title: The role of calcium channels in hamster CYP11B2 gene expression.
abstract: Previous studies have shown that the hamster CYP11B2 gene promoter is under the influence of angiotensin II (AII), cAMP and potassium (K+). However, very little is known about the mechanisms by which these compounds regulate the transcription of the CYP11B2 gene. Therefore we analysed the 5'-flanking region of the hamster CYP11B2 gene using a transient transfection expression system in NCI-H295 adrenocortical cells, which are known to respond to K+, cAMP and AII. The first 486 bp before the transcription initiation site were introduced upstream of the chloramphenicol acetyl transferase gene. NCI-H295 cells transfected with this -486 construct showed increased CAT activity upon treatment by K+, AII, forskolin and cAMP. The calcium channel antagonist nifedipine partially blocked the enhancing effects of AII, forskolin and cAMP by 35%, 30% and 30% respectively, whereas it completely blocked the stimulatory effects of KCl (1). These results thus show the involvement of calcium channels in the regulation of CYP11B2 gene transcription by K+, and their partial involvement in the regulation of this gene by AII, forskolin and cAMP in NCI-H295 cells.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, University of Sherbrooke, QC, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Sarazin
authors.forename: A
authors.initials: A
authors.lastname: Lefebvre
authors.forename: J G
authors.initials: JG
authors.lastname: LeHoux
mesh_terms: D000302:Adrenal Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology*; D002460:Cell Line; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D005576:Colforsin / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006224:Cricetinae / Q000235:genetics*; D000242:Cyclic AMP / Q000494:pharmacology; D019405:Cytochrome P-450 CYP11B2 / Q000235:genetics*; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D009543:Nifedipine / Q000494:pharmacology; D011189:Potassium Chloride / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014162:Transfection
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D000804:Angiotensin II; D005576:Colforsin; D011189:Potassium Chloride; D000242:Cyclic AMP; D019405:Cytochrome P-450 CYP11B2; D002795:Choline O-Acetyltransferase; D009543:Nifedipine