Changes in plasma concentrations of inhibin A and inhibin B throughout sexual maturation in the male chimpanzee

Profiles of circulating plasma inhibin A and inhibin B during sexual matura tion in male chimpanzees were investigated by using two-site enzyme-linked immunoassay (ELISA). Plasma concentrations of testosterone and pituitary go nadotropins were also measured. Concentrations of inhibin B, testosterone, luteinizing hormone (LH) and prolactin increased with age throughout prepub erty to adulthood, whereas inhibin A level was low and there were no age-re lated changes in concentrations of either inhibin A and follicle-stimulatin g hormone (FSH). Inhibin B showed an inverse correlation with FSH in adult (7 years or order) but not in immature (6 years or younger) male chimpanzee s. There was no correlation between plasma levels of FSH and testosterone t hroughout the period of sexual maturation. However, testosterone levels wer e positively correlated with inhibin B levels. These results suggest that c irculating inhibin B is involved in the regulation of FSH secretion after p uberty in adult male chimpanzees, and also that circulating inhibin B is an important form of inhibin as a marker of Sertoli cell function in adult ma le chimpanzees.