Metabolism of isolated fat cells from various tissue sites in the rat: influence of hemorrhagic hypotension.

The in vitro lipolytic response to norepinephrine by rat adipocytes from epididymal, subcutaneous, perirenal, mesenteric, and omental tissue sites was studied in control and hypotensive animals. Lipolysis per millimole of triglyceride was found to be three to four times higher in mesenteric and omental fat cells than in adipocytes of the other sites sampled. The high lipolytic activity of mesenteric and omental adipocytes was partly attributable to their smaller cell size; however, lipolysis per cell was also higher. Hemorrhagic hypotension caused a 50-60% decrease in lipolytic activity at four of the five sites studied. Adipocytes of omental origin maintained their lipolytic activity at the prehypotensive level, however, indicating that the metabolic adjustments brought about by hemorrhagic hypotension are not uniform at all adipose tissue sites.