GLUCOREGULATION DURING PROGRESSIVE STARVATION IN LATE PREGNANCY IN THE RAT

The response of glucose utilization (transport and phosphorylation) by individual skeletal muscles to progressive starvation in late pregnan cy in the rat was investigated in relation to changes in whole body gl ucose turnover. Compared with insulin-stimulated values, the decline i n muscle glucose utilization evoked by short-term (6-h) starvation was about twofold greater in pregnancy. Suppression of glucose utilizatio n by slow-twitch muscles was observed as the starvation period was ext ended from 6 to 24 h only in unmated rats. Extending starvation to 24 h did not further reduce glucose utilization by fast-twitch skeletal m uscles in either group. Suppression of whole body glucose disposal was observed between 6 and 24 h of starvation in unmated, but not pregnan t, rats. The results demonstrate that metabolic adaptation of almost c omplete suppression of glucose utilization by slow-twitch muscle, norm ally elicited only by prolonged (24-h) starvation, is already establis hed after acute (6-h) starvation in late pregnancy. The present study supports the concept of ''accelerated starvation'' in late pregnancy w ith respect to muscle glucose utilization after short-term food withdr awal but demonstrates that further glucose conservation cannot be achi eved after more prolonged starvation.