Rat cortical and trabecular bone collagen glycosylation are differently influenced by ovariectomy

This study sought to evaluate whether estrogen depletion influences the hydroxylysine glycosydes content of rat bone collagen. For this reason thirty 100 day old female rats were divided in 6 groups of 5 rats each. Three groups were ovariectomized and 3 groups were sham-operated. The animals were sacrificed at 115, 130 and 145 days of age (i.e., 15, 30 and 45 days after surgery). Cortical and trabecular bone was prepared from tibiae and femurs. Hydroxylysine glycosydes content was measured by HPLC. Ovariectomy is followed, in the rat, by an increased hydroxylysine glycosylation in trabecular bone but by a constant or slightly decreased hydroxylysine glycosylation in the cortical bone. In view of the different effects of estrogens on the two bone compartments previously reported, a possible functional explanation of these findings is proposed.