RESUMEN
GnRH sterilization vaccines have been developed for various practical and clinical reasons. However, conjugation of GnRH peptide to carrier protein has many drawbacks, hampering the further commercialization of GnRH vaccines. In this study, a new nonconjugated GnRH vaccine, D-Lys6-GnRH-tandem-dimer peptide (TDK), emulsified in Specol adjuvant was investigated for its immunocastration efficacy in young male rats. Prepubertal male rats were randomly allocated into three groups (n = 12): control (no treatment), surgically castrated or immunized against 100 µg TDK in Specol adjuvant at 6 weeks of age (with a booster 8 weeks later). Blood samples (for antibody titers and hormone concentrations) were collected at 2-week intervals until rats were killed (18 weeks of age). Compared to intact controls, active immunization against TDK reduced (P < 0.05) serum concentrations of testosterone, inhibin B, LH and FSH, prevented the onset of spermatogenesis at puberty. Furthermore, mRNA expressions of GnRH receptor, LH-ß and FSH-ß in the pituitary, LH receptor, FSH receptor, inhibin α, ßA and ßB subunit in the testes were decreased in immunocastrated rats compared to intact controls (P < 0.05). These results demonstrate for the first time that GnRH-tandem-dimer peptide emulsified in Specol is a promising veterinary sterilization medicine.
Asunto(s)
Hormona Liberadora de Gonadotropina/inmunología , ARN Mensajero/efectos de los fármacos , Maduración Sexual/efectos de los fármacos , Espermatogénesis/efectos de los fármacos , Testículo/efectos de los fármacos , Vacunas Conjugadas/farmacología , Animales , Hormona Folículo Estimulante/metabolismo , Hormona Folículo Estimulante de Subunidad beta/efectos de los fármacos , Hormona Folículo Estimulante de Subunidad beta/genética , Subunidades beta de Inhibinas/efectos de los fármacos , Subunidades beta de Inhibinas/genética , Inhibinas/efectos de los fármacos , Inhibinas/genética , Inhibinas/metabolismo , Hormona Luteinizante/efectos de los fármacos , Hormona Luteinizante/metabolismo , Hormona Luteinizante de Subunidad beta/efectos de los fármacos , Hormona Luteinizante de Subunidad beta/genética , Masculino , Péptidos , Hipófisis/efectos de los fármacos , Hipófisis/metabolismo , ARN Mensajero/metabolismo , Distribución Aleatoria , Ratas , Receptores de HFE/efectos de los fármacos , Receptores de HFE/genética , Receptores de HL/efectos de los fármacos , Receptores de HL/genética , Receptores LHRH/efectos de los fármacos , Receptores LHRH/genética , Testículo/crecimiento & desarrollo , Testículo/metabolismo , Testosterona/metabolismo , VacunaciónRESUMEN
AIMS: Activin E is a newly identified member of the transforming growth factor-beta superfamily. To assess the role of activin E in glucose/energy metabolism, we investigated the transcriptional regulation of activin E in the liver. MAIN METHODS: Northern blotting, Western blotting, quantitative real-time polymerase chain reaction (PCR), reporter assays and chromatin immunoprecipitation assays were used in this study. KEY FINDINGS: Insulin up-regulated activin E expression at the mRNA and protein level in HepG2 cells. Reporter assays revealed that the putative, functional, promoter sequence of human activin E gene was responsible for the effect of insulin. Mutational analysis of the promoter revealed that CCAAT/enhancer-binding proteins (C/EBPs) play a key role in regulating activin E expression and in the stimulatory effect of insulin on activin E transcription. Chromatin immunoprecipitation assays revealed that the C/EBPs can bind to the activin E promoter in HepG2 cells. The expression of activin E mRNA was up-regulated in the liver of diet-induced obese mice. SIGNIFICANCE: These observations suggest that activin E plays a pathophysiological role in glucose metabolism.
Asunto(s)
Activinas/metabolismo , Metabolismo de los Hidratos de Carbono/genética , Regulación de la Expresión Génica , Glucosa/metabolismo , Subunidades beta de Inhibinas/efectos de los fármacos , Hígado/metabolismo , Activinas/genética , Animales , Northern Blotting , Western Blotting , Línea Celular Tumoral , Hepatocitos/efectos de los fármacos , Humanos , Hipoglucemiantes/farmacología , Subunidades beta de Inhibinas/genética , Subunidades beta de Inhibinas/metabolismo , Insulina/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Regiones Promotoras Genéticas , ARN Mensajero/biosíntesis , ARN Mensajero/efectos de los fármacosRESUMEN
BACKGROUND/AIMS: Activin A is an autocrine inhibitor of cell growth in the liver. The biological activity of activin A is mediated by a heteromeric receptor complex. Follistatin (FS) binds to activin and inhibits its biological effects, and acts as a negative regulator of muscle cells. The role of activin receptors during liver regeneration following a hepatectomy has not been fully assessed. This study investigates the mechanism underlying how activin receptors regulate hepatocyte growth, and the effects of intravenous administration of FS during liver regeneration. METHODOLOGY: The expression of both activins and activin receptors in the liver after a 70% partial hepatectomy (HT) was assessed by RT-PCR and immunohistochemistry. FS 315 or 288 was infused for different periods of time based on changes in hepatocyte activin receptor expression after HT. RESULTS: Activin receptor expression peaked between 48 and 72 hours after HT. 72 hours after HT, an injection of FS 315 resulted in a more potent stimulation of DNA synthesis and produced a greater increase in body weight compared with the control rats. CONCLUSIONS: The expression of activin receptors after peak DNA synthesis might be a key component in the downregulation of DNA synthesis. Intravenous administration of FS 315 might promote liver regeneration and have anabolic actions.
Asunto(s)
Receptores de Activinas Tipo II/metabolismo , Folistatina/metabolismo , Subunidades beta de Inhibinas/metabolismo , Regeneración Hepática/fisiología , Proteínas/metabolismo , Receptores de Activinas Tipo II/efectos de los fármacos , Animales , Folistatina/administración & dosificación , Folistatina/farmacología , Hepatectomía , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Subunidades beta de Inhibinas/efectos de los fármacos , Inyecciones Intravenosas , Regeneración Hepática/efectos de los fármacos , Masculino , Proteínas/efectos de los fármacos , RatasRESUMEN
BACKGROUND: Inhibin-B decreases and activin increases FSH secretion in adults. We investigated whether an FSH-inhibin/activin feedback loop exists before or during puberty. METHODS: FSH secretion was stimulated with 10 microg/kg leuprolide acetate (GnRH agonist) in 18 girls, ages 1.0-13.2 years, and 11 boys, ages 8.9-15.2 years, with variations in pubertal development, and in five normal 9- to 10-year-old girls. Blood, obtained at 0, 0.5, 1, 2, 4, 8, 12, 16, 20 and 24 h after GnRH agonist, was analysed for LH, FSH, activin-A, inhibin-A, inhibin-B, follistatin 288 and estradiol/testosterone. RESULTS: FSH increased within 30 min of GnRH agonist administration with a peak greater in girls than boys (P=0.0006). Baseline inhibin-B was greater in boys than girls (P=0.01), while baseline activin-A concentrations were greater in girls. GnRH agonist-stimulated FSH increased inhibin-B in girls by 8 h and in boys by 20 h (P<0.05), but did not affect activin-A. Inhibin-B increases were seen only in girls older than 5 years. CONCLUSIONS: An inhibin-B-FSH feedback loop exists prior to the onset of puberty in girls older than 5 years. Sex differences in activin-A and inhibin-B concentrations may be responsible for sex differences in serum FSH concentrations.
Asunto(s)
Activinas/sangre , Hormona Liberadora de Gonadotropina/agonistas , Gónadas/efectos de los fármacos , Subunidades beta de Inhibinas/sangre , Inhibinas/sangre , Leuprolida/farmacología , Hipófisis/efectos de los fármacos , Activinas/efectos de los fármacos , Adolescente , Factores de Edad , Desarrollo Óseo/fisiología , Niño , Femenino , Hormona Folículo Estimulante/sangre , Gónadas/fisiología , Trastornos del Crecimiento/sangre , Trastornos del Crecimiento/tratamiento farmacológico , Humanos , Subunidades beta de Inhibinas/efectos de los fármacos , Inhibinas/efectos de los fármacos , Masculino , Hipófisis/fisiología , Pubertad , Pubertad Precoz/sangre , Pubertad Precoz/tratamiento farmacológico , Valores de Referencia , Caracteres SexualesRESUMEN
This study investigated the role of the secretory granule proteins, secretogranin II (SgII) and chromogranin A (CgA), in the differential secretion of FSH and LH from LbetaT2 mouse gonadotroph cells. Exogenous activin, which synergises with GnRH, is essential for the release of FSH from these cells, but also has stimulatory effects on LH and enhances GnRH-induced LH secretion. Two experiments are reported. In experiment 1, cultures were supplemented with activin (0-50 ng/ml), with and without a daily 1 h treatment of 10 nM GnRH, for 3 days. Protein secretion and mRNA levels were measured. In experiment 2, cells were treated with activin (50 ng/ml) alone, a daily 1 h treatment of 10 nM GnRH, or a combination of both for 6 days. In addition, cells exposed to activin+GnRH for 3 days were subsequently left untreated or given activin or GnRH alone for a further 3 days for comparison with cells maintained in activin+GnRH for 6 days. Protein secretion, intracellular protein and mRNA levels were measured. FSH secretion was stimulated, dose dependently, by activin and this effect increased synergistically in the presence of GnRH. The close correlation between secreted and intracellular FSH and FSHbeta mRNA levels was maintained in cells that had undergone treatment withdrawal after previous exposure to activin+GnRH, but there was no correlation between FSH and the granins. These results are consistent with the view that FSH released in response to activin/GnRH is constitutively secreted via a granin-independent pathway. SgII secretion mirrored the GnRH-induced secretion of LH, but was unaffected by activin, which stimulated LH secretion and had a detrimental effect on CgA mRNA transcription. This confirms previous observations that the LH released in response to GnRH is co-released with SgII via a regulated, granin-dependent pathway, and, in addition, suggests that activin may stimulate LH secretion through a constitutive, granin-independent pathway.
Asunto(s)
Cromograninas/fisiología , Hormona Folículo Estimulante/metabolismo , Hormona Luteinizante/metabolismo , Hipófisis/metabolismo , Proteínas/fisiología , Receptores de Activinas/efectos de los fármacos , Receptores de Activinas/genética , Activinas/farmacología , Animales , Línea Celular , Cromogranina A , Cromograninas/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Regulación de la Expresión Génica/efectos de los fármacos , Hormona Liberadora de Gonadotropina/farmacología , Subunidades beta de Inhibinas/efectos de los fármacos , Subunidades beta de Inhibinas/genética , Subunidades beta de Inhibinas/farmacología , Ratones , Hipófisis/citología , Hipófisis/efectos de los fármacos , Proteínas/efectos de los fármacos , Receptores LHRH/efectos de los fármacos , Receptores LHRH/genética , Factores de TiempoRESUMEN
The findings that bone marrow fibroblastoid stromal cells are important for activin A production prompted our investigation of activin A expression in fibroblast-like synoviocytes in joint capsule in this and previous studies. In the proliferative reactive synovial membrane obtained from rheumatoid arthritis patients, activin A is detected prominently in the fibroblastoid synovial cells, as well as in the smooth muscle and the endothelial layer of the arteries in these vascularized proliferative tissues. The concentration of activin A in the rheumatoid arthritis synovial fluid was 33.6+/-5.0 ng/ml, much higher than the activin A content of osteoarthritis fluid (10.0+/-1.1 ng/ml). Furthermore, our previous studies also showed that inflammatory cytokines, such as interleukin (IL)-1, transforming growth factor (TGF)-beta, interferon (IFN)-gamma, IL-8, and IL-10 markedly enhance the expression of activin A mRNA in synoviocytes. These findings are consistent with our studies in regard to the regulatory control of activin A production in bone marrow stroma and monocytes. In addition, the relationship of activin A to IL-6-induced biological activities in various cell types was also investigated. Although activin A has not been directly associated with inflammatory processes, future studies are needed to investigate its production in response to the accumulated levels of inflammatory cytokines in the synovium of the patients, as well as the quantitative differences in activin A concentrations in many patients with other inflammatory diseases.