In vitro studies on collagen metabolism in metaphyseal rat bone. A. The effect of pre-treatment with oestradiol-17 beta.

The effect of oestradiol-17 beta treatment on bone collagen metabolism in vitro was studied in metaphyseal rat bone. Rats were oophorectomized and subsequently treated for 3 weeks with different doses of oestradiol-17 beta. Bone pieces were incubated in a modified Krebs-Ringer bicarbonate medium for 6 h. Synthesis of (14c)hydroxyproline from (14C)proline and the incorporation of this amino acid into the bone samples was determined and the collagen synthesis and accretion rates calculated from these data. Collagen resorption rates were calculated from measured release of non-radioactive hydroxyproline to the medium. Castration resulted in an increased rate of accretion and resorption of collagen. All doses of oestradiol tested in this study (1 to 20 mug per animal per day for 3 weeks) decreased both accretion and resorption rates to levels insignificantly different from those of the non-castrated control rats. Only the 2 mug treated group had significantly better collagen balance than the castrated untreated rats.