Prostaglandin E2 action and binding in human adipocytes: effects of sex, age, and obesity.

The antilipolytic effect of prostaglandin E2 (PGE2) was studied in subcutaneous human adipocytes. The influence of sex, age, and obesity on the PGE2 effect was investigated. The antilipolytic effects of PGE2 were related to the PGE2 binding data obtained in the same adipocytes. The maximal antilipolytic action of PGE2 was slightly reduced in adipocytes in males compared with females (maximal inhibition 86% v 97%, P greater than .05). The PGE2 binding was similar in adipocytes in females and males. The antilipolytic effect of PGE2 and the PGE2 binding was similar when young females were compared with older females. However, the antilipolytic effect of PGE2 was significantly reduced in obese compared with nonobese subjects. If lipolysis was only stimulated by adenosine deaminase, the sensitivity of PGE2 was reduced in obesity (IC50, 1.45 nmol/L v 0.47 nmol/L, P less than .01), but the maximal antilipolytic effect of PGE2 in the two groups was similar, with an inhibitory effect of 95% to 98%. If lipolysis was stimulated by both adenosine deaminase and theophylline (2 mmol/L), it was especially the maximal antilipolytic effect of PGE2 that was impaired in adipocytes from obese subjects (lipolysis was maximally inhibited by 61% v 92%, P less than .01). When the PGE2 binding was expressed in relation to adipocyte surface area, the total binding capacity (Bmax) was reduced in adipocytes in obese subjects from 26.5 to 17.9 fmol/100 cm2 (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)