The effects of prolactin on rat testicular steroidogenic enzyme activities

A. K. Munabi, V. Mericq, M. C. Gelato, M. C. Koppelman, B. D. Albertson, D. L. Loriaux, F. Cassorla

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


To investigate whether hyperprolactinemia directly affects rat testicular steroidogenesis, we examined the effects of prolactin (PRL) on microsomal 3β-hydroxysteroid dehydrogenase (3β-HSD), 17-hydroxylase (17-OH), 17,20-desmolase (17,20-D), 17-ketosteroid reductase (17-KSR) and aromatase enzyme activities. Adult hypophysectomized, gonadotropin-treated Fisher rats were rendered hyperprolactinemic by isografting pituitaries under the kidney capsule. The controls received skeletal muscle. All rats were sacrificed 7 days later and serum PRL was measured in each animal. PRL levels were 198 ± 14 ng/ml in the hyperprolactinemic rats and 4.3 ± 0.6 ng/ml in the controls (P<0.001). The testes were resected, pooled according to PRL levels, and microsomes were prepared from each pool. The activities of the 3β-HSD, 17-OH, 17,20-D, 17-KSR and aromatase were measured using as substrates 14C dehydroepiandrosterone, progesterone, 17-hydroxyprogesterone, androstenedione and testosterone, respectively. Hyperprolactinemia was associated with significant decreases in 3β-HSD, 17-OH, 17,20-D, 17-KSR and aromatase activities when compared to controls (P<0.005). We conclude that prolactin may have a direct effect on rat testicular steroidogenesis which appears to be independent of changes in gonadotropin secretion.

Original languageEnglish (US)
Pages (from-to)47-48
Number of pages2
JournalHormone and Metabolic Research
Issue number1
StatePublished - 1985
Externally publishedYes

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical


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