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Journal of Mass Spectrometry : JMS Aug 2001Since retinoic acid (RA) and RA receptors are key developmental regulators during organogenesis, they might participate in the abnormal development of the prostate...
Since retinoic acid (RA) and RA receptors are key developmental regulators during organogenesis, they might participate in the abnormal development of the prostate caused by early estrogen exposure. In order to test this assumption, a sensitive analytical method that can differentiate 9-cis, 13-cis, and all-trans RA in small tissue samples ( approximately 8 mg) is required. Since retinol is the metabolic precursor to RA, simultaneous quantification of retinol would also provide valuable information. Here, we report a liquid chromatography-mass spectrometry method for simultaneous determination of retinol and 9-cis, 13-cis, and all-trans RA in rat prostate. Mass spectrometric signal responses for RA were compared using positive ion atmospheric-pressure chemical ionization (APCI) and electrospray, as well as positive ion and negative ion APCI. Positive ion APCI was selected for all subsequent analysis for its better sensitivity, and to provide simultaneous determination of retinol and RA. Ventral prostate tissue samples were homogenized and extracted following simple protein precipitation without derivatization. Baseline separation of 9-cis, 13-cis, and all-trans RA standards was obtained by using a non-porous silica C18 column. Selected ion monitoring of the ions m/z 301 and m/z 269 was carried out for mass spectrometric quantitative analysis. The ion of m/z 301 corresponded to the protonated molecule of RA, whereas the ion of m/z 269 corresponded to loss of water or acetic acid from the protonated molecule of retinol or the internal standard retinyl acetate respectively. The method has a linear response over a concentration range of at least three orders of magnitude. The limit of quantitation was determined to be 702 fmol all-trans RA injected on-column. The method showed excellent intra- and inter-assay reproducibility and good recovery, and is suitable for analyzing RA and retinol in small tissue samples (approximately 8 mg).
Topics: Alitretinoin; Animals; Chromatography, Liquid; Isotretinoin; Male; Mass Spectrometry; Prostate; Rats; Tretinoin; Vitamin A
PubMed: 11523087
DOI: 10.1002/jms.189 -
The Journal of Investigative Dermatology Jan 1996The potential for all-trans-retinoic acid to regulate the metabolism of 3H-retinol and 3H-3,4-didehydroretinol was examined in cultured human epidermal keratinocytes....
The potential for all-trans-retinoic acid to regulate the metabolism of 3H-retinol and 3H-3,4-didehydroretinol was examined in cultured human epidermal keratinocytes. Confluent cultures were treated daily with medium containing 5% fetal bovine serum or the same medium supplemented with nanomolar concentrations of all-trans-retinoic acid for up to 3 d. During the last 24 of treatment, cells were incubated with 3H-retinol or 3H-3,4-didehydroretinol for 24 h (isotopic steady state) to label the endogenous retinoids. After the labeling period, one group of cells was harvested and another group was allowed to incubate for an additional 24 h in the absence of medium retinol for the determination of endogenous 3H-retinoid utilization. The 3H-retinoids present in cells were extracted and quantitated by reverse-phased high-pressure liquid chromatography. Keratinocytes treated with retinoic acid and labeled with 3H-retinol exhibited time- and concentration-dependent (i) increases in retinyl ester mass, (ii) increases in the rate of retinyl ester synthesis, (iii) decreases in retinyl ester utilization, and (iv) decreases in the cellular concentrations of retinoic and 3,4-didehydroretinoic acids. There was no effect of exogenous retinoic acid on its own metabolism. Cells labeled with 3H-3,4-didehydroretinol exhibited exclusive labeling of vitamin A2-related retinoids suggesting that the A1 to A2 conversion is not reversible. Treatment of cells with low nanomolar concentrations of retinoic acid decreased the utilization of 3,4-didehydroretinyl esters, decreased the production of 3,4-didehydroretinoic acid but had no effect on the synthesis of 3,4-didehydroretinol or its esters. The results demonstrate that keratinocytes respond to extracellular retinoic acid by decreasing endogenous production of active retinoids, sequestering extracellular substrate retinol as retinyl ester, and decreasing ester utilization.
Topics: Adult; Cells, Cultured; Epidermal Cells; Epidermis; Humans; Keratinocytes; Male; Retinoids; Tretinoin; Vitamin A
PubMed: 8592069
DOI: 10.1111/1523-1747.ep12329900 -
Archives of Biochemistry and Biophysics Sep 2001Because only retinol and not all-trans-retinoic acid (atRA) can satisfy all of the functions of vitamin A, we have investigated the retinol metabolites in tissues of...
Because only retinol and not all-trans-retinoic acid (atRA) can satisfy all of the functions of vitamin A, we have investigated the retinol metabolites in tissues of vitamin A-deficient (VAD) rats responding to a radioactive dose of [20-(3)H]all-trans-retinol. As expected, atRA is the major vitamin A metabolite present in the target tissues of VAD rats given a physiological dose (1 microg) of [20-(3)H]all-trans-retinol (atROL). Both atROL and atRA were detected by high-performance liquid chromatographic (HPLC) analysis of the radioactivity extracted from the liver, kidney, small intestine, lung, spleen, bone, skin, or testis of these animals. Novel retinol metabolites were observed in the aqueous extracts from the testis, lung, and skin. However, these metabolites were detected in very small amounts and were not characterized further. Importantly, neither 9-cis-retinoic acid (9cRA), 9-cis-retinol (9cROL), nor 13-cis-retinoic acid (13cRA) was present in detectable amounts. The amounts of atRA varied in each tissue, ranging from 0.29 +/- 0.05 fmol of RA/g of tissue in the femurs to 12.9 +/- 4.3 fmol of RA/g of tissue in the kidneys. The absence of 9cRA in vivo was not due to degradation of this retinoid during the extraction procedure or HPLC analysis of the extracted radioactivity. As atROL completely fulfills all of the physiological roles of vitamin A, and 9cRA is not detected in any of the tissues analyzed, these results suggest that 9cRA may have no physiological relevance in the rat.
Topics: Alitretinoin; Animals; Chromatography, High Pressure Liquid; Lung; Male; Protein Isoforms; Rats; Rats, Sprague-Dawley; Retinoids; Testis; Tissue Distribution; Tretinoin; Vitamin A; Vitamin A Deficiency
PubMed: 11556813
DOI: 10.1006/abbi.2001.2495 -
Journal of Ocular Pharmacology and... Jun 2010To determine whether a nonprotein lipophilic carrier, 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD), can remove all-trans retinol from rod photoreceptor outer segments....
PURPOSE
To determine whether a nonprotein lipophilic carrier, 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD), can remove all-trans retinol from rod photoreceptor outer segments. All-trans retinol is generated in rod outer segments after light exposure. It is highly insoluble, and its efficient transport across extra- and intracellular aqueous space requires specialized carriers.
METHODS
Experiments were carried out with isolated frog rod photoreceptor cells. The removal of all-trans retinol by different concentrations of this carrier was measured by imaging its fluorescence in single-rod photoreceptors.
RESULTS
HP-beta-CD concentrations >0.3 mM significantly increased the rate of all-trans retinol removal. The rate of removal increased linearly with carrier concentration, with a slope of 0.0058 min(-1)/mM.
CONCLUSIONS
The effectiveness of HP-beta-CD shows that a specialized interaction with the cell membrane is not necessary for the efficient transfer of all-trans retinol between the cell membrane and the carrier. The transfer occurs through a collision-based mechanism, as indicated by the linear increase of the rate of removal with the carrier concentration.
Topics: 2-Hydroxypropyl-beta-cyclodextrin; Animals; Cell Membrane; Dose-Response Relationship, Drug; Drug Carriers; Fluorescence; In Vitro Techniques; Rana pipiens; Rod Cell Outer Segment; Vitamin A; beta-Cyclodextrins
PubMed: 20565310
DOI: 10.1089/jop.2010.0020 -
Nutrients Oct 2022All-trans-retinoic acid (RA), a metabolite of vitamin A (retinol), exerts profuse actions that enable multiple aspects of reproduction, embryonic development and...
All-trans-retinoic acid (RA), a metabolite of vitamin A (retinol), exerts profuse actions that enable multiple aspects of reproduction, embryonic development and post-natal regulation of energy metabolism, glucoregulatory control, organ function, and of the skeletal, immune, nervous and cardiovascular systems, as well as cell proliferation vs [...].
Topics: Pregnancy; Female; Humans; Tretinoin; Vitamin A; Autacoids
PubMed: 36364786
DOI: 10.3390/nu14214526 -
Pharmaceutical Research Jul 2009The aim of this research is to investigate the dermal delivery of all-trans-retinol from nanoparticle-coated submicron oil-in-water emulsions as a function of the...
PURPOSE
The aim of this research is to investigate the dermal delivery of all-trans-retinol from nanoparticle-coated submicron oil-in-water emulsions as a function of the initial emulsifier type, the loading phase of nanoparticles, and the interfacial structure of nanoparticle layers.
METHODS
The interfacial structure of emulsions was characterized using freeze-fracture-SEM. In-vitro release and skin penetration of all-trans-retinol were studied using Franz diffusion cells with cellulose acetate membrane, and excised porcine skin. The distribution profile was obtained by horizontal sectioning of the skin using microtome-cryostat and HPLC assay.
RESULTS
The steady-state flux of all-trans-retinol from silica-coated lecithin emulsions was decreased (up to 90%) and was highly dependent on the initial loading phase of nanoparticles; incorporation from the aqueous phase provided more pronounced sustained release. For oleylamine emulsions, sustained release effect was not affected by initial location of nanoparticles. The skin retention significantly (p < or = 0.05) increased and was higher for positive oleylamine-stabilised droplets. All-trans-retinol was mainly localized in the epidermis with deeper distribution to viable skin layers in the presence of nanoparticles, yet negligible permeation (approximately 1% of topically applied dose) through full-thickness skin.
CONCLUSIONS
Sustained release and targeted dermal delivery of all-trans-retinol from oil-in-water emulsions by inclusion of silica nanoparticles is demonstrated.
Topics: Administration, Cutaneous; Animals; Drug Delivery Systems; Emulsions; Nanoparticles; Silicon Dioxide; Skin Absorption; Swine; Vitamin A
PubMed: 19384464
DOI: 10.1007/s11095-009-9888-0 -
International Journal For Vitamin and... Sep 2007We established a reference range for dl-alpha-tocopherol and all-trans-retinol in a Saudi population previously selected for a cross-sectional study evaluating selenium...
We established a reference range for dl-alpha-tocopherol and all-trans-retinol in a Saudi population previously selected for a cross-sectional study evaluating selenium and vitamin status. Concentrations of dl-alpha-tocopherol and all-trans-retinol were 0.999 +/- 0.31 mg/dL (n=994, range 0.11-3.42 mg/dL) and 49.14 +/- 24.15 micro/dL (n=1000, range 11.20-400.85 microg/dL), respectively. The levels of dl-alpha-tocopherol and all-trans-retinol in serum were determined by high-pressure liquid chromatography (HPLC) equipped with a UV detector. We took the influence of age and gender into account. Both had significant effect on the levels of all-trans-retinol in serum, except in the case of dl-alpha-tocopherol, where no gender related effect was found. We used the 5th and 95th percentiles as reference limits. Based on these criteria, it was found that these reference limits differed between genders for all-trans-retinol. Our lower and upper limits for dl-alpha-tocopherol classified by three age groups were very close to the normal range of 0.5-1.6 mg/dL, as found in previous studies. The 5th percentile of all-trans-retinol in both males and females, stratified by age, was close to a level of <20 microg/dL, which could be regarded as a mild vitamin A deficiency according to WHO criteria. But the value corresponding to the 95th percentile was higher than the upper limit of vitamin A's normal range of 70 microg/dL, suggesting a potentially harmful high dietary intake of vitamin A. The reference intervals elaborated here may help in the assessment of the vitamin status and in detecting subjects at risk of developing pathologies associated with either excess intake or deficiency.
Topics: Adolescent; Adult; Age Factors; Aged; Child; Chromatography, High Pressure Liquid; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Reference Values; Saudi Arabia; Sex Factors; Vitamin A; alpha-Tocopherol
PubMed: 18453317
DOI: 10.1024/0300-9831.77.5.326 -
Science (New York, N.Y.) Jun 1987Thirty years have elapsed since Wald and his colleagues showed that 11-cis retinal was isomerized to all-trans when rhodopsin was bleached, yet little has been...
Thirty years have elapsed since Wald and his colleagues showed that 11-cis retinal was isomerized to all-trans when rhodopsin was bleached, yet little has been understood about the reverse process that generates 11-cis retinal for rhodopsin regeneration. It is not known whether the isomerization is enzyme-mediated, whether it occurs in the pigment epithelium or in the retina, or whether retinal, retinol, or a retinyl ester is the vitamin A compound that is isomerized. Radiolabeled all-trans retinol and high-performance liquid chromatography have now been used to demonstrate the existence of an eye-specific, membrane-bound enzyme (retinol isomerase) that converts all-trans to 11-cis retinol in the dark. Retinol isomerase is concentrated in the pigment epithelium; this localization clarifies the role of this tissue in rhodopsin regeneration and explains the need to transfer all-trans retinol from the rod outer segments to the pigment epithelium during the visual cycle.
Topics: Animals; Anura; Choroid; Chromatography, High Pressure Liquid; Dark Adaptation; Hot Temperature; In Vitro Techniques; Isomerases; Light; Liver; Phenylmethylsulfonyl Fluoride; Pigment Epithelium of Eye; Rats; Retina; Trypsin; Vitamin A; cis-trans-Isomerases
PubMed: 3603006
DOI: 10.1126/science.3603006 -
Toxicology and Applied Pharmacology Jul 1995Large doses of retinol (vitamin A) have been shown to potentiate the hepatotoxicity of several chemicals in rats. The objective of this study was to determine how...
Large doses of retinol (vitamin A) have been shown to potentiate the hepatotoxicity of several chemicals in rats. The objective of this study was to determine how retinol would affect the pulmonary and hepatic toxicity caused by 1-nitronaphthalene (1-NN). All-trans-retinol (75 mg/kg/day, po) was administered for 7 days to male Sprague-Dawley rats. One day after the last dose of retinol, animals were given a single injection of 1-NN (100 mg/kg, ip). At 24 hr, animals receiving retinol vehicle and 1-NN exhibited respiratory distress syndrome and chromodacryorrhea. Pulmonary morphological changes included necrosis and exfoliation of the bronchiolar epithelium, as well as infiltration of inflammatory cells into the interstitial areas around affected bronchioles. The bronchioalveolar lavage fluid from these animals exhibited significant increases in the activities of gamma-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH), as well as protein and inflammatory cell content. Following pretreatment with retinol, none of the animals treated with 1-NN exhibited outward signs of toxicity. In addition, the lavage fluid of these rats revealed significant reductions in inflammatory cells, protein, and LDH activity. However, lavage fluid GGT activity was significantly increased. Morphological evaluation of the lungs revealed nonciliated bronchiolar epithelial (Clara) cell damage with no associated inflammation. Retinol pretreatment resulted in potentiated hepatotoxicity as indicated by increases in plasma alanine aminotransferase and GGT activities, as well as plasma total bilirubin. The altered plasma enzyme activities correlated with increased hepatocyte and bile duct epithelial necrosis, as well as an increased infiltration of neutrophils into the areas around bile ducts. Retinol potentiation of 1-NN-induced hepatocyte necrosis was significantly reduced following pretreatment with gadolinium chloride (GdCl3). From these experiments, we conclude that in the lung pretreatment with retinol decreased the severity of 1-NN-induced toxicity apparently by an anti-inflammatory mechanism. In the liver, retinol potentiated 1-NN-induced liver injury apparently through a proinflammatory mechanism by activating Kupffer cells and increasing the infiltration of neutrophils into the periportal regions adjacent to bile ducts.
Topics: Animals; Anti-Inflammatory Agents; Eating; Liver; Lung; Male; Naphthalenes; Rats; Rats, Sprague-Dawley; Vitamin A; gamma-Glutamyltransferase
PubMed: 7597703
DOI: 10.1006/taap.1995.1135 -
Drug Metabolism and Disposition: the... Mar 2000Oxidative conversion of all-trans-retinol (t-ROH) to all-trans-retinal (t-RAL) is recognized as the rate-limiting step for biosynthesis of all-trans-retinoic acid from...
Oxidative conversion of all-trans-retinol (t-ROH) to all-trans-retinal (t-RAL) is recognized as the rate-limiting step for biosynthesis of all-trans-retinoic acid from t-ROH in mammalian hepatic tissues. The purpose of this study was to investigate the role of human cytochrome P-450 (CYP)-dependent monooxygenation in the conversion of t-ROH to t-RAL. Adult human liver microsomes (HLMS) were incubated with t-ROH, and retinoids generated were identified and quantified by liquid chromatography-mass spectroscopy, HPLC, and other methods. HLMS-catalyzed generation of t-RAL from t-ROH was primarily NADPH-dependent and was strongly inhibited by carbon monoxide. Rates of reactions increased linearly with time and concentrations of HLMS, and exhibited classical substrate saturation. These observations strongly indicated that the reaction proceeded via CYP-catalyzed monooxygenation. On the basis of responses to selective chemical inhibitors, isoforms from CYP family 1 and the CYP3A subfamily appeared to be very active. Members of the CYP2C subfamily and CYP2D6 exhibited lesser activities and CYP2A6, CYP2B6, and CYP2E1 were virtually inactive. cDNA-expressed human CYP enzymes (CYP SUPERSOMES) also were used to assess the capacity of individual CYP enzymes to catalyze the reaction. Based on responses to selective chemical inhibitors, specific activities, and levels present in adult human hepatic tissues, CYP1A2 and CYP3A4 strongly appeared to be the major CYP enzymes catalyzing hepatic oxidative conversion of t-ROH to t-RAL in the adult human liver. CYP1A1 and CYP1B1 SUPERSOMES both exhibited exceptionally high activities, and in extrahepatic tissues, these isoforms could play important roles in biosynthesis of all-trans-retinoic acid from t-ROH.
Topics: Adult; Animals; Catalysis; Chromatography, High Pressure Liquid; Chromatography, Liquid; Cytochrome P-450 Enzyme System; Cytochromes b5; Humans; Isoenzymes; Kinetics; Mass Spectrometry; Microsomes; Microsomes, Liver; NADP; NADPH-Ferrihemoprotein Reductase; Oxidation-Reduction; Tretinoin; Vitamin A
PubMed: 10681376
DOI: No ID Found