Local regulation of lipolysis in adipose tissue by fatty acids, prostaglandins and adenosine.

From this review of the literature the following tentative conclusions may be drawn: 1) The relationship between cyclic AMP and lipolysis is not linear. In particular, only very small elevations of cyclic AMP appear to be necessary for essentially maximal lipolysis. One consequence of this is that some of the studies concerning feed-back regulation of cyclic AMP may not be relevant to our understanding of the regulation of lipolysis. 2) The only substances for which a firm role as feed-back regulators has been documented are free fatty acids. Their importance under in vivo conditions are, however, not settled. 3) The bulk of the present evidence fails to suggest a role for endogenous prostaglandins (and related compounds) as feed-back regulators of lipolysis. 4) There is considerable evidence that endogenous adenosine modulates lipolysis in vivo and in vitro. Adenosine does not appear to act as a feed-back regulator in the strict sense but the formation of adenosine may be enhanced under conditions of lipolysis because of simultaneously occurring breakdown of ATP.