AJP - Endocrinology and Metabolism, Vol 246, Issue 1 14-E20, Copyright © 1984 by American Physiological Society
Rapid changes in hepatic glucose output after a pulse of growth hormone in dogs
P. Vaitkus, A. Sirek, K. H. Norwich, O. V. Sirek, R. H. Unger and V. Harris
In response to a single intravenous injection of bovine growth hormone (GH,
100 micrograms/kg) the non-steady-state turnover of glucose, as well as
portal levels of insulin (IRI), glucagon (IRG), somatostatin (SRIF), and
glucose were determined in normal conscious dogs. Using the two-compartment
model validated to calculate rapid turnover changes and tracer infusion
methods, the rate of hepatic output of glucose [Ra(t)] was found to be
increased, reaching a maximum of 224 mg/min, 7.4 times the basal rate, 4
min after injection of GH. Ra(t) returned to its basal level 35 min later
in a damped oscillatory manner. Hormone determinations were carried out in
portal venous blood drawn every 2 min for 2 h from an indwelling catheter.
IRG peaked 2 min after GH injection and levels of IRI, SRIF, and glucose
peaked between 4 and 8 min. Hormone concentrations returned to normal,
i.e., were oscillating around base-line levels, about 30 min after GH.
These experiments demonstrate for the first time in vivo that a pulse of GH
causes transient changes of glucose turnover and measurable alterations of
the hormonal homeostasis in the splanchnic area.
