Dose-Dependent Effects of Human Prolactin on the Immature Hypophysectomized

1992 
We have studied dose-dependent effects of highly purified human PRL (39 IU/mg) on the testis of immature (22-day-old) hypophysectomized rats daily supplemented for 7 days with 2, 10, or 30 pg hormone. Dose-dependent stimulation was observed for all parameters: testis weight (1.6- and P-fold above control for 10 and 30 fig PRL), basal and hCG-stimulated testosterone (14- and Pl-fold), intratesticular testosterone (7. and 21-fold) and estradiol (1.2- and I.&fold), LH receptor concentration (1% and 2.5-fold), in vitro pregnenolone production by cholesterol side-chain cleavage enzyme (3-, 5 and 7-fold), and aromatase activity (2.1- and 2.4-fold). The number of Leydig cells exhibiting immunoreactivity toward anti-P450,,,, antiP450,,,,, and anti-3/Y-hydroxysteroid dehydrogenase antibodies also underwent a dose-dependent increase (under conditions revealing many immunopositive cells in hypox control animals). The respective increases were 8- to 14-fold for anti-P450,,, and P450,i,, and 1.5- to 2-fold for anti-3P-hydroxysteroid dehydrogenase. The number of germ cells and the percentage of tubular sections containing late pachytene spermatocytes as most advanced stages of spermatogenesis were subject to similar dosedependent effects. These results suggest that during puberty PRL stimulates testicular function by promoting multiplication and differentiation of Leydig cells (acting at various steps of steroidogenesis and on tissue responsiveness to LH) and germ cells. (Endocrinology
    • Correction
    • Cite
    • Save
    • Machine Reading By IdeaReader
    25
    References
    0
    Citations
    NaN
    KQI
    []