Flutamide has been given to late pregnant
sows and early postnatal boars but for a much shorter interval,
and Sertoli cell numbers were not evaluated. However, Sertoli
cell numbers were increased in young ram lambs following
prenatal exposure to testosterone . While this might
seem to contrast with the results obtained here, administration
of exogenous testosterone increases negative hypothalamic
feedback and may well reduce testicular testosterone concentrations
and hence reduce testosterone signaling within the
testis . The observed increases in circulating LH and
FSH associated with flutamide treatment observed in the
current experiments are consistent with reduced negative
feedback at the hypothalamus with concomitant increased
trophic drive to the anterior pituitary. These data and the
changes in testicular expression of HSPA5, a known androgen
receptor-responsive gene, argue strongly that androgen receptor
antagonism was effective both systemically and locally
within the gonad.