This work was aimed to determine the effect of 17 beta-estradiol (17 beta E) on cell proliferation in human renal tubular epithelial cells (HRTEC) isolated from kidneys from pediatric subjects, as well as the role of estrogen receptors involved in the 17 beta E proliferative response. Treatment with 17 beta E (10 nmol/L, 24h) significantly stimulated cell proliferation, measured by 5-bromo-2-deoxyuridine (BrdU) uptake, in HRTEC primary cultures and in tubular structures obtained by 3D cultured-HRTEC. Incubation of HRTEC with the G protein-coupled estrogen receptor 1 (GPER-1) agonist G-1 increased BrdU uptake. Incubation of HRTEC with 17 beta E activated the classic estrogen receptor alpha (ER alpha) but not ER beta. Treatment of HRTEC with the GPER-1 antagonist G-15, the ER inhibitor ICI182,780, or the beta-catenin inhibitor iCRT14, completely abrogated the increase in BrdU uptake induced by 17 beta E. We also show that 17 beta E stimulated beta-catenin protein expression and translocation to the nucleus of HRTEC, effects that were abrogated by G-15 and ICI 182,780. In conclusion, estradiol stimulates cell proliferation in HRTEC primary cultures through both ER alpha and GPER-1 estrogen receptors and involves beta-catenin activation. (C) 2019 Elsevier Inc. All rights reserved.