Waning of Anti-Müllerian Activity: An Early Sign of Sertoli Cell Maturation in the Developing Pig

Testicular anti-Mullerian activity was evaluated in pigs from birth to 180 days. Anti-Mullerian activity was low during the first 3 postnatal days, and rose to reach its highest level between 10 and 19 days. Thereafter, anti-MUllerian capacity steadily declined, and fell abruptly after 60 days, at a time when pubertal changes are not yet detectableby histologicalexamination and the blood-testis barrier has not yet formed. The ultrastructuralappearance of Sertolicellsfrom birth to 80 days suggestsactiveglycoprotein biosynthesis,but no correlationcould be establishedbetween the fine structure of Sertolicellsand the degree of anti-Mullerian activity. We conclude that decreased biosynthesis of anti-Mullerian hormone is an early sign of testicular maturation in the postnatal pig.