Biomaterial Database

Retinoic acid isomers applied to human skin in vivo each induce a 4-hydroxylase that inactivates only trans retinoic acid. 1996

E A Duell, and S Kang, and J J Voorhees

Department of Dermatology, University of Michigan Medical School, Ann Arbor 48109-0528, USA.

Application of all-trans retinoic acid to human skin for 4 d under occlusion produces a marked increase in retinoic acid 4-hydroxylase activity. In this study, the possible induction of other hydroxylase in response to 9-cis and 13-cis retinoic acid application to adult human skin in vivo was determined. Application of 0.1% all-trans, 0.1% 9-cis, and 0.1% 13-cis retinoic acid to human skin for 2 d resulted in induction of only all-trans retinoic acid 4-hydroxylase activity. The 4-hydroxylase activity in microsomes from the treated tissue ranged from 838 +/- 46 to 531 +/- 59 pg of 4- hydroxy all-trans retinoic acid formed/min/mg protein (n=6). These same preparations were unable to use 9-cis or 13-cis retinoic acid as substrate for the hydroxylation reaction. Extraction of the retinoic acid isomers from epidermis 48 h after application of 0.1% solution of each isomer yielded significant amounts of all-trans retinoic acid (36-72%) regardless of the isomer applied. The all-trans isomer produced by isomerization of both 9-cis and 13-cis retinoic acids is the likely inducer of the 4-hydroxylase. All-trans retinol and all-trans retinal were unable to compete with all-trans retinoic acid as substrate for 4-hydroxylase enzyme. The 4-hydroxylase induced in response to pharmacological doses of retinoic acids is specific for the all-trans isomer. The inability of 9-cis or 13-cis retinoic acid to induce their own hydroxylation and inactivation or act as substrate for the 4-hydroxylase in skin may have considerable implications in light of the clinical use of retinoids in the treatment of various diseases including cancers.

UI	MeSH Term	Description	Entries
D007536	Isomerism	The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Isomerisms
D008861	Microsomes	Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	Microsome
D003577	Cytochrome P-450 Enzyme System	A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.	Cytochrome P-450,Cytochrome P-450 Enzyme,Cytochrome P-450-Dependent Monooxygenase,P-450 Enzyme,P450 Enzyme,CYP450 Family,CYP450 Superfamily,Cytochrome P-450 Enzymes,Cytochrome P-450 Families,Cytochrome P-450 Monooxygenase,Cytochrome P-450 Oxygenase,Cytochrome P-450 Superfamily,Cytochrome P450,Cytochrome P450 Superfamily,Cytochrome p450 Families,P-450 Enzymes,P450 Enzymes,Cytochrome P 450,Cytochrome P 450 Dependent Monooxygenase,Cytochrome P 450 Enzyme,Cytochrome P 450 Enzyme System,Cytochrome P 450 Enzymes,Cytochrome P 450 Families,Cytochrome P 450 Monooxygenase,Cytochrome P 450 Oxygenase,Cytochrome P 450 Superfamily,Enzyme, Cytochrome P-450,Enzyme, P-450,Enzyme, P450,Enzymes, Cytochrome P-450,Enzymes, P-450,Enzymes, P450,Monooxygenase, Cytochrome P-450,Monooxygenase, Cytochrome P-450-Dependent,P 450 Enzyme,P 450 Enzymes,P-450 Enzyme, Cytochrome,P-450 Enzymes, Cytochrome,Superfamily, CYP450,Superfamily, Cytochrome P-450,Superfamily, Cytochrome P450
D004790	Enzyme Induction	An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.	Induction, Enzyme
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000072516	Retinoic Acid 4-Hydroxylase	A cytochrome P450 enzyme that resides in the ENDOPLASMIC RETICULUM. It catalyzes the conversion of trans-RETINOIC ACID to 4-hydroxyretinoic acid.	CYP26A1,CYP26A1 Enzyme,CYP26B1,CYP450 4-Hydroxylase,Cytochrome P-450 26B1,Cytochrome P-450 CYP26B1,Cytochrome P450 26A1 Enzyme,Cytochrome P450 4-Hydroxylase,P450RAI,RA-4-Hydroxylase,Retinoic Acid-Metabolizing Enzyme, CYP26B1,CYP26B1, Cytochrome P-450,Cytochrome P 450 CYP26B1,Cytochrome P450 4 Hydroxylase,Enzyme, CYP26A1,RA 4 Hydroxylase,Retinoic Acid 4 Hydroxylase,Retinoic Acid Metabolizing Enzyme, CYP26B1
D000287	Administration, Topical	The application of drug preparations to the surfaces of the body, especially the skin (ADMINISTRATION, CUTANEOUS) or mucous membranes. This method of treatment is used to avoid systemic side effects when high doses are required at a localized area or as an alternative systemic administration route, to avoid hepatic processing for example.	Drug Administration, Topical,Administration, Topical Drug,Topical Administration,Topical Drug Administration,Administrations, Topical,Administrations, Topical Drug,Drug Administrations, Topical,Topical Administrations,Topical Drug Administrations
D012867	Skin	The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D014212	Tretinoin	An important regulator of GENE EXPRESSION during growth and development, and in NEOPLASMS. Tretinoin, also known as retinoic acid and derived from maternal VITAMIN A, is essential for normal GROWTH; and EMBRYONIC DEVELOPMENT. An excess of tretinoin can be teratogenic. It is used in the treatment of PSORIASIS; ACNE VULGARIS; and several other SKIN DISEASES. It has also been approved for use in promyelocytic leukemia (LEUKEMIA, PROMYELOCYTIC, ACUTE).	Retinoic Acid,Vitamin A Acid,Retin-A,Tretinoin Potassium Salt,Tretinoin Sodium Salt,Tretinoin Zinc Salt,Vesanoid,all-trans-Retinoic Acid,beta-all-trans-Retinoic Acid,trans-Retinoic Acid,Acid, Retinoic,Acid, Vitamin A,Acid, all-trans-Retinoic,Acid, beta-all-trans-Retinoic,Acid, trans-Retinoic,Potassium Salt, Tretinoin,Retin A,Salt, Tretinoin Potassium,Salt, Tretinoin Sodium,Salt, Tretinoin Zinc,Sodium Salt, Tretinoin,Zinc Salt, Tretinoin,all trans Retinoic Acid,beta all trans Retinoic Acid,trans Retinoic Acid