The steroidogenic capacity of the aging rat testis.
Factors bearing on the steroidogenic capacity of the aging testis have been examined in Sprague-Dawley rats between 3 and 24 months of age. Neither the number nor the binding affinity of testicular receptors for 125I-hCG changed with age. The ability of the aging testis to synthesize cholesterol from octanoate was similarly undiminished. Testicular conversion of cholesterol to pregnenolone, the gonadotropin-responsive, rate-limiting portion of the androgenic pathway, remained near young adult levels with advancing age. The rate at which the testis converted pregnenolone to testosterone actually increased by almost 25% in the oldest rats. Hence, the steroidogenic capacity of the Sprague-Dawley rat testis does not decline with advancing age.
D000375:Aging; D000818:Animals; D002784:Cholesterol / Q000096:biosynthesis; D008297:Male; D011284:Pregnenolone / Q000096:biosynthesis*; D051381:Rats; D013739:Testosterone / Q000096:biosynthesis*
D013739:Testosterone; D011284:Pregnenolone; D002784:Cholesterol