Vitamin A is normally transported in plasma as retinol bound to a specific protein, retinol-binding protein (RBP). Detailed studies were conducted to examine the effects of excess vitamin A on the plasma concentration and metabolism of RBP, and to obtain information about vitamin A transport in the hypervitaminotic state. Two separate experiments were conducted. In the first (Study I, 99 days),...

Retinyl acetate suppressed the free radical-induced oxidation of methyl linoleate. Retinyl acetate was reacted with an alkylperoxyl radical in two solvent systems, methanol and benzene, The alkylperoxyl radical was generated by the thermal decompositien of a free radical initiator, 2 2'-azobis(2,4-dimethylyaleronitrile), at 370C. The reaction products were isolated by HPLC and their structures ...

Two techniques were used to examine the effect of vitamin A compounds (vitamin A acid = retinoic acid and vitamin A acetate) upon the relative strengths of adhesion among mouse limb-bud mesenchymal cells. Treatment with retinoic acid in vivo and with vitamin A acetate in vitro reduced the rate at which the fragments of mesenchyme rounded-up when cultured on a non-adhesive substratum, but these ...

A study was conducted to explore the effects of retinoic acid, fed to retinol-deficient rats, on the tissue distribution and levels of cellular retinol-binding protein (CRBP) and cellular retinoic acid-binding protein (CRABP). Sensitive and specific radioimmunoassays were employed to measure the levels of both CRBP and CRABP. Two groups of six male rats each were fed a purified retinoid-deficie...

BACKGROUND Model-based compartmental analysis of data on plasma retinol kinetics after administration of labeled retinol provides unique information about whole-body vitamin A metabolism. If labeled β-carotene is coadministered, its bioefficacy relative to the retinol reference dose can also be estimated. OBJECTIVES The objectives were to model plasma retinol kinetics after administration of ...

background: all-trans retinol is a biological antioxidantscavenging the ros in the cell culture. objectives: this studywas conducted to investigate the effect of all-trans retinol infertilization and culture medium on mouse embryo's developmentalcompetence. methods: this study was designed into twoexperiments. in the first experiment, in vitro mature oocytes wereco-cultured with sperm in fertil...

BACKGROUND AND OBJECTIVES Kale is a rich source of provitamin A- β-carotene. This study used intrinsically labeled kale [2H9] β-carotene to determine the effect of peanut butter on the bioconversion of kale β-carotene to vitamin A in preschool children. METHODS AND STUDY DESIGN Preschool children (n=37; age 12-36 mo) were randomly assigned to 50 g cooked kale (1.5 mg β-carotene content) with ...

This study was designed to examine the effects of retinoic acid adding to cumulus and/or fibroblast cellsmonolayer on the development of mouse early embryos. One-cell mouse embryos were obtained from NMRImice after superovulation by an intraperitoneal injection of 5 IU equine chorionic gonadotrophin (eCG)followed 48 hrs later by 5 IU human chorionic gonadotrophin (hCG). Mouse embryonic fibrobla...

We have previously shown that membranes from the retinal pigment epithelium can transform added all-trans-retinol into a mixture of 11-cis-retinoids, demonstrating the "missing reaction" in the visual cycle for the first time (Bernstein, P. S., Law, W. C., and Rando, R. R. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 1849-1853). In this article, this isomerase activity is further characterized. Dou...

I . The mean liver retinol reserve (retinal+ retinyl esters, expressed as retinol) of six newborn lambs was 21 ? 8 pg. The mean value for ten suckled lambs, aged 5-7 days, was 2655 +47z pg retinol per liver. 2. Three unsuckled lambs were fed ad lib. from birth for 28 days on a high-protein diet, based on lard and skim milk, without supplementary vitamin A. The diet provided sufficient vitamin A...