Dexamethasone rapidly increases calcium channel subunit messenger rna expression and high voltage-activated calcium current in clonal pituitary cells

• Published in: Neuroscience Vol. 72; no. 3; pp. 857 - 862
• Main Authors: Fomina, A.F., Levitan, E.S., Takimoto, K.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.1996; Elsevier
• Subjects: Animals; Biological and medical sciences; calcium channel subunits; Calcium Channels - drug effects; Calcium Channels - physiology; calcium currents; Dexamethasone - pharmacology; Fundamental and applied biological sciences. Psychology; Gene Expression - drug effects; General aspects. Hormone interactions. Hormone actions on several organ systems. Adaptive reactions; glucocorticoids; Pituitary Gland - drug effects; Pituitary Gland - physiology; RNA, Messenger - metabolism; Vertebrates: endocrinology; GH; HVA; calcium currents; HEPES; LVA; calcium channel subunits; glucocorticoids; EGTA; Corticosteroid; Endocrine gland; Dexamethasone; Calcium; Rat; Rodentia; Ionic channel; Gene expression; Subunit; Vertebrata; Mammalia; Cell line; Adrenal hormone; Pituitary gland
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/0306-4522(95)00580-3

Glucocorticoid hormones increase voltage-gated Ca 2+ current density in clonal pituitary cells. To test whether these steroids might stimulate expression of Ca 2+ channel genes, messenger RNase protection assays were used to measure α 1C and α 1D RNAs that encode pore-forming subunits of l-type Ca 2+ channels. We show here that dexamethasone rapidly increases α 1C messenger RNA expression without affecting α 1D messenger RNA level. This up-regulation of channel messenger RNA is also produced by natural glucocorticoids and is blocked by the glucocorticoid antagonist Ru48386. The up-regulation of the channel subunit messenger RNA expression is associated with an increase in high voltage-activated Call current density. Thus, glucocorticoids may produce a long-term effect on Ca 2+ homeostasis in clonal pituitary cells by differentially regulating expression of Ca 2+ channel subunit genes.