[Effect of pamidronate on bone blood flow and serum levels of IGF-I in sham-operated and oophorectomized female rats].

Abstract

In our previous work [7] we demonstrated that the bisphosphonate pamidronate lowered the bone blood flow of non-castrated female rats and inhibited the increase in bone blood flow after oophorectomy (OOX). In this paper we present the results of two similar experiments but also with the estimation of IGF-I in blood. The blood flow in the bones of female rats was estimated by means of 85-Sr microsphere technique (NEN, USA), the blood level of IGF-I was ascertained with Rat IGF-I RIA Kit (DSL, USA). Both experiments A and B were performed on female rats according to the same experimental scheme: group I--sham-operated controls, group II--OOX (four weeks before the experiment), group III--pamidronate (Aredia, CIBA-Giegy, 0.6 mg i.p. three days in the week, for four weeks), group IV--OOX + pamidronate. The results of both experiments can be summarized as follows:--it was confirmed again that OOX rises the circulatory indicators in the bones as well as the blood level of IGF-I;--pamidronate suppresses the increase in bone blood flow after OOX;--pamidronate does not unequivocally influence the level of IGF-I in blood. Thus, it is very probable that IGF-I plays a role in the increase of bone blood flow after OOX. However, it is still not clear how the deficiency of estrogens influences the blood level of IGF-I. The mode of action of pamidronate on the bone blood flow--mainly elevated after OOX--is not clear as well.