Glucagon stimulates insulin-like growth factor binding protein-1 secretion in healthy subjects, patients with pituitary insufficiency, and patients with insulin-dependent diabetes mellitus.
Glucagon (1-1.5 mg) was administrated iv as a bolus dose to healthy individuals (n = 7), patients with GH deficiency (n = 14), and patients with insulin-dependent diabetes mellitus (IDDM; n = 6). Thereafter, blood samples for determination of serum glucose, insulin, insulin-like growth factor-binding protein-1 (IGFBP-1), GH, and insulin-like growth factor-I (IGF-I) concentrations were collected for 180 min. IGFBP-1 concentrations increased significantly in response to glucagon, with maximal values observed at 90 min [in healthy subjects from 36 +/- 6 to 58 +/- 10 micrograms/L (P < 0.05), in GH-deficient patients from 36 +/- 4 to 54 +/- 6 micrograms/L (P < 0.001), and in IDDM patients from 115 +/- 18 to 167 +/- 27 micrograms/L (P < 0.05)]. The IGFBP-1 elevation was delayed in relation to the glucagon-induced increase in glucose and insulin concentrations. When the groups were combined, the individual IGFBP-1 peak value observed at 90 min was inversely correlated to the individual peak value of insulin observed at 15-30 min (r = -0.743; P < 0.001). In GH-deficient patients, serum GH concentrations remained undetectable (< 0.2 micrograms/L), and IGF-I concentrations were unchanged after the glucagon injection. In healthy subjects and IDDM patients, mean GH levels did not change significantly, whereas mean IGF-I concentrations decreased slightly at 30 min. In conclusion, glucagon increased serum IGFBP-1 concentrations in spite of increases in glucose and insulin. These results suggest that glucagon is a stimulator of IGFBP-1.
Hilding
A
A
Department of Endocrinology, Karolinska Institute, Stockholm, Sweden.
Brismar
K
K
Thorén
M
M
Hall
K
K
D000328:Adult; D002352:Carrier Proteins / Q000097:blood / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D005260:Female; D005934:Glucagon / Q000494:pharmacology*; D013006:Growth Hormone / Q000097:blood / Q000172:deficiency*; D006801:Humans; D006943:Hyperglycemia / Q000097:blood; D007328:Insulin / Q000097:blood; D018970:Insulin-Like Growth Factor Binding Protein 1; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013002:Somatomedins / Q000378:metabolism
D002352:Carrier Proteins; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D013002:Somatomedins; D013006:Growth Hormone; D005934:Glucagon