Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Effect of phorbol esters on mitochondrial actions of glucagon

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:6065805
; ;

Glucagon generates different second messenger signals in liver. It increases cAMP levels and elevates cytosolic Ca/sup 2 +/ levels by degradation of polyphosphoinositides. The phorbol ester 12-0-tetradecanoyl phorbol 13-acetate (TPA) inhibits glucagon-induced calcium mobilization, but not cAMP formation. TPA can thus be used to assess the role of Ca/sup 2 +/ and cAMP in the activation of mitochondrial processes. In isolated hepatocytes, glucagon increased the steady state NAD(P)H level, probably by activating mitochondrial Ca/sup 2 +/ dependent dehydrogenases. TPA inhibited the glucagon-induced NAD(P) reduction without affecting phosphorylase activation. The effects of glucagon and TPA on mitochondrial respiratory activity and calcium retention were tested after isolation of the mitochondria from perfused livers. Electron transport rates were increased by 15-25% and calcium retention time was increased four-fold after glucagon treatment. When livers were pretreated with TPA, glucagon had no effect on electron transport activity, but calcium retention was increased by the same factor. The results suggest that glucagon-induced calcium mobilization is required for the stimulation of the respiratory activity but not for the increased capacity to retain a calcium overload in the mitochondria.

Research Organization:
Thomas Jefferson Univ. Medical School, Philadelphia, PA
OSTI ID:
6065805
Report Number(s):
CONF-870644-
Journal Information:
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
Country of Publication:
United States
Language:
English

Similar Records

Glucagon effects on the membrane potential and calcium uptake rate of rat liver mitochondria
Journal Article · Fri Aug 10 00:00:00 EDT 1984 · J. Biol. Chem.; (United States) · OSTI ID:5205341
Induction of rat hepatic zinc thionein by phorbol ester-mediated protein kinase C pathway
Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) · OSTI ID:5176491
Indirubin-3'-oxime impairs mitochondrial oxidative phosphorylation and prevents mitochondrial permeability transition induction
Journal Article · Sun Nov 30 23:00:00 EST 2008 · Toxicology and Applied Pharmacology · OSTI ID:21180483

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH METAL COMPOUNDS
AMP
BIOLOGICAL EFFECTS
BIOLOGICAL FUNCTIONS
BODY
CALCIUM COMPOUNDS
CARCINOGENS
CELL CONSTITUENTS
COENZYMES
DIGESTIVE SYSTEM
ELECTRON TRANSFER
ENZYMES
ESTERS
FUNCTIONS
GLANDS
GLUCAGON
HORMONES
INHIBITION
LIPIDS
LIVER
MEMBRANE TRANSPORT
METABOLISM
MITOCHONDRIA
NADP
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
ORGANS
OXIDOREDUCTASES
PEPTIDE HORMONES
PEPTIDES
PHORBOL ESTERS
PHOSPHOLIPIDS
POLYPEPTIDES
PROTEINS