The anti-Müllerian hormone.

Müllerian regression in the male fetus is mediated by a discrete fetal testicular hormone, different from testosterone and synthetized by Sertoli cells. Secretion of AMH begins shortly after testicular differentiation and lasts into the perinatal period; however, the müllerian duct is responsive to AMH only during a short "critical" period at the end of the ambisexual stage. Species-specificity has not been demonstrated in mammals, but avian müllerian ducts do not respond to mammalian AMH, although the mammalian müllerian ducts to respond to avian AMH. Investigations concerning the biochemical nature of AMH have been carried out on incubation media of calf fetal testes. Anti-müllerian activity of the incubation medium is not affected by dialysis, is enhanced by concentration by ultrafiltration and is not correlated with the testosterone content of the medium. Gel filtration of the incubation medium on Sephadex G 200 and Biogel A-5m indicates that the anti-müllerian hormone is a protein of relatively high molecular weight, between 200,000 and 320,000 daltons.