Reduction in prostatic concentration of endogenous dihydrotestosterone in rats by hyperprolactinemia

Chung Lee*, David Hopkins, James M. Holland

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Persistently high levels of circulating prolactin can be achieved in male rats when pituitaries from female donors are grafted under the renal capsule. Enhanced growth of the lateral prostate can be accomplished by an apparent synergistic effect of excess prolactin with subphysiologic doses of testosterone. To define this effect we measured the endogenous dihydrotestosterone (DHT) concentrations in rat prostate lobes. Twenty Sprague‐Dawley male rats (250 g) were castrated and given subcutaneous implants of silastic tubing filled with 1 cm of crystalline testosterone. Ten of these rats simultaneously received two pituitary grafts under the renal capsule. The remaining ten rats received intrarenal skeletal muscle grafts as controls. Four weeks later, the weight (mg ± SE) of the ventral and dorsal lobes were not significantly different between the two groups, while the lateral lobe was significantly (P < 0.01) heavier in rats with pituitary grafts (121.4 ± 7.5) than in controls (81.7 ± 10.4). Endogenous DHT in the tissue extracts was determined by radioimmunoassay following KMnO4 treatment to eliminate testosterone. The concentration of DHT (ng/g tissue ± SE) was significantly (P < 0.01) lower in the lateral prostate of graft‐bearing animals (4.40 ± 0.29) than in the controls (5.98 ± 0.34). These results indicate that, in the rat, hyperprolactinemia induced by pituitary grafts is associated with a heavier lateral prostate and a lower concentration of endogenous DHT in that tissue. These results also suggest that the action of prolactin in the rat prostate is not mediated through the action of androgen.

Original languageEnglish (US)
Pages (from-to)361-367
Number of pages7
JournalThe Prostate
Volume6
Issue number4
DOIs
StatePublished - 1985

Keywords

  • endogenous dihydrotestosterone
  • hyperprolactinemia
  • pituitary graft

ASJC Scopus subject areas

  • Oncology
  • Urology

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