18 NEITHER TESTOSTERONE NOR FSH ARE RESPONSIBLE FOR DECREASED PRODUCTION OP AMH BY BOVINE SERTOLI CELLS IN PRIMARY CULTURE

Abstract

Production of anti-Müllerian hormone (AMH) by Sertoli cells is maximal during the fetal and neonatal period, and tapers off in the course of postnatal development. To determine the factors responsible for the repression of AMH secretion after birth, Sertoli cells, isolated from immature calves, were plated in an hormonally defined medium and cultured in the presence of 0.1 mM MIX. AMH was assayed in the culture medium using a competition-type RIA capable of detecting 1.5 ng. The proportion of neosynthesized AMH was calculated by determining the amount of immunoreactive AMH unaffected by cycloheximide treatment in conditions where 92 % of protein neosynthesis is inhibited. AMH production by Sertoli cells, expressed per 24 hrs and per 106 cells, fell from 90 ng on the day following plating to 1.5 at day 7. The proportion of AMH synthesized after day 1 was 35 % on day 2 and 88 % on day 3. FSH, 2.5 μg/ml, and testosterone, 2 μM, were added to the culture medium on days 2 and 3, immunoreactive AMH was measured in the culture medium at day 3. Mean daily production of AMH by 106 Sertoli cells was 28.6±2.6 ng in control cultures, 24.6±2.8 in FSH-treated ones and 26.6±3.4 after testosterone treatment. Differences were not significant by analysis of variance. In the same conditions, FSH increased cyclic AMP production approximately tenfold. Further studies are in progress to determine which factors are essential to the continued production of AMH by Sertoli cells in vitro.