Autoregulation of testicular luteinizing hormone receptors in hypogonadal (hpg/hpg) mice |
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Authors: | Amador A. Parkening T. Beamer W. Bartke A. Collins T. J. |
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Affiliation: | (1) Department of Obstetrics and Gynecology, The University of Texas Health Science Center at San Antonio, 78284 San Antonio, Texas;(2) Department of Anatomy, The University of Texas Medical Branch, 77550 Galveston, Texas;(3) The Jackson Laboratory, 04609 Bar Harbor, Maine |
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Abstract: | 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.These studies were supported by NIH Grants HD 12642 and HD 12671 (AB) and Grant CA-24145 (WGB). |
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Keywords: | luteinizing hormone (LH) receptors hypogonadal mice testes testosterone |
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