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

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Abstract

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
Volume17
Issue number1
DOIs
StatePublished - Jan 1 1985

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ASJC Scopus subject areas

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

Cite this

Munabi, A. K., Mericq, V., Gelato, M. C., Koppelman, M. C., Albertson, B. D., Loriaux, D. L., & Cassorla, F. (1985). The effects of prolactin on rat testicular steroidogenic enzyme activities. Hormone and Metabolic Research, 17(1), 47-48. https://doi.org/10.1055/s-2007-1013448