Follow-up study on the effects of thyroid hormone administration on androgen metabolism of peripubertal rat Sertoli cells

Abstract

Panno ML, Salerno M, Lanzino M, De Luca G, Maggiolini M, Straface SV, Prati M, Palmero S, Bolla E, Fugassa E, Andò S. Follow-up study on the effects of thyroid hormone administration on androgen metabolism of peripubertal rat sertoli cells. Eur J Endocrinol 1995;132:236–41. ISSN 0804–4643 The inhibitory effect of triiodothyronine (T3) given in early postnatal life on Sertoli cell proliferative activity, leading to their precocious terminal differentiation, has been demonstrated previously. However, data concerning the role of thyroid hormone on androgen metabolism of Sertoli cells during the same period are still lacking. In this study we performed a time-course investigation on the effects of T3 treatment on testosterone metabolism in Sertoli cells isolated from 2-, 3- and 4-weeks-old euthyroid rats. Triiodothyronine (3 μg/100 g body wt) was given ip., during the last week prior to sacrifice. Sertoli cells from all animal groups initially were cultured under basal conditions during the first 24 h and subsequently in the presence of testosterone (0.5 μmol/l) with or without T3 (1 nmol/l) for an additional 24 h. This treatment given to 2-week-old animals resulted in reduced testicular growth. As far as androgen metabolism is concerned, T3 in vivo and in vitro treatment in 2- and 3-week-old animals induced a lowering of dihydrotestosterone ± 3α-diol with an enhancement of the two other 5α-reduced androgens. The effect was much less pronounced in the oldest group. In both 2-and 3-week-old treated rats a marked reduction of oestradiol was observed, which indicates an inhibition of aromatase activity, mainly in younger animals. This enzyme has been reported to be extremely active in Sertoli cells of rats (of the same strain) between the age of 5 and 20 days, but it decreases rapidly thereafter. The results suggest that T3 given in early postnatal life could modify directly the androgen metabolism in Sertoli cells. Sebastiano Andò, Cattedra di Fisiopatologia Endocrina, Dipartimento di Biologia Cellulare, Università della Calabria, 87030 Arcavacata di Rende, Cosenza, Italy