title: Expression of 5'-AMP-activated protein kinase with starvation in murine thymocytes.
abstract: The 5'-AMP-activated protein kinase (AMPK) is a key enzyme in the protection of cells during energy crisis. AMPK is a heterotrimer consisting of a catalytic α (α1, 2) subunit and two regulatory subunits, β (β1, 2) and γ (γ1-3). To elucidate the role of AMPK in thymocytes with starvation, we investigated the expression of AMPK in murine thymocytes. The main isoforms expressed were α2, β1, and γ1, of which expression increased time-dependently with starvation, together with an increase in the amount of the active form of AMPK, phospho-AMPKα. In cultured thymocytes, expression of AMPK was induced by dexamethasone, but not by a low glucose concentration in medium. Increased expression was inhibited by glucocorticoid receptor antagonist RU486. Phosphorylation of AMPKα showed an increase with low glucose concentration, but not with dexamethasone. These results suggest that increased expression of AMPK in starved mouse thymocytes is induced by an increase in glucocorticoids and that activation is induced by hypoglycemia.
authors.affiliation: Department of Biochemistry, Tokyo Dental College, Mihama-ku, Chiba, Japan. rkrr_o2002@yahoo.co.jp
authors.forename: Rintarou
authors.initials: R
authors.lastname: Okoshi
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Ohta
authors.forename: Ayako
authors.initials: A
authors.lastname: Ishikawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Sato
authors.forename: Harutoshi
authors.initials: H
authors.lastname: Kizaki
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000096:biosynthesis*; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology; D007003:Hypoglycemia / Q000378:metabolism*; D007527:Isoenzymes / Q000096:biosynthesis; D018655:Lymphocyte Count; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000032:analysis; D013217:Starvation / Q000201:enzymology*; D013950:Thymus Gland / Q000187:drug effects / Q000201:enzymology*
chemical_list: D005938:Glucocorticoids; D007527:Isoenzymes; D012333:RNA, Messenger; D003907:Dexamethasone; D055372:AMP-Activated Protein Kinases