Urinary concentrations of conjugated oestrone and pregnanediol-3-glucuronide were measured during and after spontaneous and induced oestrus and during pregnancy. Behavioural oestrus was preceded by a rise in oestrone values from less than 10 ng/mg creatinine (Cr) to peaks of 45 ng/mg Cr. Maximal lordotic response and mating activity coincided with the decline in oestrone levels. After presumed ovulation, urinary pregnanediol glucuronide concentrations increased from less than 5 to 15-30 ng/mg Cr. Further increases in this steroid (to 60-80 ng/mg Cr) occurred 114 days after mating, presumably coincident with implantation. These high levels of pregnanediol glucuronide were maintained for 3 weeks, began to decline 1 week before parturition and fell to a nadir (less than 5 ng/mg Cr) immediately after delivery. When FSH was administered i.m. for 5 days, urinary oestrone values rose markedly and were maximal (580 ng/mg Cr) on Day 7. Mating first occurred on Day 20 and 500 i.u. hCG were given i.m. Urinary pregnanediol glucuronide levels during the next 5 months were similar to those in the previous year during pregnancy with values rising 105-108 days after mating. However, no birth occurred. These results support the suggestion that pandas exhibit delayed implantation and demonstrate that the panda is responsive to exogenous gonadotrophins.
Concentrations of immunoreactive estrone conjugates, pregnanediol-3-glucuronide, and luteinizing hormone were measured and indexed to creatinine in daily urine samples from three female black mangabeys (Cercocebus arerrirnus), Daily observations of menstruation and perineal tumescence were recorded. The mean t_ SEM lengths of the menstrual cycle [apparent cycle length of 26.0 k 0.8 days determined by observation of intermenstrual intervals (n = 26); physiologic cycle length of 3 1.3 2 5 days determined by urinary endocrine analysis (n = 4)], follicular phase 116.5 I 4 days (n=4)], and luteal phase L14.8 C 1 day (n = 4)] were determined. The apparent cycle length is probably more accurate.Perineal tumescence began during or shortly after menstruation, increased concomitantly with increasing follicular phase conjugated estrone values, and reached maximal size in the periovulatory period. Ovulation was closely followed by a drop in conjugated estrone levels, an increase in urinary pregnanediol-3-glucuronide, and perineal detumescence. Peak concentrations of conjugated estrone and luteinizing hormone values were coincident. Pregnanediol-3-glucuronide accurately reflected luteal function in the black mangabey.Knowledge of the menstrual cycle parameters and their correlation to perineal tumescence was used to time artificial inseminations. Semen was obtained by rectal electroejaculation. Coagulum and extended semen, or trypsin-digested coagulum, were used for insemination. One insemination of trypsin-digested coagulum at the external os of the cervix resulted in a probable conception, followed by apparent abortion after 3 weeks.
The purpose of this study was to investigate a possible contribution by somatostatin to the impairment in glucose-stimulated secretion of insulin during aging. Pancreatic islets of Langerhans were isolated from male Sprague-Dawley rats aged 2- to 24-months and challenged in vitro with effectors of insulin secretion. Concentrations of insulin, glucagon, and somatostatin were determined by radioimmunoassay. The impairment of glucose-stimulated secretion of insulin which characterizes islets isolated from aged rats may be overcome by treatment of islets with antibodies to somatostatin. Enhanced availability and/or effectiveness of endogenous pancreatic somatostatin during aging may be responsible for the modified pattern of glucose-stimulated secretion of insulin.
Summary. In both species of zebra, breeding males had higher urinary androgen concentrations (ng androgens/mg Cr) than did non-breeding bachelor males (30\m=.\0\ m=+-\ 5\ m=. \ 0 (N = 9) versus 11\m=.\4 \ m=+-\2\m=.\8,(N = 7) in the plains zebra; 19\m=.\0 \ m=+-\ 2\m=.\2 (N = 17) versus 10\m=.\7 \ m=+-\ 1\m=.\2 (N = 14) in the Grevy's zebra). In the more stable family structure of the plains zebra (single male non-territorial groups) variations in androgen concentrations could not be ascribed to any measured variable. In the Grevy's zebra, androgen values were significantly lower in samples taken from territorial (breeding) males which had temporarily abandoned their territories (N = 4) and the urinary androgen concentration for a male on his territory was negatively correlated with the time since females last visited the territory.
The purpose of this study was to investigate the sensitivity of insulin secretion to glucose and its possible relationship to changes in islet glucose utilization during aging. Pancreatic islets of Langerhans were isolated from male Sprague-Dawley rats aged 2- to 24-months and perifused in vitro with glucose. Insulin concentration was determined by radioimmunoassay. Glucose utilization was assessed by measuring the rate of conversion of 3H-5-D-glucose to 3H-H20. The sensitivity of isolated, perifused islets to glucose was reduced during aging. Less glucose metabolism, however, may be required to elicit comparable release of insulin by islets from old than from young rats.
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