Possible participation of prostaglandins in the increase in the bone blood flow in oophorectomized female rats.

The aim of this study was to verify the possible role of prostaglandin (PG) in the increase in the bone blood flow of female rats after oophorectomy (OOX). In two experiments we determined blood flow in the tibia and distal femur (85Sr-microspheres) and 24-h incorporation of 45Ca and 3H-proline. Acetylosalicyclic acid (ASA, 0.13% in the food for 4 weeks) was used to suppress the production of PG. There was an increase in the bone blood flow after OOX (performed 4 weeks prior to the experiment), no change after ASA alone and significant reduction by ASA of the OOX-induced increase in the bone blood flow. In both groups of OOX females there was a decrease in tibial bone density and ash weight. The changes in 45Ca incorporation were similar to those in the blood flow while the changes in 3H-proline incorporation were not significant. Thus, the effect of ASA, i.e. suppression of the OOX-induced increase in the bone blood flow, is consistent with the possible role of PG (probably PGE2) in the increase in bone blood flow of OOX female rats.