ALIN CONSTANTIN PINZARIU, TEODOR OBOROCEANU, FLORIN ZUGUN ELOAE, IOANA HRISTOV, VICTOR VLAD COSTAN, LUMINITA LABUSCA, PETRU CIANGA, LILIANA VERESTIUC, BIANCA HANGANU, DRAGOS VALENTIN CRAUCIUC,IRINA SMARANDA MANOILESCU, EUSEBIU VIOREL SINDILAR, VERONICA MOCANU VITAMIN D AS A REGULATOR OF ADIPOCYTE DIFFERENTIATION EFFECTS IN VIVO AND IN VITRO The age-associated adiposity and the effect of long-term vitamin D was studied in vitamin D deficient rats. In in vivo experiments, the influence of a 9 months of vitamin D treatment (weekly oral gavage with 0.125 mg vitamin D3 (5000 IU)/100g body weight) on the adipocyte precursors from the omental adipose tissue was examinated. In in vitro experiment, rat adipose-derived mesenchymal stromal/stem cells (ASCs) were induced to differentiate into adipocytes in the presence or absence of 25(OH)D3 (0.25, 25, and 2500 nmol/L). ASCs derived from vitamin D-treated animals showed an increase adipogenic potential as compared to vitamin D-deficient rats. The addition of 25(OH)D3 inhibits the adipocyte differentiation and lipid deposition in a dose dependent manner.