Growth hormone normalizes vertebral strength in ovariectomized rats.
Ten-month-old lactating breeders were ovariectomized and kept on a low calcium diet. One month after ovariectomy, the rats were dosed once daily for 6 months with either a low dose of growth hormone (GH) (0.05 mg), a high dose of GH (1 mg), estrogen plus gestagen (E-G) [17 beta-estradiol (0.1 mg); norethisterone-acetate (0.05 mg)], or a combination of GH and E-G. Mechanical competence, apparent dry density, apparent ash density and ash concentration were measured in the fourth lumbar vertebral body. The reduced mechanical strength, ash density and ash concentration found in the vertebral body of ovariectomized animals were prevented by the high dose of GH alone, or in combination with E-G. E-G alone partly prevented the decline in ash density and ash concentration, but did not affect the reduced mechanical strength seen after ovariectomy. Only minor effects were observed after treatment with the low dose of GH, alone or in combination with E-G. In conclusion this study shows that GH administration prevents the decline in mechanical strength and bone mineral density seen in rats after ovariectomy.
Eschen
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Department of Growth Hormone Biology, Novo-Nordisk A/S, Gentofte, Denmark.
Andreassen
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D000818:Animals; D001835:Body Weight / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects*; D001851:Bone Diseases, Metabolic / Q000188:drug therapy*; D004195:Disease Models, Animal; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D008159:Lumbar Vertebrae / Q000187:drug effects* / Q000502:physiology; D009640:Norethindrone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000077563:Norethindrone Acetate; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013718:Tensile Strength / Q000187:drug effects
D004958:Estradiol; D013006:Growth Hormone; D000077563:Norethindrone Acetate; D009640:Norethindrone