Figure 5. Estrogen receptor-α mediates the protective effects of estrogen on weight gain and mammary gland inflammation.

A, Study schema. At 5 wks of age, ovary intact mice and mice that had been subjected to ovariectomy (OVX) were fed either low fat (LF) or high fat (HF) diets. The ovary intact wild type mice were fed LF or HF diets for 10 wks until sacrifice (n=10/gp). The OVX mice were fed HF diet for 10 wks (n=10). The last group of ovary intact mice was homozygous for deletion of ERα (ERα knockout) and was fed HF diet for 10 wks. B, Body weight was monitored weekly in the different treatment groups. Weight gain in ERα KO mice mimicked the weight gain observed in OVX mice. C, Calorie consumption was monitored weekly. D, In pair-wise comparisons, at sacrifice, HF OVX and HF + ERα KO mice had greater body weights (*, P<0.001), MG inflammation (CLS/cm²; *, P<0.001), and MG adipocyte diameter (*, P<0.001) than HF mice.