Effects of an LHRH agonist and gonadotropins on testicular prolactin receptors
| Autor: | A. Arimura, C.M. Turkelson, J.B. Fishback |
|---|---|
| Rok vydání: | 1982 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Every other day Hypophysectomy endocrine system diseases Gonadotropins Equine Receptors Prolactin Physiology medicine.drug_class medicine.medical_treatment Population Receptors Cell Surface Binding Competitive Biochemistry Gonadotropin-Releasing Hormone Cellular and Molecular Neuroscience Endocrinology Internal medicine Testis medicine Animals Receptor education Saline education.field_of_study LHRH Agonist Chemistry Prolactin Rats Kinetics Gonadotropin hormones hormone substitutes and hormone antagonists |
| Zdroj: | Peptides. 3:845-850 |
| ISSN: | 0196-9781 |
| DOI: | 10.1016/0196-9781(82)90026-2 |
| Popis: | Effects of administration of the LHRH agonist D-Leu 6 -LHRH ethylamide (LHRH-A), gonadotropin (PMS), and their interaction on testicular prolactin (PRL) receptor levels were investigated in rats. LHRH-A (2 μg/100 g body wt.) or saline was injected SC daily, and PMS (5 IU) injected every other day. In intact rats, the testicular PRL receptor levels were about 400 fmoles/testis after either 1 or 7 daily injections of saline. Administration of LHRH-A decreased PRL receptors to 12% of that of saline-injected control rats at day 1, and to 20% at day 2, and PRL receptor levels were partially restored to 55% at day 7. In hypophysectomized rats given daily injections of saline for 7 days PRL receptor levels were only 20% of those in saline-injected intact rats. Injections of LHRH-A in hypophysectomized animals did not further decrease PRL receptor numbers at this time. Administration of PMS to hypophysectomized rats for 7 days partially reversed the reduction of PRL receptors that occurred after hypophysectomy, to 46% of those in intact controls. Injections of LHRH-A into hypophysectomized, PMS-treated animals did not significantly alter PRL receptors on day 1 (117% of that of saline-injected, hypophysectomized, PMS-treated rats at day 1) or day 2 (96% of same-day controls), but decreased PRL receptors on day 7 to 102 fmoles/testis (55% of same-day controls). This latter concentration is nearly the same as that in saline-injected, 7-day hypophysectomized rats not treated with PMS. These findings suggest that: (1) the effects of LHRH-A on testicular PRL receptors differ depending on the presence or absence of gonadotropin, (2) gonadotropin, primarily FSH, maintains some population of testicular PRL receptors, and these gonadotropin-dependent PRL receptors are suppressed by direct action of LHRH-A upon the testes, and (3) there is a population of PRL receptors which is not affected by LHRH-A or gonadotropin. |
| Databáze: | OpenAIRE |
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