Human pancreatic tumor growth hormone-releasing factor: dose-response relationships in normal man.
Human pancreatic GRF (hpGRF-40; 1 microgram/kg, iv) selectively stimulates GH release in normal men (9). We now report the effects of graded doses of hpGRF-40 on GH release in 12 normal men. Mean peak increments in serum GH after vehicle and the various doses of hpGRF-40 were 1.13, 11.40, 14.60, 17.01, 14.45, and 15.60 ng/ml after vehicle and 0.1, 0.33, 1.0, 3.3, and 10 micrograms/kg hpGRF-40 (iv bolus), respectively. Peak values were observed 30-60 min after hpGRF-40 treatment. There was considerable variability of responsiveness among individual subjects, and no dose-response relationship between the doses and maximal GH values was found. However, the higher doses of 3.3 and 10.0 micrograms/kg resulted in a more prolonged and biphasic pattern of GH release. A side effect of facial flushing of less than 5-min duration occurred in 4 or 6 subjects who received 3.3 micrograms/kg and in all 5 who received 10 micrograms/kg of hpGRF-40. No changes in serum glucose, LH, TSH, PRL, plasma cortisol, or 8 enteropancreatic hormones occurred after hpGRF-40 treatment. There were small increases in serum somatomedin C levels 24 h after the administration of various doses of hpGRF-40 in 11 of 13 studies. Plasma immunoreactive GRF levels measured 5 min after injection were 0.09, 2.0, 4.9, 23.9, and 66.6 ng/ml after 0.1, 0.33, 1.0, 3.3, and 10 micrograms/kg hpGRF-40, respectively. Serum GH responses after insulin-induced hypoglycemia were compared to GH responses after hpGRF-40. Comparable peak GH stimulation occurred with both provocative tests. Mean +/- SEM peak GH was 20.2 +/- 1.0 ng/ml after insulin and 20.9 +/- 3.2 after hpGRF-40 treatment. hpGRF-40 selectively stimulates GH release in normal men over a dose range of 0.1-10 micrograms/kg and is an effective probe to investigate the dynamics of GH release.
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005768:Gastrointestinal Hormones / Q000097:blood; D013006:Growth Hormone / Q000097:blood; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D010187:Pancreatic Hormones / Q000097:blood; D011388:Prolactin / Q000097:blood; D013972:Thyrotropin / Q000097:blood
D001786:Blood Glucose; D005768:Gastrointestinal Hormones; D007328:Insulin; D010187:Pancreatic Hormones; D011388:Prolactin; D007986:Luteinizing Hormone; D013972:Thyrotropin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D006854:Hydrocortisone