LHB and Infertility: Our results, combined with the results of these previous studies, converge on a model in which derepression of Zeb1 is the driving cause of infertility associated with loss of miR-200b/429, and more generally, that miR-200a/b limits Zeb1 expression in pituitary gonadotrope cells to promote Lhb expression and ovulation (Fig. 5).