Modulation of the onset of postnatal development of H+-ATPase-rich cells by steroid hormones in rat epididymis

Abstract

Vacuolar type H+-ATPase is involved in lumenal acidification of the epididymis. This protein is highly expressed in narrow and clear cells where it is located in the apical pole, and it contributes to proton secretion into the lumen. We have previously shown that in rats, epididymal cells rich in H+ATPase appear during postnatal development and reach maximal numbers at 3-4 wk of age. The factors that regulate the appearance of these cells have not been investigated, but androgens, estrogens, or both may be involved. This study examined whether neonatal administration of estrogens (diethylstilbestrol [DES] or ethinyl estradiol) or an antiandrogen (flutamide), or the suppression of androgen production via administration of a GnRH antagonist (GnRHa), was able to alter the appearance of cells rich in H+-ATPase in the rat epididymis when assessed at age 25 days. Surprisingly, all of these treatments were able to significantly reduce the number of H+-ATPase positive cells; this was determined by immunofluorescence and confirmed by Western blotting. In contrast, neonatal coadministration of DES and testosterone maintained the expression of H+-ATPase in the epididymis at Day 25 despite the high level of concomitant estrogen exposure. These findings indicate that androgens, acting via the androgen receptor, are essential for the normal development of epididymal cells rich in H+-ATPase, and that treatments that interfere directly or indirectly with androgen production (GnRHa, DES) or action (flutamide, DES) will result in reduced expression of H+-ATPase. Our findings do not exclude the possibility that estrogens can directly suppress the postnatal development of cells in the epididymis that are rich in H+-ATPase, but if this is the case, this suppression can be prevented by testosterone administration.