Abstract
Summary
Skeletal muscle FFA contents are increased during starvation in the rat. An attempt has been made to determine the source of these FFA by incubating the intact rat diaphragm preparations of fed and 72-hour starved animals in palmitate-albumin solutions containing palmitate-1-14C and by assaying the composition of the plasma and tissue FFA and tissue TGFA of fed and starved animals. The 1-min uptake of label was minimally influenced by starvation and not at all by incubation in ouabain, Amytal or 100% nitrogen. Steady-state levels of label were minimally increased by starvation but the increases were insufficient to account for the enhanced tissue FFA levels. Tissue FFA composition differed from both plasma FFA and tissue TGFA. Starvation from 0 to 96 hours did not affect tissue FFA composition. These results are compatible with the following conclusions: The initial association between the albumin-FFA complex and the diaphragm is not affected by metabolic inhibitors; intracellular FFA do not approach the composition of either the plasma or muscle TGFA during progressive starvation suggesting selectivity in uptake or utilization or both, the selectivity of the processes responsible for tissue FFA size and composition is unaltered by starvation, and tissue FFA are increased during starvation primarily from intracellular sources.
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