Demonstration of lactogenic receptors in rat endocrine pancreases by quantitative autoradiography

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Diabetes; (USA)

DOI:https://doi.org/10.2337/diab.39.9.1045· OSTI ID:6623029

Polak, M; Scharfmann, R; Ban, E; Haour, F; Postel-Vinay, M C; Czernichow, P ^[1]

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1. National Institute of Health and Medical Research, Paris (France)

A direct effect of growth hormone and/or prolactin on the growth of the pancreatic beta-cell has been proposed. This study assessed the presence of human growth hormone (hGH)-binding sites in male adult rat endocrine pancreas via quantitative autoradiography. The binding of 125I-labeled hGH was evaluated by receptor autoradiography on frozen-pancreas cryostat cut sections. The sections were incubated with 125I-hGH (10(-10) M) for 75 min at room temperature, and nonspecific binding was determined in the presence of excess native hGH (5 X 10(-7) M). The specificity of the binding was assessed in competition experiments with bovine GH and ovine prolactin. The autoradiograms were quantified with a computer-assisted image-processing system. The sections were then stained to visualize the endocrine islets. Nondiabetic control and streptozocin (STZ)-injected rats were used. Our results show that (1) there is specific binding of iodinated hGH in small areas of the pancreas, which appear as the Langerhans islets when the autoradiogram and the stained sections are superimposed; (2) the specificity of hGH binding in rat islets is lactogenic; (3) the density of the hGH-binding sites in the endocrine pancreas is estimated at 4.8 fmol/mg protein, with IC50 ranging from 0.98 to 2.50 nM; and (4) binding sites may be present on the beta-cell, because specific binding disappears in STZ-injected rats. In conclusion, by use of a quantitative autoradiographic technique, we provide evidence for the presence of lactogenic receptors on rat beta-cells.

• OSTI ID: 6623029
• Journal Information: Diabetes; (USA), Journal Name: Diabetes; (USA) Vol. 39:9; ISSN 0012-1797; ISSN DIAEA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BODY
CPB
DAYS LIVING RADIOISOTOPES
DIABETES MELLITUS
DIGESTIVE SYSTEM
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE DISEASES
ENDOCRINE GLANDS
GLANDS
GONADOTROPINS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LTH
MAMMALS
MEMBRANE PROTEINS
METABOLIC DISEASES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PANCREAS
PEPTIDE HORMONES
PITUITARY HORMONES
PROTEINS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
STH
VERTEBRATES