Journal ArticleDOI
The effect of different hormone replacement therapy regimens on the mechanical properties of rat vertebrae.
Debbie Chachra,Debbie Chachra,M. Kasra,M. Kasra,Carla M. Vanin,Neil J. MacLusky,Robert F. Casper,Marc D. Grynpas,Marc D. Grynpas +8 more
Reads0
Chats0
TLDR
It is found that all three estrogen/progestin regimens maintain bone density and all mechanical properties at a level indistinguishable from the control, however, the cyclic and continuous NET treatment results were, with the exception of density, also indistinguishable from those of the ovariectomized group.Abstract:
The purpose of this study was to examine the effects of estrogen replacement, in concert with three different progestin regimens, on the mechanical properties of rat lumbar vertebrae. Ninety-two Sprague-Dawley rats (11 months old) were divided into six groups for treatment. The first group was an intact control, the second group (OVX) was ovariectomized only, and the third group (estrogen-only) was ovariectomized and received continuous estrogen through a 17 beta-estradiol implant. The remaining groups were ovariectomized and received estrogen and progestin (norethindrone, NET) therapy; 3 micrograms of NET was injected daily (estrogen plus continuous NET), or 6 micrograms of NET was injected for 14 consecutive days of a 28-day cycle (estrogen plus cyclic NET), or for 3 consecutive days of a 6-day cycle (estrogen plus interrupted NET). The animals were sacrificed after 6 months, and the vertebrae were dissected out. The vertebral processes of the fourth lumbar vertebrae were removed, and the density of the vertebral bodies was determined. They were then subjected to compression testing. We found that all three estrogen/progestin regimens maintain bone density and all mechanical properties at a level indistinguishable from the control. However, the cyclic and continuous NET treatment results were, with the exception of density, also indistinguishable from those of the ovariectomized group. The estrogen plus interrupted NET group on the other hand, has a significantly greater compressive modulus and density than the ovariectomized group. In conclusion, with respect to the ovariectomized group, the estrogen plus interrupted NET treatment resulted in a superior density and compressive modulus.(ABSTRACT TRUNCATED AT 250 WORDS)read more
Citations
More filters
Journal ArticleDOI
Evidence of estrogen receptors in normal human osteoblast-like cells
Erik Fink Eriksen,Douglas S. Colvard,Nicholas J. Berg,Mark L. Graham,Kenneth G. Mann,Thomas C. Spelsberg,B. Lawrence Rlggs +6 more
TL;DR: The data suggest that estrogen acts directly on human bone cells through a classical estrogen receptor-mediated mechanism, indicating an induction of functional progesterone receptors.
Journal ArticleDOI
Standardized bending and breaking test for the normal and osteoporotic metaphyseal tibias of the rat: effect of estradiol, testosterone, and raloxifene.
E.K. Stürmer,Dana Seidlova-Wuttke,Stephan Sehmisch,T. Rack,Joern Wille,K.-H. Frosch,Wolfgang Wuttke,Klaus Michael Stürmer +7 more
TL;DR: A highly sensitive three‐point bending test for the metaphyseal tibias in rats to evaluate stiffness and strength was developed and validated in a right‐left comparison and a bioassay with soy‐free food, estradiol, raloxifene, and testosterone in orchidectomized rats.
Journal ArticleDOI
Effects of the steroidal aromatase inhibitor exemestane and the nonsteroidal aromatase inhibitor letrozole on bone and lipid metabolism in ovariectomized rats.
TL;DR: EXE and 17-H-EXE significantly prevent bone loss, enhance bone mechanical strength, and lower serum cholesterol and low-density lipoprotein levels in OVX rats, and these protective effects on end-organ function are not seen with the nonsteroidal inhibitor LET.
Journal ArticleDOI
The steroidal aromatase inhibitor exemestane prevents bone loss in ovariectomized rats.
Paul E. Goss,S Qi,Robert G. Josse,Kenneth P.H. Pritzker,Kenneth P.H. Pritzker,M Mendes,H Hu,Stephen D. Waldman,Marc D. Grynpas,Marc D. Grynpas +9 more
TL;DR: The positive results of EXE on bone and lipid metabolism in the OVX rat model merit further investigation of the effects of exemestane in postmenopausal women.
Journal ArticleDOI
Early Estrogen Replacement Therapy Reverses the Rapid Loss of Trabecular Bone Volume and Prevents Further Deterioration of Connectivity in the Rat
TL;DR: It is demonstrated that ERT can restore the lost trabecular bone, but not trabECular connectivity, that occurs soon after OVX by allowing bone formation to continue in previously activated bone remodeling units while suppressing the production of new remodelingunits.
References
More filters
Journal ArticleDOI
The Aged Rat Model of Ovarian Hormone Deficiency Bone Loss
TL;DR: The aged rat model of ovarian hormone deficiency bone loss qualifies for serious consideration as a practical convenient cost-effective animal model for exploring aspects of the pathogenesis and treatment of postmenopausal bone loss.
Journal Article
Estrogen replacement therapy I: a 10-year prospective study in the relationship to osteoporosis.
TL;DR: It is suggested that ERT could effectively reduce loss of bone mass associated with the postmenopausal state especially when administered within 3 years of LMP; it also confirmed David et.
Journal ArticleDOI
Progesterone as a bone-trophic hormone.
TL;DR: Critical analysis of the reviewed data indicate that progesterone meets the necessary criteria to play a causal role in mineral metabolism and provides the preliminary basis for further molecular, genetic, experimental, and clinical investigation of the role(s) of progestersone in bone remodeling.
Journal ArticleDOI
Time course of vertebral osteopenia in ovariectomized rats.
TL;DR: The results indicate that osteopenia and increased bone turnover occur in the lumbar vertebral bodies of OVX rats, as had been previously observed in the proximal tibial metaphyses of these animals.
Journal ArticleDOI
Oestrogen replacement therapy for prevention of osteoporosis after oophorectomy.
TL;DR: Mestranol in this dosage appeared to be relatively safe, but it is too early to evaluate the long-term hazards of such therapy.