title: Effects of hysterectomy on bone in intact rats, ovariectomized rats, and ovariectomized rats treated with estrogen.
abstract: To determine whether the uterus plays any role in mediating the ability of estrogen to conserve bone in the rat, eight groups of animals (n = 8) with their skeletons labeled with 45Ca were studied. Rats were ovariectomized (OVX), hysterectomized (Hyst), or given sham operations (Sham) and then pair-fed a low-hydroxyproline casein diet for 4 weeks. The groups were treated orally with 17 beta-estradiol (E2) or vehicle, and serial measurements of biochemical markers of bone breakdown were made in weeks 1, 2, and 4. The femur density was measured by dual-energy X-ray absorptiometry (DXA), and skeletal calcium and 45Ca content were determined chemically. Final total body calcium values (mg) in the eight treatment groups were (means +/- SD): Sham, 2573 +/- 179; Sham + E2, 2635 +/- 159; Hyst, 2537 +/- 151; Hyst + E2, 2410 +/- 151; OVX, 2189 +/- 146; OVX + E2, 2559 +/- 172; OVX/Hyst, 2138 +/- 132; and OVX/Hyst + E2, 2460 +/- 140. Ovariectomy raised biochemical markers of bone resorption (urinary 45Ca, hydroxyproline, and deoxypyridinoline), lowered DXA bone mineral density, and reduced total body calcium and 45Ca content in both Hyst and Sham-Hyst animals (p < 0.001), whereas E2 treatment prevented these changes. Hysterectomy did not impair the ability of E2 to conserve bone in OVX rats. Thus, we conclude that estrogen-mediated induction of growth factors from uterine tissue does not play an essential role in mediating the bone-conserving actions of estrogen in the rat.
authors.affiliation: Department of Medicine, University of Otago, Dunedin, New Zealand.
authors.forename: A
authors.initials: A
authors.lastname: Goulding
authors.forename: E
authors.initials: E
authors.lastname: Gold
authors.forename: N J
authors.initials: NJ
authors.lastname: Lewis-Barned
mesh_terms: D000818:Animals; D001685:Biological Factors / Q000502:physiology; D001842:Bone and Bones / Q000503:physiopathology*; D004353:Drug Evaluation, Preclinical; D004958:Estradiol / Q000627:therapeutic use*; D015914:Estrogen Replacement Therapy; D005260:Female; D007044:Hysterectomy / Q000009:adverse effects*; D010024:Osteoporosis / Q000188:drug therapy*; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013268:Stimulation, Chemical; D014599:Uterus / Q000502:physiology*
chemical_list: D001685:Biological Factors; D004958:Estradiol