APPL2 and polycystic ovary syndrome: The data of the present work indicate that oral MTF treatment in the group of women with IR increased APPL1 and reduced APPL2 levels in the endometrial tissue of these women, independent of their PCOS condition, indicating an insulin-sensitizing action of MTF through adiponectin signaling, probably favoring the insulin-sensitizing endogen action of adiponectin in the cells.