RESUMEN
We evaluated whether melatonin administration to pregnant rats during the final week of pregnancy affects prepubertal secretion of luteinizing hormone (LH), follicle stimulating hormone (FSH), and prolactin in offspring. Melatonin was administered in the drinking water from day 14 to delivery. LH, FSH and prolactin concentrations were determined in plasma sampled from offspring between 5 and 30 days in the dark portion of the diurnal cycle. Administration of 2 or 20 microg/ml melatonin did not affect LH or FSH in male or female offspring. The 20-microg/ml dose caused a significant increase in prolactin in males and females at day 15. In contrast, melatonin, 2 or 20 microg/ml, decreased prolactin at days 25 and 30 in females and day 25 in males. Thus, prenatal melatonin exposure alters prolactin secretion, but not that of LH and FSH in infantile and prepubertal male and female rats.
Asunto(s)
Depuradores de Radicales Libres/administración & dosificación , Gonadotropinas/sangre , Melatonina/administración & dosificación , Efectos Tardíos de la Exposición Prenatal , Prolactina/efectos de los fármacos , Animales , Animales Recién Nacidos , Femenino , Hormona Folículo Estimulante/sangre , Hormona Luteinizante/sangre , Hormona Luteinizante/efectos de los fármacos , Masculino , Embarazo , Prolactina/sangre , Ratas , Factores Sexuales , Factores de TiempoRESUMEN
This study examined the effect of suckling on nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d, a histochemical marker for nitric oxide synthase, NOS) reactivity and neuronal NOS mRNA expression in the paraventricular (PVN) and supraoptic (SON) nuclei of lactating rats. Freely nursing (non-separated) dams and those separated from pups for 12 h and then reunited for 0, 15, 30, 60, 90, 120 and 180 min were used for the study. Dams separated from pups and sacrificed at time zero (without reunion) showed a significant decrease in NADPH-d staining and NADPH-d positive cells as well as in the NOS mRNA expression in the PVN and SON compared to that observed in non-separated dams. Reunion with pups and restoration of suckling significantly increased NADPH-d reactivity after 15, 30, 60 min, but not after 90, 120 and 180 min compared to non-reunited pups-deprived dams. A pattern of NADPH-d reactivity and neuronal NOS mRNA expression indistinguishable from that observed during free lactation was reinstated shortly (15 min) after the restoration of suckling stimulus, suggesting that the NADPH-d reactivity in lactation depends on the presence of the suckling stimulus. These results show that suckling stimulus may play a modulatory role in the regulation of NOS reactivity in the magnocellular neurones of the hypothalamic PVN and SON during lactation.
Asunto(s)
Expresión Génica/fisiología , Lactancia/fisiología , NADPH Deshidrogenasa/metabolismo , Óxido Nítrico Sintasa/genética , Núcleo Hipotalámico Paraventricular/fisiología , Núcleo Supraóptico/fisiología , Animales , Animales Recién Nacidos/anatomía & histología , Femenino , Histocitoquímica/métodos , Área Hipotalámica Lateral/enzimología , Hibridación in Situ , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Coloración y Etiquetado , Aumento de PesoRESUMEN
Phenotype and gene frequencies of ABO and RH (D) systems were studied in 37,846 random blood donors in five zone of Nigeria (South West) (Yoruba)--Zone A, North West (Hausa-Fulani)--Zone B, Plateau (Birom)--Zone C, South East (Igbo)--Zone D and North East (Kanuri)--Zone E). We assessed the micro differences of genetic markers of ABO and RH blood groups between the ethnic groups in the ABO and RH blood group systems. Gene frequencies were ABO *O = 0.7068, ABO *A = 0.1490, ABO *B = 0.1443, RH *D = 0.8150 and results are similar to those earlier reported. Phenotype frequencies of the blood groups were in agreement with Hardy-Weinberg equilibrium expectations, except in two zones B and C where deviation was thought to be due to a high frequency of blood group AB.
Asunto(s)
Sistema del Grupo Sanguíneo ABO/genética , Población Negra/genética , Etnicidad/genética , Frecuencia de los Genes/genética , Sistema del Grupo Sanguíneo Rh-Hr/genética , Adulto , Donantes de Sangre/estadística & datos numéricos , Transfusión Sanguínea , Femenino , Genética de Población , Humanos , Masculino , Evaluación de Necesidades , Nigeria , Fenotipo , Vigilancia de la Población , Características de la Residencia/estadística & datos numéricosRESUMEN
The exact role of leptin in fasting has not been completely elucidated. To determine whether leptin can act in fasting to influence plasma estrogen levels and nitric oxide synthase reactivity in food regulating centers of the brain, we fasted female rats for 4 days and treated them i.p. with vehicle or 100 microg of recombinant mouse leptin as 1 ml on the 3rd and 4th day twice daily (10.00 and 17.00 h). Proestrus blood was collected at 10.00, 14.00, 18.00 and at 22.00 h, plasma obtained and assayed for estrogen (E2) and leptin levels. Verification of ovulation occurrence was by examining the oviduct for extruded ovum. The rat brains were removed and processed for nitric oxide synthase reactivity in the ventromedial hypothalamus (VMH) and arcuate nucleus (ARC) using NADPH-diaphorase histochemistry, a marker for neurons expressing NOS enzyme. Leptin effect on dependable variables such as food intake, water intake and body weight gain was also investigated. Four days fasting significantly decreased body weight, estrogen and postfast leptin levels, nitric oxide reactivity in the VMH and ARC nucleus and stopped ovulation in many (4 out of 5) rats fasted and given vehicle. Leptin treatment significantly increased plasma estrogen and postfast leptin levels, restored ovulation in many (4 out of 5) rats and increased nitric oxide reactivity in the VMH and ARC. Leptin significantly inhibited food intake, water intake and gain in body weight during recommenced feeding. These observations suggest that leptin could act in the pituitary-ovarian axis during fasting to improve reproductive function by partly stimulating estrogen secretion.
Asunto(s)
Núcleo Arqueado del Hipotálamo/metabolismo , Estrógenos/sangre , Privación de Alimentos/fisiología , Leptina/sangre , Óxido Nítrico Sintasa/metabolismo , Núcleo Hipotalámico Ventromedial/metabolismo , Animales , Núcleo Arqueado del Hipotálamo/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Peso Corporal/fisiología , Ingestión de Líquidos/efectos de los fármacos , Ingestión de Líquidos/fisiología , Ingestión de Alimentos/efectos de los fármacos , Ingestión de Alimentos/fisiología , Femenino , Leptina/farmacología , Ratones , NADPH Deshidrogenasa/metabolismo , Óxido Nítrico Sintasa/efectos de los fármacos , Proestro/metabolismo , Ratas , Ratas Wistar , Núcleo Hipotalámico Ventromedial/efectos de los fármacosRESUMEN
Treadmill exercise was performed and electrolyte loss estimated in apparently healthy young adult males. Subjects walked at four mph for 20 minutes at 28.9 +/- 0.2 degrees C (SEM) ambient temperature and 75.3 pc relative humidity. Gradient was incrementally increased from 0 degrees to 4 degrees (0 pc-7 pc) during the 20 minutes. Mean concentrations of sodium, potassium, and chloride in the sweat were 67 +/- 0.1 meg/litre (SEM), 4.3 +/- 0.1 meg/litre (SEM) and 55 +/- 0.9 meg/litre (SEM) respectively. The electrolyte concentration was significantly related to work load and body surface area (p < 0.001). The results indicate that the quantity of electrolytes lost in the sweat of Nigerian males during exercise is close to those of Caucasians under similar conditions.