In situ autoradiography and ligand-dependent tyrosine kinase activity reveal insulin receptors and insulin-like growth factor I receptors in prepancreatic chicken embryos

Journal Article · Tue Aug 01 04:00:00 EDT 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.86.15.5868· OSTI ID:5161756

Girbau, M; Bassas, L; Alemany, J; de Pablo, F ^[1]

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1. Hospital Santa Cruz y San Pablo, Barcelona (Spain)

We previously reported specific cross-linking of 125I-labeled insulin and 125I-labeled insulin-like growth factor I (IGF-I) to the alpha subunit of their respective receptors in chicken embryos of 20 somites and older. To achieve adequate sensitivity and localize spatially the receptors in younger embryos, we adapted an autoradiographic technique using whole-mounted chicken blastoderms. Insulin receptors and IGF-I receptors were expressed and could be localized as early as gastrulation, before the first somite is formed. Relative density was analyzed by a computer-assisted image system, revealing overall slightly higher binding of IGF-I than of insulin. Structures rich in both types of receptors were predominantly of ectodermal origin: Hensen's node in gastrulating embryos and neural folds, neural tube and optic vesicles during neurulation. The signal transduction capability of the receptors in early organogenesis was assessed by their ability to phosphorylate the exogenous substrate poly(Glu80Tyr20). Ligand-dependent tyrosine phosphorylation was demonstrable with both insulin and IGF-I in glycoprotein-enriched preparations from embryos at days 2 through 6 of embryogenesis. There was a developmentally regulated change in ligand-dependent tyrosine kinase activity, with a sharp increase from day 2 to day 4, in contrast with a small increase in the ligand binding. Binding of 125I-labeled IGF-I was, with the solubilized receptors, severalfold higher than binding of 125I-labeled insulin. However, the insulin-dependent phosphorylation was as high as the IGF-I-dependent phosphorylation at each developmental stage.

• OSTI ID: 5161756
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 86:15; ISSN PNASA; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
BIRDS
BODY
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHICKENS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
EMBRYOS
ENDOCRINE GLANDS
ENZYME ACTIVITY
ENZYMES
FOWL
GLANDS
GROWTH FACTORS
HORMONES
HYDROXY ACIDS
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
LIGANDS
MEMBRANE PROTEINS
MITOGENS
NUCLEI
ODD-EVEN NUCLEI
ONTOGENESIS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PANCREAS
PEPTIDE HORMONES
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHORYLATION
PHOSPHOTRANSFERASES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
TRANSFERASES
TYROSINE
VERTEBRATES