LEPR and obesity due to melanocortin 4 receptor deficiency: To evaluate whether obesity would further exacerbate the effects of ovariectomy on bone, we examined the tibiae and fourth lumbar (L4) vertebrae from leptin receptor-deficient female (Leprfa/fa) Zucker rats and their heterozygous lean controls (Leprfa/+) that were either sham-operated or ovariectomized (Ovx).