Insulin receptors in rat brain: insulin stimulates phosphorylation of its receptor beta-subunit.
In rat brain cortex synaptosomes insulin stimulated the phosphorylation of its own receptor beta-subunit (94 kDa) as identified by immunoprecipitation with anti-insulin or anti-receptor antiserum. The receptor alpha-subunit (115 kDa) was characterized by specific labeling with 125I-labeled photoreactive insulin. These observations indicate that: (i) insulin receptors in brain are composed of alpha-subunits which bind insulin, and beta-subunits, the phosphorylation of which can be stimulated by insulin; (ii) the size of alpha-subunits in brain is significantly smaller than in other tissues (115 vs 130 kDa), whereas beta-subunits (94 kDa) are identical. We suggest that brain insulin receptors represent a subtype regarding their binding function, whereas their enzyme function is more conserved.
D000345:Affinity Labels / Q000378:metabolism; D000818:Animals; D001386:Azides / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007328:Insulin / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D007330:Insulin Antibodies; D046911:Macromolecular Substances; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains; D011972:Receptor, Insulin / Q000378:metabolism*; D012995:Solubility; D013574:Synaptosomes / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D000345:Affinity Labels; D001386:Azides; D007328:Insulin; D007330:Insulin Antibodies; D046911:Macromolecular Substances; D014660:Vasoactive Intestinal Peptide; C035459:insulin, (2-nitro-4-azidophenylacetyl)(B2)-des-Phe(B1)-; D004492:Edetic Acid; D011972:Receptor, Insulin