INS and polycystic ovary syndrome: Insulin acts as a co-gonadotropin [79] and stimulates the effects of LH [80,81] on androgen biosynthesis in ovarian theca cells by inducing cytochrome P450c17 expression, which influences 17-hydroxylase and 17,20-lyase activity [56], making theca cells in women with PCOS more sensitive to the hyperandrogenic effects of insulin in contrast to healthy women [82].