TY - JOUR A1 - Rühl, Ralph A1 - Hamscher, Gerd A1 - Garcia, Ada A1 - Nau, Heinz A1 - Schweigert, Florian J. T1 - Identification of 14-hydroxy-retro-retinol and 4-hydroxy-retinol as endogenous retinoids in rats throughout neonatal development N2 - 14-Hydroxy-retro-retinol was previously described as an in vivo and in vitro metabolite of retinol. Furthermore, the retinoid 4-hydroxy-retinol was identified as an endogenous occurring retinoid in the amphibian organism and an in vitro metabolite of retinol. We describe in the present study that 14-hydroxy-retro-retinol and 4-hydroxy- retinol are present in normal neonatal rat serum as endogenous occurring retinoids in normal non-vitamin A supplemented mammals (rats). Both retinoids were detected in serum and liver of neonatal rats at days 3 and 11 after birth. The respective concentrations at day 11 after birth were 41.8 +/- 2.8 ng/ml (serum)/ 104 +/- 6 ng/g (liver) for 4-hydroxy- retinol and 23 +/- 4.6 ng/ml (serum)/ 285 +/- 5 ng/g (liver) for 14-hydroxy-retro-retinol. Both retinoids could not be detected in adult rat serum and liver. From our experiments important physiological functions of these retinoids during postnatal development could be postulated. (C) 2004 Elsevier Inc. All rights reserved Y1 - 2004 UR - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/15432 SN - 0024-3205 ER -