Effects of a restricted diet on in vitro spontaneous activity and glucose metabolism in isolated rat uterus. Influence of castration.

The effects of a restricted-diet (50% of the normal intake during 25 d) on the isometric developed tension (IDT), the metabolism of labelled glucose, and the levels of glycogen, of uteri isolated from ovariectomized (25 d) and non-ovariectomized rats were explored. The restriction of food intake produced a fall in the contractile activity of normal, non-ovariectomized, rats in permanent diestrous compared to normally fed rats in diestrous. On the contrary, in castrated rats, the IDT of isolated uterus from underfed rats, was significantly higher than its normal-fed controls. In normal rats the formation of 14CO2 from U 14C-glucose was significantly lower in uterine preparations from restricted-diet animals than the control one. On the other hand, in castrated rats, the formation of 14CO2 increased as a result of underfeeding. The post-incubation levels of glycogen in uteri from normal-fed animals diminished significantly in comparison to 0 time values. In uteri from rats subjected to a dietary restriction, the initial glycogen values were lower than in normal-fed controls, but they did not decline further after incubation in KRB medium. On the contrary, even when the levels of glycogen were significantly lower at 0 time than in diestrous animals, they diminished in ovariectomized rats after incubation, no matter the diet. The above results indicate that the effects of restricted-diet on contractile activity, levels of glycogen and glucose metabolism were not observed in ovariectomized rats. Further researches are needed to clarify that point.