To test this hypothesis , we used ovariectomized rats as a model of postmenopausal osteoporosis to examine the deleterious effects of Cd on bone with and without added P. Fifty @-month-old ovariectomized Sprague-Dawley rats were assigned to five treatment groups ( n = @ per group ) for @ months as follows : ( @ ) control ; ( @ ) @ ppm Cd ; ( @ ) @ ppm Cd plus @ % P ; ( @ ) @ ppm Cd ; and ( @ ) @ ppm Cd plus @ % P.