Different effect of a restricted diet on isolated uteri of ovariectomized and non-ovariectomized rats. Influence of indomethacin and prostaglandins

The effect of restricted diet (50% of the normal intake during 25 days) on the metabolism of labelled glucose, in uteri isolated from ovariectomized (25 days) and non-ovariectomized rats, was explored. In intact rats subjected to dietary restriction, the formation of ¹⁴CO₂ from U ¹⁴C-glucose is significantly lower than in controls. Indomethacin increases glucose metabolism, being even higher in underfed rats' uteri. This effect is not altered by the addition of prostaglandins E₁, E₂ or F_2α to the medium. In castrated rats, the formation of ¹⁴CO₂ increases due to underfeeding and this result is not altered by indomethacin. Glycogen and triglyceride values in the isolated uterus were measured immediately after killing (O time) and after 60 min of incubation in a glucose-free KRB medium. The post-incubation levels of glycogen from intact normal fed animals diminshed in comparison to initial values, and this result was not altered by the addition of indomethacin. In rats subjected to dietary restriction, glycogen did not decline further after incubation, and the addition of indomethacin led to a significant fall. In spayed rats, glycogen diminished after 60 min both in normal fed rats and in underfed ones, and they were not affected by the indomethacin. In intact underfed rats, uterine triglycerides fall after 60 min. Indomethacin changes this situation, which is again evoked by the addition of PGF_2α. In ovariectomized rats, uterine triglycerides are neither altered by a restricted diet nor affected by indomethacin. These results indicate that the effects of a restricted diet on glucose and triglyceride metabolisms in the isolated uterus of intact rats does not appear in ovariectomized ones.