title: Regulation of beta 2-adrenergic receptors in keratinocytes: glucocorticoids increase steady-state levels of receptor mRNA in foetal rat keratinizing epidermal cells (FRSK cells).
abstract: Glucocorticoids increase the beta-adrenergic adenylate cyclase response of epidermal keratinocytes. Using FRSK cells, a cultured cell line of foetal rat keratinocytes, the regulatory mechanism of the beta-adrenergic augmentation effect was investigated. Treatment with dexamethasone (1 x 10(-6) M increase by 1.5-fold the beta-adrenergic adenylate cyclase response of FRSK cells. The effect was observed at 6 h incubation and remained for at least 48 h. The prostaglandin E-adenylate cyclase response was also increased 1.5-fold by glucocorticoid treatment. Neither the adenosine-adenylate cyclase response nor cholera toxin- or forskolin-induced cyclic AMP accumulations were altered. Northern blot hybridization showed that levels of the beta 2-adrenergic receptor mRNA increased within 3 h, while actin-, Gs-alpha, Gi-2 alpha, Gi-3 alpha mRNA levels were unchanged. Testosterone, 17 beta-oestradiol, and progesterone had no effect on either the beta 2-adrenergic adenylate cyclase response or the expression of beta 2-adrenergic receptor mRNA. The increase in the numbers of the beta-adrenergic receptors was visualized by immunofluorescence with an antibody specific for the beta 2-adrenergic receptor. Our results indicate that glucocorticoids regulate the beta 2-adrenergic adenylate cyclase response of FRSK cells through the enhanced expression of the receptor.
authors.affiliation: Department of Dermatology, Asuhikawa Medical College, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Iizuka
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D015152:Blotting, Northern; D002460:Cell Line; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000096:biosynthesis; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology*; D004837:Epinephrine / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D015603:Keratinocytes / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
chemical_list: D012333:RNA, Messenger; D011943:Receptors, Adrenergic, beta; D003609:Dactinomycin; D003907:Dexamethasone; D003513:Cycloheximide; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D004837:Epinephrine