Human pancreatic tumor growth hormone-releasing factor: dose-response relationships in normal man

• Published in: The journal of clinical endocrinology and metabolism Vol. 58; no. 5; p. 838
• Main Authors: Vance, M L, Borges, J L, Kaiser, D L, Evans, W S, Furlanetto, R, Thominet, J L, Frohman, L A, Rogol, A D, MacLeod, R M, Bloom, S
• Format: Journal Article
• Language: English
• Published: United States 01.05.1984
• Subjects: Adult; Blood Glucose - metabolism; Dose-Response Relationship, Drug; Gastrointestinal Hormones - blood; Growth Hormone - blood; Growth Hormone-Releasing Hormone - pharmacology; Humans; Hydrocortisone - blood; Insulin - pharmacology; Luteinizing Hormone - blood; Male; Pancreatic Hormones - blood; Prolactin - blood; Thyrotropin - blood
• ISSN: 0021-972X
• DOI: 10.1210/jcem-58-5-838

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.