Effects of ovarian steroids on glucose metabolism in uterus horns isolated from underfed rats. Influence of castration

The effect of a restricted diet (50% of the normal intake) during 25 days, on the glucose metabolism was explored in uterus horn strips isolated from intact and ovariectomized rats. In intact underfed rats, the formation of ¹⁴CO₂ from U¹⁴C-glucose was significantly lower than in their controls. In castrated rats, the formation of ¹⁴CO₂ increased after underfeeding. The return to ad libitum feeding increased glucose metabolism in both groups. Total food deprivation for 4 days diminished ¹⁴CO₂ formation both in non-ovariectomized rats and in ovariectomized ones as measured at the end of this fasting period. This diminution was greater in intact rats. The increase of glucose metabolism provoked by the administration of s.c. estradiol, progesterone or their combination was more important in underfed intact animals. In intact rats, blood levels of endogenous estradiol and progesterone decreased as a result of underfeeding. In spayed ones, their low concentration increased in relation to their controls.