Effect of the 17beta-aminoestrogen pentolame on bone mineral levels in ovariectomized rats.

Estrogens are fundamental to maintaining bone mineral balance. 17beta-aminoestrogens produce low estrogenic effects through ERalpha and ERbeta receptors, however their effects on bone tissue are unknown. This work evaluates the effects of the 17beta-aminoestrogen pentolame (AEP) and estradiol (E2) on the mineral profile of rat femur. Six months after ovariectomy (Ovx) adult Wistar rats (200-250g) were treated every third day for 30 days with subcutaneous (s.c.) injections of E2 (1, 10, 100 microg/kg), AEP (1, 10, 100, 500 microg/kg) or vehicle (propylenglycol; 1 ml/kg). After treatment, femur samples were prepared and Ca, P, Mg, Si, Fe, S, Na, K, and Cl concentration profiles were estimated using an X-ray analysis system coupled to an scanning electron microscope. Ovariectomy significantly decreased Ca, P, Mg and Si and increased Fe and S. Treatment with E2 restored Ca, P, Mg, and Si to the control values and decreased Fe and S in a dose dependent manner. AEP restored the levels of Ca, P, Mg and Si at all doses administered. AEP increased the levels of Fe and restored S to the basal level. The other minerals showed great variability and no significant differences were detected. Our results indicate differential action of AEP related to E2 in the restitution of bone mineral content.