Elevated plasma glucagon from a protein-rich meal or infusion does not elicit significant changes in renal hemodynamics, indicating it cannot account for postprandial increases in RBF and GFR.
Does glucagon mediate protein-induced increases in renal blood flow and glomerular filtration rate during the postprandial state in dogs?
Elevated plasma levels of glucagon do not account for protein-mediated increases in renal blood flow and glomerular filtration rate during the postprandial state.
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.
Premen et al. (1985) studied this question. High protein meat meal and glucagon infusion vs. Normal protein control meal was evaluated on Renal blood flow (RBF) and glomerular filtration rate (GFR). Elevated plasma glucagon from a protein-rich meal or infusion does not elicit significant changes in renal hemodynamics, indicating it cannot account for postprandial increases in RBF and GFR.