Testosterone投与後の "はねかえり現象" に関する実験的研究:睾丸内ステロイド生合成における酵素活性の変化
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概要
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To examine the endocrinological and enzymatic aspects of the rebound phenomenon induced after cessation of testosterone (T) administration, adult male Wistar rats were treated with 03 mg of testosterone propionate daily for 39 days.<BR>Serum LH and T levels were both at the control level when the rebound phenomenon was recognized. Testicular T concentration, however, remained at a higher level.<BR>At the same time, the changes in 3β-hydroxysteroid dehydrogenase (3β-HSD), 17α-hydroxylase, C<SUB>17</SUB>- C<SUB>20</SUB> lyase and 17β-hydroxysteroid dehydrogenase (17β-HSD) activities were investigated using the whole homogenate of rat testis. 3β-HSD, 17α-hydroxylase and C<SUB>17</SUB>-C<SUB>20</SUB> lyase activities began to elevate at the time when serum LH began to elevate. 3β-HSD and C<SUB>17</SUB>-C<SUB>20</SUB> lyase activities returned to the control level after about 30 and 50 days of cessation of T administration, respectively. 17α-hydroxylase activity and testicular T level continued higher although serum LH concentration was at the control level. 17β-HSD activity was strongly suppressed and returned to the control level after about 30 days of cessation of T administration.<BR>It was assumed that the rebound phenomenon was induced by the higher level of testicular T which was produced by the elevated enzyme activity of 17α-hydroxylase under the characteristic conditions in rat testis, perhaps where the sensitivity of 17α-hydroxylase for LH was increased following cessation of T administration.
- 一般社団法人 日本内分泌学会の論文