Ontogeny of rat hepatic adrenoceptors
Hepatic alpha-1, alpha-2 and beta-2 adrenoceptors were characterized during development of the rat through Scatchard analysis of (3H)prazosin, (3H)rauwolscine and (125I)pindolol binding to liver membrane preparations. Major changes in adrenoceptor numbers occur shortly before birth at weaning. The fetal rat liver is characterized by a large number of alpha-2 adrenoceptors, which falls 10-fold by birth. The number of hepatic beta-2 adrenoceptors decreases gradually during development, and is lower at all times than the number of alpha-1 and alpha-2 adrenoceptors. The developmental profile of the hepatic alpha-1 adrenoceptor is biphasic: there is a 2 to 3-fold fall in alpha-1 adrenoceptor number at birth and a 3- to 5-fold rise at weaning. While absolute numbers of alpha-1 and beta-2 adrenoceptors do not correlate precisely with reported actions of epinephrine and norepinephrine on hepatic metabolism during ontogeny, the increasing ratio of alpha-1/beta-2 hepatic adrenoceptors may contribute to the conversion from predominantly beta effects of catecholamines reported in fetal and suckling rat liver to the predominantly alpha-1 effects that are well documented in the adult male rat.
- OSTI ID:
- 6748709
- Journal Information:
- J. Pharmacol. Exp. Ther.; (United States), Vol. 227:1
- Country of Publication:
- United States
- Language:
- English
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ADRENAL HORMONES
RECEPTORS
LIVER
METABOLISM
ONTOGENESIS
BIOCHEMICAL REACTION KINETICS
CELL MEMBRANES
CHEMICAL BONDS
FETUSES
IODINE 125
LABELLED COMPOUNDS
RATS
TISSUE CULTURES
TRITIUM COMPOUNDS
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
GLANDS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIOISOTOPES
REACTION KINETICS
RODENTS
STEROID HORMONES
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques