EFFECT OF THYROID STATUS ON THE OXIDATIVE CAPACITY OF SERTOLI CELLS ISOLATED FROM IMMATURE RAT TESTIS

Our previous studies indicate the Sertoli cell as a target for thyroid hormone action at testis level. In the present study we evaluated the effect of thyroid hormone on Sertoli cell oxidative capacity measured by specific cytochrome oxidase (COX) activity and intracellular adeno sine triphosphate (ATP) content. Sertoli cells were isolated from 21-d ay-old rats. Hypothyroidism, induced from the day of birth by administ ration of 0.025% methimazole, was characterized by a severe delay of b ody and testis growth and resulted in a lower COX activity (-40%, p le ss than or equal to 0.01) and a lower ATP content (-35%, p less than o r equal to 0.01) by isolated Sertoli cells. Administration of triiodot hyronine (10 mu g/100 g body wt on alternate days) to hypothryoid rats improved body and testis growth and restored both COX activity and AT P content. The presence of high-affinity, low-capacity binding sites f or triiodothyronine in Sertoli cell mitochondria also was demonstrated . This study, unlike that carried out on the whole testis from adult r ats, demonstrates that thyroid hormone affects the energy metabolism o f Sertoli cells from midpubertal rat testes.