Delta opioid receptors mediate glucose uptake in skeletal muscles of lean and obese-diabetic (ob/ob) mice

Specific binding sites for [I-125]beta -endorphin and the partial derivative (1)-opioid [H-3][D-pen(2), D-pen(5)]enkephalin (DPDPE) were quantified using autoradiography in soleus and extensor digitorum longus (EDL) muscles of lean and obese-diabetic (ob/ob) mice. The density of binding was significantly higher in obese-diabetic than lean mice. The uptake of 2-deoxy-D-[1-H-3]deoxyglucose, a nonmetabolized glucose analogue, into isolated soleus and EDL muscles was stimulated by beta -endorphin, beta -endorphin 1-27, and DPDPE, but not by the partial derivative (2)-opioid deltorphin II. Both beta -endorphin and DPDPE stimulated deoxyglucose uptake in obese-diabetic mice. Thus, glucose transport in skeletal muscle may be partly mediated via partial derivative (1)-opioid receptors. The increased receptor density in obese-diabetic mice may be an adaptive response.