Glucoregulatory function of thyroid hormones: role of pancreatic hormones
Glucose metabolism was investigated in humans before and 14 days after 300 micrograms L-thyroxine (T4)/day using a sequential clamp protocol during short-term somatostatin infusion (500 micrograms/h, 0-6 h) at euglycemia (0-2.5 h), at 165 mg/dl (2.5-6 h), and during insulin infusion (1.0 mU.kg-1.min-1, 4.5-6 h). T4 treatment increased plasma T4 (+96%) and 3,5,3'-triiodothyronine (T3, +50%), energy expenditure (+8%), glucose turnover (+32%), and glucose oxidation (Glucox +87%) but decreased thyroid-stimulating hormone (-96%) and nonoxidative glucose metabolism (Glucnonox, -30%) at unchanged lipid oxidation (Lipox). During somatostatin and euglycemia glucose production (Ra, -67%) and disposal (Rd, -28%) both decreased in euthyroid subjects but remained at -22% and -5%, respectively, after T4 treatment. Glucox (control, -20%; +T4, -25%) fell and Lipox increased (control, +42%; +T4, +45%) in both groups, whereas Glucnonox decreased before (-36%) but increased after T4 (+57%). During somatostatin infusion and hyperglycemia Rd (control, +144%; +T4, +84%) and Glucnonox (control, +326%; +T4, +233%) increased, whereas Glucox and Lipox remained unchanged. Insulin further increased Rd (+76%), Glucox (+155%), and Glucnonox (+50%) but decreased Ra (-43%) and Lipox (-43%). All these effects were enhanced by T4 (Rd, +38%; Glucox, +45%; Glucnonox, +35%; Ra, +40%; Lipox, +11%). Our data provide evidence that, in humans, T3 stimulates Ra and Rd, which is in part independent of pancreatic hormones.
- Research Organization:
- Univ. of Hannover (Germany, F.R.)
- OSTI ID:
- 6407141
- Journal Information:
- Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 256; ISSN AJPHA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
AMINO ACIDS
ANIMALS
BIOLOGICAL FUNCTIONS
CARBOHYDRATES
CARBOXYLIC ACIDS
FUNCTIONS
GLUCOSE
GLYCOLYSIS
HEXOSES
HOMEOSTASIS
HORMONES
INSULIN
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPIDS
MAMMALS
MAN
METABOLISM
MONOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
PEPTIDE HORMONES
PITUITARY HORMONES
PRIMATES
SACCHARIDES
SOMATOSTATIN
THYROID HORMONES
THYROXINE
TRACER TECHNIQUES
TRIIODOTHYRONINE
TRITIUM COMPOUNDS
TSH
VERTEBRATES