FIG. 6. .

Diet-induced vitamin D₃ deficiency is associated with a robust response to superovulation with exogenous gonadotropins. Representative photomicrograph (original magnification ×40) of WT (top) and Cyp27b1 null mice fed a Vit D₃-deficient diet during the peripubertal period (bottom), injected with saline or superovulated with eCG plus hCG. A) WT mice injected with saline. B) Cyp27b1 null mice fed a Vit D₃− diet, injected with saline. C) WT mice fed a Vit D₃+ diet, injected with eCG and hCG. D) Cyp27b1 null mice fed a Vit D₃− diet, injected with eCG and hCG. E) Number of oocytes deposited into the oviduct of WT and CYP27b1 null (KO) mice fed a Vit D₃+ diet and Cyp27b1 null mice fed a Vit D₃− diet after superovulation with eCG and hCG. AF, antral follicle; CL, corpus luteum; PA, early preantral; 2°, secondary. ^aP = 0.02 vs. WT and KO mice fed a Vit D₃+ diet during the peripubertal transition (n = 4–6).