Effects of alendronate treatment on serum levels of osteoprotegerin and total receptor activator of nuclear factor κB in women with postmenopausal osteoporosis

We conclude that the determination of total RANKL integrates the free RANKL and the fraction bound to OPG. The apparent decrease in the serum levels of OPG might reflect an increase in OPG binding to RANKL, which results in a beneficial effect on bone.