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N-(4-Hydroxyphenyl) retinamide (4HPR) and retinoyl beta-glucuronide (RAG) are two derivatives of all-trans retinoic acid (RA) that show properties both similar to as well as different from their parent compound, RA. Both retinoids possess the important property of showing much-reduced toxicity relative to RA while maintaining significant biological(More)
The intestines of freshly caught Saccobranchus fossilis (a freshwater fish that contains dehydroretinol) became free from carotenoids and from vitamin A when the fish were starved for about 20 days. When beta-carotene was administered to such fish, retinoic acid could be isolated from the intestines after approx. 4h. When lutein was administered to such(More)
A reversed-phase gradient high-performance liquid chromatographic (HPLC) procedure, which utilizes gradient elution and detection by a photodiode-array detector, has been developed to analyze simultaneously very polar retinoids, such as 4-oxo-retinoyl-beta-glucuronide, retinoyl beta-glucuronide and 4-oxo-retinoic acid; polar retinoids, such as retinoic acid(More)
Retinoids are unstable compounds being readily oxidized and/or isomerized to altered compounds, especially in the presence of oxidants including air, light, and excessive heat. They are labile toward strong acids and solvents that have dissolved oxygen or peroxides. In this review, procedures for handling and storage of retinoids and biological samples(More)
BACKGROUND All-trans-retinoyl beta-D-glucuronide, a water-soluble glucuronic acid conjugate of all-trans-retinoic acid, has demonstrated high biological activity and low toxicity in most in vitro and in vivo models. Since the reparative effects of retinoids on epithelium are well-known, our aim was to study the effect(s) of intravenously-administered(More)
Increased intake of fruits and vegetables is associated with reduced risk of cancer and other chronic diseases. Epoxycarotenoids are widely distributed in nature and constitute major dietary carotenoids in a number of fruits and vegetables. Previous studies have shown that beta-carotene 5,6-epoxide was absorbed well by humans, and was much more active than(More)
All-trans-[11-3H]retinoyl beta-glucuronide (RAG) was synthesized in a single step from all-trans-[11-3H]retinoyl fluoride, with a 24% yield. After its intraperitoneal injection into rats, RAG was detected in the blood, liver, intestine and kidney during the following 24 h period. Although the concentration of radiolabelled metabolites decreased with time,(More)
All-trans-[11-3H]retinyl beta-glucuronide (all-trans-[11-3H]ROG) was synthesized from [3H]retinol by an improved synthetic procedure. After its intraperitoneal injection into rats, ROG is initially found as the predominant labelled component in the serum, but then is distributed to the liver, intestine, kidney and other organs of the body. Esters of vitamin(More)