AJP - Endocrinology and Metabolism, Vol 238, Issue 4 358-E363, Copyright © 1980 by American Physiological Society
Food and protein intake, glucagon, and distribution of alpha-aminoisobutyrate in the rat
J. K. Tews and A. E. Harper
Distribution of alpha-aminoisobutyric acid (AIB) in the rat was modified by
food, dietary protein, and glucagon. In rats last fed 24 h before AIB
injection, AIB clearance from plasma and uptake into liver were greater in
rats fed a high-protein diet (60% casein) than in rats fed the control diet
(18% casein); AIB clearance from plasma and uptake into muscle were lowered
by a low-protein diet (6% casein). Feeding rats lowered clearance of AIB
from plasma in low- and high-protein groups. Distribution ratios (AIB
concentration in tissue water/AIB in plasma) were low in all tissues but
liver during the first 7 h after feeding high protein when compared to the
control values; ratios were low in muscle, heart, and kidney after feeding
low protein. Maximum ratios occurred at different times for different
tissues; the time was delayed by the high-protein diet in all tissues but
liver. Glucagon increased all ratios in rats fed the control or low-protein
diets, with the smallest changes occurring in liver and muscle from
low-protein rats.
