The Effect Of Ovarian Status, Form Of Vitamin-D3 Steroid And Calcium Supplementation On Bone Metabolism In The Rat And The Quail

Degenerative bone conditions such as osteoporosis affect the elderly population by causing skeletal fractures. The incidence of osteoporosis is far greater in postmenopausal women and therefore, loss of ovarian function, leading to estrogen deficiency, plays an important role in the development of this disease. Abnormal vitamin D metabolism and insufficient dietary calcium may also contribute to the development of osteoporosis. Three experiments were conducted to investigate the effects of estrogen supplementation and dietary vitamin D 3 steroids or calcium supplementation on skeletal metabolism. Eight week old ovariectomized (Ovx) or sham operated Sprague-Dawley rats or aged anovulatory Coturnix quail hens were used as animal models. Feeding a diet containing 1,25(OH) 2 D 3 (5μg/kg) with 0.2% calcium was as effective in maintaining bone mineral concentrations as 20μg/kg vitamin D 3 and 1.0% calcium. However, both bone calcium and zinc concentrations were decreased in Ovx rats and anovulatory quail fed 1,25(OH) 2 D 3 and low calcium. Estrogen supplementation to Ovx rats and anovulatory quail fed 1,25(OH) 2 D 3 and 0.2% Ca increased mineral concentrations, thus suggesting enhanced skeletal integrity. Therefore, these studies suggest improved skeletal calcification in control and estrogen supplemented female rats and quail fed 1,25(OH) 2 D 3 and 0.2% calcium versus vitamin D 3 with 1.0% calcium.