Biomaterial Database

Altered steroid delta(4)-reductase activity in mammary tumor-bearing rats. 1981

Y J Abul-Hajj

The effect of mammary tumors on steroid delta(4)-reductase activity was investigated using in vitro and in vivo studies in three transplantable rat mammary tumors. Steroid delta(4)-5 alpha-reductase activity was measured spectrophotometrically and was significantly decreased in the host livers from R323OAC and MT/W9a-B but was increased in 7,12-dimethylbenz(a)anthracene-induced No. 14 tumor-bearing rats. There were no significant alterations of 5 beta-reductase activity in all animals investigated. In vivo studies using [14C]testosterone showed a similar pattern for saturation of the 4,5-double bond but that the more than doubled increase in 4,5-reduced metabolites observed in the in vivo studies in 7,12-dimethylbenz(a)anthracene-induced tumor-bearing rats cannot be explained by the increase observed in hepatic enzyme activity. Incubations with mammary tumor tissues showed that 7,12-dimethylbenz(a)anthracene-induced tumors have a very active delta(4)-5 alpha-reductase enzyme which accounts for the observed increases in in vivo results. The surgical removal of the tumor abolishes the impairment in delta(4)-reductase activity.

UI	MeSH Term	Description	Entries
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008325	Mammary Neoplasms, Experimental	Experimentally induced mammary neoplasms in animals to provide a model for studying human BREAST NEOPLASMS.	Experimental Mammary Neoplasms,Neoplasms, Experimental Mammary,Experimental Mammary Neoplasm,Mammary Neoplasm, Experimental,Neoplasm, Experimental Mammary
D009368	Neoplasm Transplantation	Experimental transplantation of neoplasms in laboratory animals for research purposes.	Transplantation, Neoplasm,Neoplasm Transplantations,Transplantations, Neoplasm
D010088	Oxidoreductases	The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)	Dehydrogenases,Oxidases,Oxidoreductase,Reductases,Dehydrogenase,Oxidase,Reductase
D005260	Female		Females
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001646	Bile	An emulsifying agent produced in the LIVER and secreted into the DUODENUM. Its composition includes BILE ACIDS AND SALTS; CHOLESTEROL; and ELECTROLYTES. It aids DIGESTION of fats in the duodenum.	Biliary Sludge,Sludge, Biliary
D013739	Testosterone	A potent androgenic steroid and major product secreted by the LEYDIG CELLS of the TESTIS. Its production is stimulated by LUTEINIZING HORMONE from the PITUITARY GLAND. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to DIHYDROTESTOSTERONE or ESTRADIOL.	17-beta-Hydroxy-4-Androsten-3-one,17-beta-Hydroxy-8 alpha-4-Androsten-3-one,8-Isotestosterone,AndroGel,Androderm,Andropatch,Androtop,Histerone,Sterotate,Sustanon,Testim,Testoderm,Testolin,Testopel,Testosterone Sulfate,17 beta Hydroxy 4 Androsten 3 one,17 beta Hydroxy 8 alpha 4 Androsten 3 one,8 Isotestosterone
D013741	3-Oxo-5-alpha-Steroid 4-Dehydrogenase	An enzyme that catalyzes the reduction of TESTOSTERONE to 5-ALPHA DIHYDROTESTOSTERONE.	3-Keto-5-alpha-Steroid delta-4-Dehydrogenase,5-alpha-Reductase, Testosterone,Testosterone 5-alpha-Reductase,Testosterone delta-4-5-alpha-Reductase,3-oxo-5 alpha-Steroid 4-Dehydrogenase (NADP+),3-oxo-5alpha-Steroid 4-Dehydrogenase (NADP+),4-Ene-3-Oxosteroid-5alpha-Reductase,4-Ene-5-alpha-Reductase,NADH-5-alpha-Reductase,NADPH delta(4)-3-Ketosteroid 5 alpha-Oxidoreductase,Steroid 5-alpha-Reductase,Steroid 5Alpha Reductase,Steroid delta-4-5-alpha Reductase,delta 4-3-keto Steroid 5 alpha-Oxidoreductase,delta(4)-3-Ketosteroid-5alpha-Reductase,delta4-3-ketosteroid 5alpha-Oxidoreductase,3 Keto 5 alpha Steroid delta 4 Dehydrogenase,3 Oxo 5 alpha Steroid 4 Dehydrogenase,4 Ene 3 Oxosteroid 5alpha Reductase,4 Ene 5 alpha Reductase,5 alpha Reductase, Testosterone,5-alpha-Reductase, Steroid,5Alpha Reductase, Steroid,5alpha-Oxidoreductase, delta4-3-ketosteroid,NADH 5 alpha Reductase,Reductase, Steroid 5Alpha,Reductase, Steroid delta-4-5-alpha,Steroid 5 alpha Reductase,Steroid delta 4 5 alpha Reductase,Testosterone 5 alpha Reductase,Testosterone delta 4 5 alpha Reductase,delta 4 3 keto Steroid 5 alpha Oxidoreductase,delta-4-5-alpha Reductase, Steroid,delta-4-5-alpha-Reductase, Testosterone,delta-4-Dehydrogenase, 3-Keto-5-alpha-Steroid,delta4 3 ketosteroid 5alpha Oxidoreductase
D016031	Liver Transplantation	The transference of a part of or an entire liver from one human or animal to another.	Grafting, Liver,Hepatic Transplantation,Liver Transplant,Transplantation, Hepatic,Transplantation, Liver,Hepatic Transplantations,Liver Grafting,Liver Transplantations,Liver Transplants,Transplant, Liver