Prolactin, growth hormone, and luteinizing hormone in the maintenance of testicular luteinizing hormone receptors.

To elucidate further pituitary influence on testicular function, we studied the effect of PRL, GH, and LH alone or in various combinations on the maintenance of testicular LH receptor concentration and testosterone synthesis in response to LH (testicular responsiveness) in hypophysectomized adult rats. Hypophysectomy reduced LH receptor concentration by 80% and testicular responsiveness to LH by 70% 7 days after surgery. Treatment with PRL (75 or 150 μg/day) or with GH (75 or 150 μg/day) initiated within 6 h after surgery and continued twice daily for 6 days partially prevented the loss of LH receptors. The effect of PRL (150 μg/day) plus GH (150 μg/day) on LH receptor concentration was additive. The combination of LH (5 μg/day), PRL, and GH prevented any loss of LH receptors after hypophysectomy. A positive effect of LH on its receptor occurred in the presence of PRL. Treatment of hypophysectomized rats with 5 /μg LH plus 150 /μg PRL enhanced the effect observed with PRL alone (1.31 pmol/testis vs. 1.68 ...

[1]  R. Swerdloff,et al.  Etiologies of sexual maturation: a model system based on the sexually maturing rat. , 1976, Recent progress in hormone research.

[2]  R. Sharpe.  hCG-induced decrease in availability of rat testis receptors , 1976, Nature.

[3]  H. Bohnet,et al.  Localization of prolactin binding in prostate and testis: The role of serum prolactin concentration on the testicular LH receptor. , 1977, Acta endocrinologica.

[4]  R. Hauger,et al.  Testicular receptors for luteinizing hormone after immunoneutralization of gonadotrophin releasing hormone in the male rat. , 1977, The Journal of endocrinology.

[5]  H. Bohnet,et al.  Effect of prolactin and growth hormone on prolactin and LH receptors in the dwarf mouse. , 1976, Journal of reproduction and fertility.

[6]  A. Jones,et al.  The effects of interstitial cell-stimulating hormone, prolactin, and bovine growth hormone on the transplantable Leydig cell tumor in the mouse. , 1974, Cancer research.

[7]  Y. D. Chen,et al.  Regulation of testicular LH receptors by homologous hormone: in vitro studies on receptor occupancy and receptor loss. , 1977, Biochemical and biophysical research communications.

[8]  K. Catt,et al.  Gonadotropin-induced regulation of luteinizing hormone receptors and desensitization of testicular 3':5'-cyclic AMP and testosterone responses. , 1977, Proceedings of the National Academy of Sciences of the United States of America.

[9]  G. Niswender,et al.  Radioimmunoassay of steroids. , 1970, Acta endocrinologica. Supplementum.

[10]  K. Catt,et al.  Regulation of luteinizing hormone receptors in testicular interstitial cells by gonadotropin. , 1976, Biochemical and biophysical research communications.

[11]  R. Hauger,et al.  Pituitary regulation of Leydig cell function in the adult male rat. , 1977, The Journal of endocrinology.

[12]  H. Bern,et al.  Synergistic Role of Prolactin in Response of Male Rat Sex Accessories to Androgen.∗ , 1957, Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine.