Role of adipose tissue in free fatty acid metabolism in hemorrhagic hypotension and shock

Abstract

This study was designed to observe the effects of hemorrhage on the mobilization of free fatty acids from adipose tissue under a variety of experimental conditions. Experiments were conducted in fasting rabbits and dogs. A significant fall in arterial plasma free fatty acids was observed in rabbits following hemorrhage of 4 ml every 2 min and after inducing acute hemorrhagic hypotension. Dogs were hemorrhaged to a mean arterial blood pressure of 40 mm mercury. Adipose-tissue free fatty acids and arterial-plasma free fatty acids were simultaneously measured before and after hemorrhagic hypotension until death. Afterial free fatty acids fell significantly following hemorrhage, while the concentration of adipose-tissue free fatty acids rose significantly. In the next series of experiments, dogs were pretreated with an alpha-receptor blocking agent phenoxybenzamine and acutely hemorrhaged. The results showed a significant rise in arterial free fatty acids concentration and an insignificant increase in adipose-tissue free fatty acids. These results suggest that hypoperfusion of adipose tissue plays an important role in the decreased supply of a major body fuel following hemorrhagic hypotension. The results are compatible with the view that metabolic fuel failure may be an important factor in the development of the complications of acute hemorrhage and suggest the concept that adipose tissue may be an important target organ in hemorrhagic shock.