Testosterone decreases β-adrenoceptor sites in rat pineal gland and brain
Testosterone administration to orchidectomized rats brought about a significant, 55% decrease of β-adrenoceptor sites in the pineal gland, assessed from the specific binding of radioactive dihydroalprenolol (DHA). The changes in density of binding sites were not accompanied by significant modificati...
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| Autores principales: | , , |
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| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_03009564_v53_n1_p49_Vacas |
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| Sumario: | Testosterone administration to orchidectomized rats brought about a significant, 55% decrease of β-adrenoceptor sites in the pineal gland, assessed from the specific binding of radioactive dihydroalprenolol (DHA). The changes in density of binding sites were not accompanied by significant modifications of the Kd. FSH or LH treatment of acutely castrated animals did not affect pineal β-adrenoceptor binding. The depressive effects of testosterone in β-adrenergic receptors were also observed in crude membrane fractions of medial basal hypothalamus and cerebral cortex. Sympathetic denervation of the pineal gland by superior cervical ganglionectomy did not abolish the changes in pineal β-adrenoceptor density caused by testosterone. Hormone effects did not depend on a direct effect of the hormone on β-adrenoceptor sites because testosterone did not compete with [3H]-DHA for the binding sites, in vitro. These results suggest that testosterone depresses pineal β-adrenergic sites by acting mainly on post-synaptic sites. © 1982 Springer-Verlag. |
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