title: Growth hormone regulation of the cytochrome P-450IIC subfamily in the rat: inductive, repressive, and transcriptional effects on P-450f (IIC7) and P-450PB1 (IIC6) gene expression.
abstract: The effects of growth hormone (GH) on two constitutively expressed rat liver cytochrome P-450 (P-450) enzymes, namely P-450f (IIC7) and P-450PB1 (IIC6), have been investigated. Hypophysectomy of both male and female rats results in low expression of P-450f. Single daily injections of GH cannot restore expression of P-450f but further repress it. Continuous administration of GH, on the other hand, increases expression of P-450f to levels comparable to those of the normal male and female rat. P-450PB1 is minimally affected by hypophysectomy or GH treatment, although a weak but significant repression by continuous administration of GH can be detected. Run-on analysis shows that continuous GH treatment increases transcription of P-450f. In addition, the sequence of the 5' flanking region of this gene reveals DNA segments that might have a putative role in the transcriptional regulation of P-450f by GH.
authors.affiliation: Department of Medical Nutrition, Huddinge University Hospital, Karolinska Institute, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Westin
authors.forename: A
authors.initials: A
authors.lastname: Ström
authors.forename: J A
authors.initials: JA
authors.lastname: Gustafsson
authors.forename: P G
authors.initials: PG
authors.lastname: Zaphiropoulos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects / Q000235:genetics; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D013006:Growth Hormone / Q000494:pharmacology*; D007016:Hypophysectomy; D008099:Liver / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D012333:RNA, Messenger; D013006:Growth Hormone; D003577:Cytochrome P-450 Enzyme System