Retinoid metabolism in spontaneously transformed mouse fibroblasts (Balb/c 3T12-3 cells): enzymatic conversion of retinol to anhydroretinol

Spontaneously transformed mouse fibroblasts (Balblc 3T 12-3 cells) displayed an increased adhesion when cultured in the presence of loF6 M all-trans retinol and acquired morphological characteristics of the normal phenotype. Thus it was of interest to investigate the metabolism of [ 15-14C]retinol in this system. Within 24 hours of culture, approximately 4.25% of the [14C]retinol was taken up by the cells. The hydrocarbon [14C]anhydroretinol was a major metabolic product and was identified by gas-liquid chromatography and by its typical ultraviolet absorption spectrum with maxima at 386, 364, and 346 nm. At 24 and 40 hours anhydroretinol represented 27% and 55%, respectively, of the total nonpolar metabolites or approximately 16% and 30% of the total radioactive products. Formalin-fixed fibroblasts or cultured intestinal mucosal cells did not convert retinol into anhydroretinol. A more polar product with a UV absorption maximum at 310 nm was also found. The time course of the synthesis of this product by 3T12 cells suggested a precursor-product relationship with anhydroretinol. A microsomal preparation from 3T 12 cells was also active in synthesizing [14C]anhydroretinol and [14C]metabolite- 3 10 from [14C]retinol. Moreover incubation of metabolite-3 10 with the 3T12 microsomes yielded anhydroretinol(40% conversion in 30 minutes), suggesting that metabolite-310 is an intermediate in the synthesis of anhydroretinol by these cells. Anhydroretinol appears to be an end product of the metabolism of retinol in 3T12-3 cells, as suggested by the finding that over 90% of [14C]anhydroretinoli ncubated for 30 hours with 3T12-3 cells was recovered unaltered, without the formation of detectable retroretinol, retinol, or retinoic acid.- Bhat, P. V., L. M. De Luca, S. Adamo, I. Akalovsky, C. S. Silverman-Jones, and G. L. Peck. Retinoid metabolism in spontaneously transformed mouse fibroblasts (Balbk 3T12-3 cells): enzymatic conversion of retinol to anhydroretinol. J . Lipid Re\. 1979. 20: 357-362.