Lipolysis and adenosine 3'5'-cyclic monophosphate in adipose tissue of the New Zealand obese mouse; the activities of adipose tissue adenyl cyclase and phosphodiesterase.

Abstract

Cyclic 3′, 5′ nucleotide phosphodicsterase and adenyl cyclase were measured in homogenates prepared from isolated fat cells from obese (NZO/Bl) and normal mice. Young obese mice showed increased phosphodiesterase activity compared with controls. Older mice of both strains showed markedly diminished phosphodiesterase activity which, however, remained higher in tissue from the obese mice. — Adenyl cyclase activity was higher in tissue from both young and old obese mice than in tissue from controls of the same age. However, the adenyl cyclase activity observed in homogenates of tissue from control animals was insufficient to account for the rate of rise of cyclic AMP in the intact tissue. — It is proposed that the increased phosphodiesterase activity in young obese mice accounts for the decreased cyclic AMP levels observed earlier in isolated fat cells.