Inhibition of Adenosine 3′,5′-Monophosphate Accumulation and Lipolysis by Adenosine Analogs in Human Subcutaneous Adipocytes*

Abstract

Lipolysis and cAMP accumulation were inhibited by low concentrations of adenosine and its analogs in human sc adipocytes stimulated by 2 microM DL-isoproterenol. The order of potency of the adenosine analogs tested was N6-(phenylisopropyl)adenosine greater than 2-chloroadenosine greater than 5'-N-ethylcarboxamidoadenosine greater than adenosine greater than 2',5'-dideoxyadenosine greater than 2'-deoxyadenosine. Inosine was without effect. No stimulation of cAMP accumulation by 5'-N-ethylcarboxamidoadenosine was observed. These results strongly suggest the presence of inhibitory adenosine Ri- and P-sites and the absence of stimulatory Ra-sites in human sc adipocytes.