EFFECTS OF OVARIECTOMY AND EXERCISE TRAINING ON MUSCLE GLUT4 CONTENT AND GLUCOSE-METABOLISM IN RATS

The present study examined the effects of 6 wk of ovarian endocrine de ficiency on skeletal muscle GLUT-4 glucose transporter protein and glu cose transport activity in sedentary and endurance-trained rats. Femal e Wistar rats (10 wk old) underwent bilateral ovariectomy (OVX) or sha m surgery followed by a 5-wk swim-training protocol. OVX resulted in n o significant changes in glycogen or GLUT-4 glucose transporter concen tration in the soleus, epitrochlearis, or flexor digitorum brevis (FDB ) muscles or in basal and maximally insulin-stimulated 2-deoxy-D-[1,2- H-3] glucose (2-[H-3]DG) transport in the soleus or epitrochlearis, su ggesting that moderate-duration ovarian hormone deficiency does not si gnificantly impair insulin action in skeletal muscle. In contrast, OVX decreased the maximal activation of 2-[H-3]DG transport in the FDB by in vitro electrical stimulation. OVX had no significant effect on the training-induced changes in oxidative enzyme activities, GLUT-4 prote in expression, glycogen content, or insulin-stimulated 2-[H-3]DG trans port in the soleus or epitrochlearis. These findings provide the first evidence that ovarian hormone deficiency decreases contraction-stimul ated glucose transport in skeletal muscle.