Hepatic receptors for homologous growth hormone in the eel

Journal Article · Fri Mar 01 04:00:00 EST 1991 · General and Comparative Endocrinology; (United States)

DOI:https://doi.org/10.1016/0016-6480(91)90165-3· OSTI ID:5272275

Hirano, T ^[1]

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1. Univ. of Tokyo, (Japan)

The specific binding of 125I-labeled eel growth hormone (eGH) to liver membranes of the eel was examined. The specific binding to the 10,000g pellet was greater than that to the 600g pellet. The specific binding was linear up to about 100 mg fresh tissue, and was saturable with increasing amounts of membrane. The specific binding was pH-, temperature-, and time-dependent, with the optimum pH at 7.4, and greater specific binding was obtained at 15 and 25 degrees than at 35 degrees. Scatchard analysis of liver binding gave an association constant of 1.1 x 10(9) M-1 and a capacity of 105 fmol/mg protein. The receptor preparation was highly specific for GHs. Natural and recombinant eel GHs as well as recombinant salmon GH competed equally with 125I-eGH for the receptor sites of the 10,000g liver membrane. Ovine GH was more potent in displacing the labeled eGH than the homologous eel hormone. Tilapia GH and ovine prolactin (PRL) were needed in greater amounts (40 times) than eGH to displace the labeled eGH. Salmon and tilapia PRLs were still less potent (500 times) than eGH. There was no displacement with eel PRL. No significant change in the specific binding was seen 1 week after hypophysectomy, whereas injection of eGH into the hypophysectomized eel caused a significant reduction after 24 hr. The binding to the membrane fractions from gills, kidney, muscle, intestine, and brain was low and exclusively nonspecific, indicating the presence of specific GH receptors predominantly in the liver.

• OSTI ID: 5272275
• Journal Information: General and Comparative Endocrinology; (United States), Journal Name: General and Comparative Endocrinology; (United States) Vol. 81:3; ISSN 0016-6480; ISSN GCENA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AQUATIC ORGANISMS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CELL CONSTITUENTS
CELL MEMBRANES
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
EEL
ELECTRON CAPTURE RADIOISOTOPES
FISHES
GLANDS
HORMONES
HYPOPHYSECTOMY
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIVER
MEDICINE
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
STH
SURGERY
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRACER TECHNIQUES
VERTEBRATES