Effects of gonadectomy and testosterone replacement on growth hormone response to alpha 2 adrenergic stimulation in the male rat.
The growth hormone (GH) response to clonidine in reserpine-pretreated rats is a putative in vivo model to reflect activation of central postsynaptic alpha 2 receptors. In the present study the influence of testosterone on the responsiveness of central alpha 2 receptors was investigated using this method. One week after operation the GH response to clonidine was drastically reduced in gonadectomized adult male rats compared to sham-operated controls. Testosterone replacement completely antagonized the effect. The results suggest an influence of testosterone on central postsynaptic alpha 2 receptors or on structures connected to these receptors.
D000818:Animals; D002369:Castration; D003000:Clonidine / Q000494:pharmacology; D013006:Growth Hormone / Q000097:blood*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000187:drug effects*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D012110:Reserpine / Q000494:pharmacology; D013739:Testosterone / Q000494:pharmacology*
D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D013739:Testosterone; D012110:Reserpine; D013006:Growth Hormone; D003000:Clonidine