Autoregulation of testicular luteinizing hormone receptors in hypogonadal (hpg/hpg) mice.
The autoregulation of testicular luteinizing hormone (LH) receptors was studied in hypogonadal (hpg/hpg) and normal mice. The basal concentration of LH receptors was more than three-fold higher in hpg/hpg than in normal mice. After injection of hCG, hpg/hpg mice showed a decrease in LH receptor levels which was not observed in normal mice. Plasma testosterone was undetectable in hpg/hpg mice, even after treatment with a single dose of hCG. Plasma prolactin levels were higher in hpg/hpg than in normal mice. The increase in basal LH receptor levels is thought to be due to a compensatory mechanism in which elevated prolactin could play a role. The differences between hpg/hpg and normal mice in the autoregulation of LH receptors observed could be due to the "hypersensitivity" of the physiologically immature testis in hpg/hpg mice to the action of hCG, to gonadotropin deficiency, particularly during the earlier stages of development, or to a direct effect of the hpg locus on the metabolism of LH receptors.
D000818:Animals; D006063:Chorionic Gonadotropin / Q000378:metabolism; D007006:Hypogonadism / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains / Q000378:metabolism*; D011388:Prolactin / Q000097:blood; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011974:Receptors, LH; D013737:Testis / Q000378:metabolism*; D013739:Testosterone / Q000097:blood
D006063:Chorionic Gonadotropin; D011956:Receptors, Cell Surface; D011974:Receptors, LH; D013739:Testosterone; D011388:Prolactin