Immediate, short- and long-term opposite effects of oestradiol-17 beta on glucose metabolism in rat adipocytes: relationship with the biphasic changes in body weight and food intake.

The changes in the effects of oestradiol-17 beta on body weight, food intake and [1-14C]glucose oxidation in adipocytes were followed in sham-operated, ovariectomized and adrenalectomized-ovariectomized rats to eliminate effects of endogenous progesterone and corticosterone. During the first 5 days oestradiol induced a dramatic fall in food intake and body weight concomitant with a decrease in glucose oxidation by adipocytes, when tested 12 h and 3 days after the beginning of treatment. In-vitro incubations with oestradiol showed that this was a direct effect of this hormone. On the other hand, from days 5 to 14 of treatment, body weight and food intake increased, though they were still lower than in sham-operated controls. On day 14, as values of treated rats tended to reach those of controls, glucose oxidation in adipocytes was stimulated by oestradiol treatment. An insulin effect was still observable and none of these effects was dependent on the adrenal gland. These biphasic changes in the parameters studied could be closely related; moreover, a relationship with other oestradiol actions on metabolism that are known to be corticosterone-dependent could be eliminated.