Aim
This study was conducted to investigate the effects of sex hormone-binding globulin (SHBG) on glucose metabolism and insulin resistance in human placental trophoblasts and involvement of the cAMP/PKA/CREB1 signaling pathway in these effects.
Conclusion
Sex hormone-binding globulin regulates GLUT1 expression via the cAMP/PKA/CREB1 pathway and affects glucose transport in the placenta, which can induce insulin resistance and gestational diabetes.
Methods
An insulin resistance cell model of human trophoblasts was established. An SHBG-overexpression plasmid was transfected into these cells, and the expression of glucose transporter 1 (GLUT1), CREB and p-CREB was detected and analyzed in normal cells, model cells and all groups of transfected cells by real-time PCR and western blotting; cAMP, PKA, glucose consumption and pyruvic acid levels were also detected.
Results
Among the four groups, there was no significant difference in the expression of CREB mRNA or GLUT1 mRNA (P > 0.05); however, CREB, p-CREB, GLUT1 protein, cAMP and PKA showed low expression (P < 0.05) and cell glucose consumption and pyruvate production were decreased (P < 0.05) in the model group, compared to the normal group. SHBG overexpression in insulin-resistant cells partially increased the levels of p-CREB, GLUT1, cAMP and PKA (P < 0.05). Intracellular glucose consumption and pyruvate production were nearly restored to the levels observed in cells from the normal group.