Estrogen promotes germ cell and seminiferous tubule development in the baboon fetal testis.

The foundation for development of the male reproduction system occurs in utero, but relatively little is known about the regulation of primate fetal testis maturation. Our laboratories have shown that estrogen regulates key aspects of the physiology of pregnancy and fetal development. Therefore, in the present study, we characterized and quantified germ cells and Sertoli cells in the fetal baboon testis in late normal gestation (i.

Age-related changes in diurnal rhythms and levels of gonadotropins, testosterone, and inhibin B in male rhesus monkeys (Macaca mulatta).

Testosterone shows circadian rhythms in monkeys with low serum levels in the morning hours. The decline relies on a diminished frequency of LH pulses. Inhibin B shows no diurnal patterns.

Effect of continuous intravenous administration of human metastin 45-54 on the neuroendocrine activity of the hypothalamic-pituitary-testicular axis in the adult male rhesus monkey (Macaca mulatta).

In agonadal juvenile male monkeys, continuous administration of human metastin 45-54 (hu metastin 45-54) leads to desensitization of its receptor, G protein-coupled receptor 54 (GPR54), and decreased LH. The present study extended this observation to the adult male monkey, a more preclinically relevant model in which robust activity in the hypothalamic-pituitary-testicular axis is present. Continuous iv infusion of hu metastin 45-54 at either 200 or 400 microg/h elicited a marked rise in circulating LH that peaked 2-3 h after initiation of treatment.

Inhibitory and stimulatory regulation of testicular inhibin B secretion by luteinizing hormone and follicle-stimulating hormone, respectively, in the rhesus monkey (Macaca mulatta).

This study examined the relative role of FSH and LH in governing testicular inhibin B secretion in the rhesus monkey. Adult male monkeys, rendered hypogonadotropic and hypogonadal by administration of a GnRH receptor antagonist (acyline), were implanted with testosterone (T)-filled or empty capsules. Following T-induced restoration of spermatogenesis, both groups received recombinant human FSH and vehicle for 12 d.