Effects of GH on urea, glucose and lipid metabolism, and insulin sensitivity during fasting in GH-deficient patients.
Fasting-related states of distress pose major health problems, and growth hormone (GH) plays a key role in this context. The present study was designed to assess the effects of GH on substrate metabolism and insulin sensitivity during short-term fasting. Six GH-deficient adults underwent 42.5 h of fasting on two occasions, with and without concomitant GH replacement. Palmitate and urea fluxes were measured with the steady-state isotope dilution technique after infusion of [9,10-3H]palmitate and [13C]urea. During fasting with GH replacement, palmitate concentrations and fluxes increased by 50% [palmitate: 378 +/- 42 (GH) vs. 244 +/- 12 micromol/l, P < 0.05; palmitate: 412 +/- 58 (GH) vs. 276 +/- 42 microM, P = 0.05], and urea turnover and excretion decreased by 30-35% [urea rate of appearance: 336 +/- 22 (GH) vs. 439 +/- 43 micromol. kg-1. h-1, P < 0.01; urea excretion: 445 +/- 43 (GH) vs. 602 +/- 74 mmol/24 h, P < 0.05]. Insulin sensitivity (determined by a euglycemic hyperinsulinemic clamp) was significantly decreased [M value: 1.26 +/- 0.06 (GH) vs. 2.07 +/- 0.22 mg. kg-1. min-1, P < 0.01] during fasting with GH replacement. In conclusion, continued GH replacement during fasting in GH-deficient adults decreases insulin sensitivity, increases lipid utilization, and conserves protein.
Nørrelund
Helene
H
Medical Dept. M (Endocrinology and Diabetes), Arhus Kommunehospital, DK-8000 Aarhus C, Denmark. helenenorrelund@dadlnet.dk
Djurhuus
Christian
C
Jørgensen
Jens Otto Lunde
JO
Nielsen
Søren
S
Nair
K Sreekumaran
KS
Schmitz
Ole
O
Christiansen
Jens Sandahl
JS
Møller
Niels
N
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D004393:Dwarfism, Pituitary / Q000188:drug therapy* / Q000378:metabolism*; D005215:Fasting / Q000097:blood / Q000378:metabolism*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D013006:Growth Hormone / Q000008:administration & dosage* / Q000097:blood; D020249:Hormone Replacement Therapy / Q000379:methods; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000494:pharmacology; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood; D008297:Male; D014508:Urea / Q000097:blood / Q000378:metabolism*
D001786:Blood Glucose; D007328:Insulin; D008055:Lipids; D014508:Urea; D013006:Growth Hormone; D005947:Glucose