17β-Estradiol and Tamoxifen Prevent the Over-Glycosylation of Rat Trabecular Bone Collagen Induced by Ovariectomy

Abstract

Summary:We have recently demonstrated that ovariectomy in the rat causes over-glycosylation of collagen which is restricted to trabecular bone. In order to obtain further evidence, we studied whether estrogen or tamoxifen treatment prevented over-glycosylation of trabecular bone collagen. Forty one-hundred-day-old female rats were subjected to ovariectomy (n = 30) or sham-operation (n = 10). Starting the day of the operation, sham-operated rats were treated with vehicle, while ovariectomized rats were divided into three groups and treated with vehicle (n = 10), estrogen (n = 10) or tamoxifen (n = 10). Five rats from each group were sacrificed at 115 and 145 days of age. Femurs and tibiae were separated into cortical and trabecular bone, demineralized, hydrolyzed and analyzed by HPLC for hydroxylysine glycosides and hydroxyproline content. Hydroxylysine glycoside content was expressed as a molar ratio with hydroxyproline. The results can be summarized as follows: 1) cortical bone collagen glycosylation did not vary among the different groups;2) over-glycosylation of trabecular bone collagen observed in the ovariectomized rats was prevented by the administration of either 17ß-estradiol or tamoxifen.These data demonstrated that estrogens affect glycosylation of trabecular bone collagen.

Mechano-regulation of collagen biosynthesis in periodontal ligament

“…It has been reported that collagen glycosylation may contribute to structural and biological functions, such as control of collagen fibrillogenesis [84-87], collagen cross-linking [37,88,89] and collagen-cell interaction [90,91]. It has been reported that altered collagen glycosylation is associated with bone disorders, such as osteogenesis imperfecta [92-94], postmenopausal osteoporosis [95,96] and osteosarcoma, osteofibrous dysplasia [97], suggesting the significant roles of collagen glycosylation in mineralization. The most predominant glycosylated site of type I collagen, α1/2 Hyl-87, is one of the major helical cross-linking sites [98,99].…”

Lysyl Hydroxylase 3-mediated Glucosylation in Type I Collagen

“…In bone, type I collagen is relatively less glycosylated (15,26,27); however, in bone/skeletal disorders, such as osteogenesis imperfecta (20, 28 -30), postmenopausal osteoporosis (19,23,31,32), osteosarcoma, osteofibrous dysplasia (21), and Kashin-Beck disease (33), altered collagen glycosylation occurs, and this has been implicated in mineralization defects. Due to the structure of the carbohydrates and the glycosylation sites, structural as well as biological functions have been proposed for collagen glycosylation (i.e.…”

Lysyl Hydroxylase 3 Glucosylates Galactosylhydroxylysine Residues in Type I Collagen in Osteoblast Culture

“…It has been reported that altered collagen glycosylation is associated with bone disorders (35)(36)(37)(38)(39)(40)(41)(42). However, the role of LH3 in type I collagen modification and bone biology has not been investigated.…”