The fatty acid pool in adipose tissue.

Adipose tissue, stimulated by epinephrine (1, 2) or other hormones (3-6), discharges fatty acids into an incubation medium. It also can take up acids and esterify them (7). The possibility thus arises that the opposing effects, uptake and lipolysis, might be the forward and reverse aspects of a single process (8, 9). I f this is the case, the quantity of fatty acids taken up and the quantity released should tend to vary inversely in response to various stimuli, and the fluxes should involve a common intracellular fatty acid pool. The present study was undertaken to define the chemical nature of the heptane-soluble organic acids in adipose tissue and the functional relation of this pool to uptake and lipolysis. The results suggest that it is composed mainly of long chain fatty acids produced by lipolysis of cellular fat. Uptake appears to be an independent process, distinct from the re-esterification of acids in the lipolytic pool.