beta. -adrenergic receptor-mediated hepatic glycogenolysis is increased in aged male rats
The effect of age on catecholamine-stimulated glycogenolysis was studied in isolated hepatocytes prepared from 3, 12, and 24 month-old rats. Glucose release was stimulated by epinephrine and norepinephrine, this was inhibited by phentolamine and prazosin. Isoproterenol (ISO) stimulated glycogenolysis only in cells from 24 month-old rats, this was blocked by propranolol. In liver plasma membranes, binding of (/sup 3/H)yohimbine (100-130 fmol/mg protein) did not change with age, whereas (/sup 3/H)prazosin binding decreased from 870 fmol/mg at 3 months to 435 fmol/mg at 12 months, but subsequently rose to 656 fmol/mg at 24 months. (/sup 125/I)Cyanopindolol binding increased from 8 fmol/mg at 3 months to 19 fmol/mg at 24 months. The proportion of ..beta..-receptors in the high affinity state increased from 28% at 3 months to 42% at 24 months. ISO stimulated adenylate cyclase at 24 months but not at 3 months. Basal, fluoride-, GTP-, and Gpp(NH)p-stimulated activities were 1.4- to 2.4-fold greater at 24 months than at 3 months. These results suggest an age-related increase in the sensitivity of adenylate cyclase to ..beta..-receptor stimulation.
- Research Organization:
- Meharry Medical College, Nashville, TN
- OSTI ID:
- 6991762
- Report Number(s):
- CONF-8604222-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
Similar Records
Hormonal regulation of hepatic glycogenolysis in the carp, Cyprinus carpio
Characterization of beta-adrenergic receptors and adenylate cyclase activity in rat brown fat
Related Subjects
CYCLASES
ENZYME ACTIVITY
GLYCOGEN
METABOLISM
SYMPATHOMIMETICS
RECEPTORS
AGE DEPENDENCE
BIOCHEMICAL REACTION KINETICS
GLUCOSE
IODINE 125
LIVER CELLS
MALES
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALDEHYDES
ANIMAL CELLS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
CARBOHYDRATES
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
HEXOSES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LYASES
MAMMALS
MEMBRANE PROTEINS
MONOSACCHARIDES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
POLYSACCHARIDES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RODENTS
SACCHARIDES
SOMATIC CELLS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques