RANKL/OPG system regulation by endogenous PTH and PTH1R/ATF4 axis in bone: Implications for bone accrual and strength in growing rats with mild uremia.

•An experimental model of mild, chronic kidney disease (CKD) in growing rats was used.•Bone RANKL, RANKL/OPG ratios decreased during 3-month CKD development.•Serum PTH, bone PTH1R/ATF4 axis, cortical bone accrual and strength rise at this time.•Decrease in RANKL/OPG system depends on PTH-mediated activation of PTH1R/ATF4 pathway.•Endogenous PTH exerts beneficial effect oncortical bone accrual and strength.