuals. Blood samples were collected over a period of 240 min after the basal samples (-30 and 0 min). We did not detect any change in plasma glucose or insulin levels, a fact that we attribute either to the ineffectiveness of the 50 mg dose of zinc or to the lack of human response to the acute action of this trace element. The individuals who ingested zinc showed a significant fall in plasma cortisol, probably caused by the action of this trace element.
Asunto(s)
Glucemia/metabolismo , Insulina/metabolismo , Zinc/sangre , Adulto , Brasil , Femenino , Humanos , Hidrocortisona/sangre , Masculino , Relación Estructura-Actividad , Estudiantes de MedicinaRESUMEN
The objective of the present study was to report the variations in levels of insulin, free fatty acids and glucose occurring in a group of obese and nonobese women after acute intravenous glucose infusion. The difference between glucose and insulin levels in obese and nonobese women in response to glucose infusion was statistically significant. The mean maximum value for glucose detected in the obese group was 256 mg/dl versus 283 mg/dl in the nonobese group (p < 0.05). Insulin content was 147 muU/ml in the obese group versus 36 muU/ml in the nonobese group (p < 0.05). K (fractional removal rate constant for glucose) values were similar in both groups suggesting that the higher glucose and insulin peaks showed by the obese were due to the higher glucose uptake by the blood rather than its removal impairment.