Effect of glucagon on zinc excretion in anesthetized dogs.
Victery-W; Levenson-R; Vander-AJ
Am J Physiol Renal Physiol 1981 Apr; 240(4):F299-F305
Glucagon induced renal vasodilation changes in zinc (7440666) excretion were compared to acetylcholine (51843) induced alterations in dogs. Male dogs, anesthetized with 30 milligrams/kilogram (mg/kg) pentobarbital, were infused with 5 or 50 nanograms (ng)/kg/minute glucagon in saline, or saline alone. Sequential 15 minute urine collections were made and arterial blood samples were taken. Effects of 25 micrograms/minute acetylcholine infused into the renal artery on zinc excretion and renal function were compared. In three other dogs, ultrafilterable plasma zinc concentrations were evaluated using zinc-65, intravenously infused 2 hours before infusion of 50ng/kg/minute glucagon. Radioactivity in samples of blood, plasma, filtrate, and urine was counted. Zinc excretion in control animals was relatively constant. The lower dose of glucagon increased zinc excretion slightly in all four animals, with a return to control concentrations during the recovery hour in 75 percent. However, 50ng/kg/minute glucagon increased zinc excretion as much as 50 percent, with a return to control concentrations within 1 hour in all but one animal. Plasma zinc tended to decrease in the control and both treatment groups, possibly in relation to surgical trauma. Low dose glucagon tended not to increase urine flow and sodium excretion significantly; however, 50ng/kg/minute glucagon increased mean urine flow 0.15 milliliter (ml)/minute and sodium excretion 35 microequivalents/minute at peak values, while significantly increasing both glomerular filtration rate and effective renal plasma flow. Acetylcholine did not significantly alter zinc excretion despite large increases in urinary sodium excretion and urine flow. In dogs receiving zinc-65, ultrafilterability did not alter throughout the experiments. Glucagon increased zinc-65 clearance by 37 to 75 percent, with clearance of ultrafilterable zinc from 3.8 to 1.3ml/minute. The authors conclude that plasma glucagon, elevated over its physiological range, acutely increases urinary zinc excretion. Altered zinc excretion is probably related to changes in the glomerular filtration rate.
NIOSH-Publication; NIOSH-Grant; Metabolites; Chemical-indicators; Analytical-models; Exposure-limits; Histology; Chemical-analysis; Toxic-materials; Tissue-distribution; Metabolic-study; Body-distribution
Physiology University of Michigan 6811 Medical Science II Ann Arbor, Mich
Other Occupational Concerns; Grants-other
American Journal of Physiology: Renal Physiology
University of Michigan at Ann Arbor, Ann Arbor, Michigan