Sex differences in the metabolic dysfunction and insulin resistance of skeletal muscle glucose transport following high fructose ingestion

The role of high fructose ingestion (HFI) in the development of conditions mimicking human metabolic syndrome has mostly been demonstrated in male animals; however, the extent of HFI-induced metabolic alterations in females remains unclear. The present study investigated whether HFI-induced metabolic perturbations differ between sexes and whether HFI aggravates the metabolic disturbances under ovarian hormone deprivation. Male, female, and ovariectomized (OVX) Sprague-Dawley rats were given either water or liquid fructose (10% wt/vol) for 6 wk. Blood pressure, glucose tolerance, insulin-stimulated glucose transport activity and signaling proteins, including insulin receptor (IR), insulin receptor substrate 1 (IRS-1), Akt, Akt substrate of 160 kDa (AS160), AMPK alpha, JNK, p38 MAPK, angiotensin-converting enzyme (ACE), ANG II type 1 receptor (AT(1)R), ACE2, and Mas receptor (MasR) in skeletal muscle, were evaluated. We found that HFI led to glucose intolerance and hypertension in male and OVX rats but not in female rats with intact ovaries. Moreover, HFI did not induce insulin resistance in the skeletal muscle of female and OVX rats but impaired the insulin-stimulated glucose transport activity in the skeletal muscle of male rats, which was accompanied by lower insulin-stimulated IRS-1 Tyr(989) (44%), Akt Ser(473) (30%), and AS(160) Ser(588) (43%), and increases in insulin-stimulated IRS-1 Ser(307) (78%), JNK Thr(183)/Tyr(185) (69%), and p38 MAPK Thr(180)/ Tyr(182) (81%). The results from the present study show sex differences in the development of metabolic syndrome-like conditions and indicate the protective role of female sex hormones against HFI-induced cardiometabolic abnormalities.