ANTI-LIPOLYTIC EFFECTS OF BETA-HYDROXYBUTYRATE

The addition of β-hydroxybutyrate to epididymal fat incubated in vitro reduced the production of glycerol and free fatty acids. Inhibition of lipolysis was maximal (∼ 30%) when physiologic concentrations of β-hydroxybutyrate (0.1 mg./ml.) were added to tissues obtained from fasting rats. At a concentration of 10 mg./ml., β-hydroxybutyrate also abolished lipolysis in response to 0.05 μg./ml. epinephrine and severely reduced the lipolytic effects of ACTH (1 μg./ml.), TSH (25 mU/ml.) and glucagon (10 μg./ml.). Increasing the concentration of epinephrine produced a progressive but significantly lesser lipolytic response in β-hydroxybutyrate treated (10 mg./ml.) than in control tissues. β-hydroxybutyrate, 10 mg./ml., abolished the lipolytic response to theophylline (0.54 mg./ml.), but did not inhibit the lipolytic response to exogenous cyclic adenosine 3′,5′-monophosphate (CAMP) in the presence of theophylline. These results are consistent with the concept that β-hydroxbutyrate may modulate the production of fatty acids during fasting and suggest that the antagonism of epinephrine-induced lipolysis may result from inhibition of CAMP formation in adipose tissue. © 1969.