Sexual dimorphism in adrenergic regulation of hepatic glycogenolysis

Journal Article · Wed Apr 01 04:00:00 EST 1987 · Am. J. Physiol.; (United States)

OSTI ID:5716306

Studer, R K

The total phosphorylase a plus b of hepatocytes isolated from females and incubated in the absence or presence of estradiol and progesterone at concentrations found in vivo does not vary during the estrous cycle. However, there is a slight but significant influence of the estrous cycle on basal and epinephrine-stimulated phosphorylase a activity, with a nadir being seen on diestrus. The relative contributions of the ..cap alpha..- and ..beta..-mediated pathways to phosphorylase a activation do not vary with the estrous cycle but are constant at 75 and 56%, respectively, of the response to 5 x 10/sup -8/ M epinephrine. When the epinephrine-stimulated glucose release from glycogen stores in cells from females and males is compared, the release from the female is greater than that from the male, while the ..cap alpha..-receptor-mediated stimulation in the female is comparable with that in the male. The epinephrine-stimulated increase in cytostolic free calcium (Ca/sub i/) is greater in the male than the female at 10/sup -6/ M but greater in the female than the male at 5 x 10/sup -9/ M. The changes in Ca/sub i/ are equivalent at intermediate epinephrine concentrations. When considered with the prior analysis of /sup 45/Ca efflux after adrenergic stimulation, this suggests there may be a sexual dimorphism in hepatocyte calcium transport systems. The glucose release for a given increase in Ca/sub i/ is greater in the female than the male probably due to the concomitant action of the ..beta..-mediated increase in cAMP and the ..cap alpha..-mediated increase in Ca/sub i/. This supports the conclusion that the ..beta..-mediated component does make a significant contribution to the catecholamine regulation of glycogenolysis in hepatocytes from adult female rats.

• Research Organization: Univ. of Pittsburgh, PA
• OSTI ID: 5716306
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 252:4; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ADRENALINE
ALDEHYDES
ALKALINE EARTH ISOTOPES
ANIMAL CELLS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM 45
CALCIUM ISOTOPES
CARBOHYDRATES
CARDIOTONICS
CARDIOVASCULAR AGENTS
DAYS LIVING RADIOISOTOPES
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ENZYME ACTIVITY
ENZYMES
ESTRADIOL
ESTRANES
ESTROGENS
ESTROUS CYCLE
EVEN-ODD NUCLEI
FEMALES
GLUCOSE
GLYCOGEN
HEXOSES
HORMONES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOTOPES
KETONES
LIVER CELLS
MALES
MEMBRANE TRANSPORT
MONOSACCHARIDES
NEUROREGULATORS
NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
PHYSIOLOGY
POLYSACCHARIDES
PREGNANES
PROGESTERONE
RADIOISOTOPES
SACCHARIDES
SEX DEPENDENCE
SOMATIC CELLS
STEROID HORMONES
STEROIDS
SYMPATHOMIMETICS
TRANSFERASES