Plasma GH responses to GHRH and insulin-induced hypoglycemia in man.
Changes in plasma GH levels in response to an intravenous bolus injection of 200 micrograms GHRH-44 or 0.1 U/kg body weight regular insulin were examined in normal men who were pre-treated with 200 micrograms GHRH-44 or 0.1 U/kg body weight regular insulin 120 min in advance. The prior bolus injection of GHRH-44 inhibited the plasma GH response to the subsequent administration of GHRH-44 whereas the plasma GH response to the subsequent injection of insulin was not influenced by the prior administration of GHRH-44. The prior administration of insulin attenuated the plasma GH response to the subsequently given GHRH-44. These results suggest that desensitization of GHRH receptors in somatotrophs and/or somatostatin hypersecretion induced by increase in plasma GH levels following the prior GHRH-44 administration may be involved in the mechanism by which the prior GHRH-44 administration or insulin-induced hypoglycemia suppressed plasma GH responses to the following GHRH-44 administration. Sudden suppression of somatostatin secretion, which causes rebound of GH secretion, may occur in insulin-induced hypoglycemia.
D000328:Adult; D055598:Chemical Phenomena; D002621:Chemistry; D004305:Dose-Response Relationship, Drug; D013006:Growth Hormone / Q000097:blood*; D013007:Growth Hormone-Releasing Hormone / Q000008:administration & dosage*; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000139:chemically induced*; D007328:Insulin / Q000494:pharmacology*; D008297:Male
D007328:Insulin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone