Influence of growth hormone on glucose-induced glucose uptake in normal men as assessed by the hyperglycemic clamp technique.
To determine whether physiological increments in circulating GH concentrations influence glucose-induced glucose uptake (GIGU), two-step sequential hyperglycemic clamp (plasma glucose, 6 and 14 mmol/L) studies were performed in six normal subjects with and without GH infusion (40 ng/kg.min). The latter resulted in serum GH levels of 15 +/- 1 (+/- SE) microgram/L. Infusion of somatostatin (250 micrograms/h during step 1 and 750 micrograms/h during step 2) together with a replacement dose of insulin (1.1 pmol/kg.min) resulted in serum insulin levels comparable to basal levels in both studies. The GIGU ([3-3H]glucose), assessed as the difference between steps 2 and 1 glucose utilization during the final 60 min of each step (150 min) was markedly impaired during GH infusion (with GH, 1.1 +/- 0.2 mg/kg.min; without GH, 3.1 +/- 0.3 mg/kg.min; P less than 0.001). Moreover, the percent increase in glucose uptake was considerably reduced during hypersomatotropinemia (with GH, 44 +/- 9%; without GH, 97 +/- 11%; P less than 0.01). In the GH infusion as well as control studies, endogenous glucose production (EGP) was similar at the two levels of glycemia, whereas GH infusion approximately doubled EGP [2.3 +/- 0.2 vs. 1.1 +/- 0.3 mg/kg.min and 2.0 +/- 0.4 vs. 1.1 +/- 0.4 mg/kg.min (step 1 and 2, respectively)]. We conclude that moderate hypersomatotropinemia for several hours is characterized by impaired GIGU as well as augmented EGP.
Orskov
L
L
First University Clinic of Internal Medicine, Kommunehospitalet, Aarhus, Denmark.
Schmitz
O
O
Jørgensen
J O
JO
Arnfred
J
J
Abildgaard
N
N
Christiansen
J S
JS
Alberti
K G
KG
Orskov
H
H
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D002096:C-Peptide / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005934:Glucagon / Q000097:blood; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D013006:Growth Hormone / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000097:blood; D007332:Insulin Infusion Systems; D008297:Male; D013004:Somatostatin / Q000494:pharmacology
D001786:Blood Glucose; D002096:C-Peptide; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D013004:Somatostatin; D013006:Growth Hormone; D005934:Glucagon; D005947:Glucose