초록
본 연구는 폐경 후 여성에게 식이 칼슘염 형태, 에스트로겐 및 에스트로겐/칼슘 혼합요법이 골대사의 생화학적 변화에 미치는 영향을 알아보고자 난소절제쥐를 이용한 총 9군으로 분류하여 6주간 사육한 후 그 효과를 살펴보았다. 식이 섭취량, 식이 효율 및 체중 증가량은 난소절제로 현저히 증가하였으나 난소절제 후 estrogen 투여군 모두에서 식이 섭취량이 크게 감소되었다. 골흡수의 지표로 사용되는 소변으로 배설되는 hydroxyproline 함량은 난소절제로 현저히 증가하였으나, 난소절제 후 estrogen 투여군 모두에서 감소하였는데, 특히 estrogen/칼슘 혼합 투여군에서 가장 많은 감소를 나타내었다. 혈장 부갑상선 호르몬 함량은난소절제로 다소 증가하나, 난소절제 후 estrogen 및 estrogen/칼슘 혼합군에서 혈장 중 부갑상선 호르몬 수준이 32%나 감소되었다. 그러나 estrogen 점진적 감소군에서는 현저한 감소를 나타내지 않았다. 골생성 및 조골세포형성의 지표인 osteocalcin 함량과 AP 활성은 난소절제로 현저히 증가하였으나, 난소절제 후 estrogen 투여군 모두에서 감소하였다. 이상의 성적으로 보아 estrogen 및 estrogen/칼슘 혼흔합요법은 골교체율을 감소시켜 골손실을 방지하는데 효과적인 방안임을 확인할 수 있었으며, 한편 estrogen 점진적 감소요법은 골손실 감소에 크게 기여하지 못하나, estrogen점진적 감소와 고칼슘 투여군, estrogen 점진적 감소와 칼슘 점진적 증가군에서는 골손실을 상당량 방지할 수 있음을 알 수 있었다. 칼슘염 종류에 따른 골손실에 미치는 생화학적 요인들의 변화는 크게 나타나지 않았다.
This study was implemented in order to investigate the effects of dietary calcium-salt, estrogentreatment, and estrogen/calcium treatment on bone metabolism. Ovariectomized rats were used as animal models. Female Sprague-Dawley rats with a body weight of 250~280g were underwent ovariectomy or sham-operation. The ovariectomized rats were divided into 9 different experimental groups including the saline-treated group, the estrogen-treated group, the high calcium salt-treated group, and the estrogen/calcium treated groups and fed for 6 weeks. Creatinine and hydroxyproline in urine were analyzed. Creatinine, calcitonin, osteocalcin, alkaline phosphatase and parathyroid hormone in plasma were also determined. The results of the experiment are as follows : The ovariectomy caused a significant increase in the level of food intake, food effciency ratio and body weight gain in comparison with sham-operation. The overall food intake, food effciency ratio and body weight gain were significantly decreased by estrogen. The ovariectomized animals developed obesity as a result of increased food intake. In addition, estradiol injections suppressed food intake with a concomitant loss in body weight. The level or urinary hydroxyproline, as an indicator or bone resorntion, was higher in the ovariectomized rats compared to sham-opertion, while these decresed in the estrogen/calcium treated group. Parathyroid hormone and calcitonin in the plasma, that were used as the indicator of calcium homeostasis, parathyroid hormone higher in the ovariectomized rats compared to sham-operation. It was lowered by estrogen and high calcium treated groups; thus, estrogen and estrogen/calcium treated groups were decreased by 32% compared to saline treated group. Osteocalcin and alkaline phosphatase which are indicators of bone formation, were significantly higher in ovariectomized group, while this showed to be decreased in the estrogen and the ostrogenicalcium treated groups. Estrogen and estrogen/calcium in ovariectomized rats resulted in lower bone loss. However, estrogen treated group its gradual reduction showed little effect on bone loss, while the gradual reduction of estrogen had a preventive effect on bone loss when the treatment was combined with calcium intensification.