AJP - Renal Physiology, Vol 248, Issue 5 656-F662, Copyright © 1985 by American Physiological Society
Postprandial regulation of renal hemodynamics: role of pancreatic glucagon
A. J. Premen, J. E. Hall and M. J. Smith Jr
The aim of this study was to ascertain the quantitative importance of
glucagon in mediating protein-induced increases in renal blood flow (RBF)
and glomerular filtration rate (GFR) during the postprandial state. Six
chronically instrumented conscious dogs were each subjected to four
protocols: normal protein control meal (C); high protein meat meal (M);
somatostatin infusion and meat (S + M); and glucagon infusion. C produced
small increases in RBF (12 +/- 2%) and GFR (14 +/- 2%) without changing
arterial plasma glucagon. M produced marked increases in RBF (38 +/- 4%),
GFR (41 +/- 5%), and glucagon (from 23.3 +/- 3.6 to 73.3 +/- 7.1 pg/ml)
over a 3-h period. During S + M, RBF and GFR failed to increase while
glucagon was suppressed by 36 +/- 8% over a 2-h period. When S was stopped,
glucagon rose to 100 +/- 13.9 pg/ml over the next hour, yet RBF and GFR
increased by only 14 +/- 4 and 10 +/- 3%, respectively. Glucagon infusion
(3 ng X kg-1 X min-1, i.v.) markedly elevated plasma glucagon to 131.6 +/-
27.3 pg/ml, yet neither RBF nor GFR significantly changed. These data
indicate that while a protein-rich meat meal does elevate arterial plasma
glucagon, the rise is not great enough to elicit significant changes in
renal hemodynamics. Thus, elevated plasma levels of glucagon cannot account
for protein-mediated increases in RBF and GFR during the postprandial
state.
