C-13-GLYCOGEN DEPOSITION DURING PREGNANCY IN THE RAT FOLLOWING ROUTINE MEAL FEEDING

In vivo C-13-NMR was employed to determine the hepatic fate of infused [1-C-13]-D-glucose (200 mg/kg) following ad libitum or routine meal f eeding (RMF) regimes imposed during pregnancy. Hepatic glycogen synthe sis was measured immediately following the last meal in virgin, 10 and 20 day pregnant rats. No detectable incorporation of C-13-glucose int o glycogen was observed in 20 day pregnant and control fed virgin rats . In 20 day pregnant RMF rats, glycogen synthesis from C-13-glucose oc curred at a linear rate of 0.10/s (S.D. 0.018/s). By 50 min post-infus ion, C-13-glycogen levels were 131% (p < 0.01) higher than those seen for the 22 h starved and 2 h refed virgin group. Following 10 days of gestation, glucose incorporation into glycogen was maximal in both the ad libitum and RMF groups, Compared with the 20 day pregnant RMF grou p, the 10 day pregnant ad libitum and RMF rats produced 146% (p < 0.00 1) and 315% (p < 0.001) more incorporation of C-13-glucose into the gl ycogen macromolecule, respectively, Hepatic glycogen values were simil ar for both 10 and 20 day pregnant ad libitum rats (65.7 +/- 4.7 and 5 8.8 +/- 4.5 mg/g weight) but lower in the RMF groups by 58% and 48%, r espectively. In conclusion, meal feeding regimes in the pregnant rat a lter carbohydrate control of the liver producing increased glycogen sy nthesis initially via direct incorporation of glucose into the macromo lecule. (C) 1998 Elsevier Science B.V.