Abstract
Insulin receptor (IR)-deficient pups rapidly become hyperglycemic and hyperinsulinemic and die of diabetic ketoacidosis within a few days. Immunocytochemical analysis of the endocrine pancreas revealed that IR deficiency did not alter islet morphology or the number of beta-, alpha-, delta-, and pancreatic polypeptide (PP) cells. The lack of IR did not result in major changes in the expression of islet hormone genes or of beta-cell-specific marker genes encoding pancreas duodenum homeobox-containing transcription factor-1 (PDX-1), glucokinase (GCK), and GLUT2, as shown by reverse transcriptase-polymerase chain reaction analysis. The serum glucagon levels in IR-deficient and nondiabetic littermates were comparable. Finally, total insulin content in the pancreas of IR-deficient pups was gradually depleted, indicating sustained insulin secretion, not compensated for by increased insulin biosynthesis. These findings are discussed in light of recent results suggesting a role of IR in beta-cell function.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Animals, Newborn
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Female
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Gene Expression
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Genotype
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Glucagon / genetics
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Glucagon / metabolism
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Glucokinase / genetics
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Glucose Transporter Type 2
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Homeodomain Proteins*
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Hyperinsulinism / genetics
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Hyperinsulinism / metabolism
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Immunohistochemistry
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Insulin / genetics
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Insulin / metabolism
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Islets of Langerhans / chemistry
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Islets of Langerhans / metabolism*
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Male
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Mice
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Mice, Knockout
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Mice, Mutant Strains
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Monosaccharide Transport Proteins / genetics
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Pancreatic Polypeptide / genetics
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Pancreatic Polypeptide / metabolism
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Phenotype
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Receptor, Insulin / deficiency
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Receptor, Insulin / genetics*
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Reverse Transcriptase Polymerase Chain Reaction
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Somatostatin / genetics
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Somatostatin / metabolism
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Trans-Activators / genetics
Substances
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Glucose Transporter Type 2
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Homeodomain Proteins
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Insulin
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Monosaccharide Transport Proteins
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RNA, Messenger
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Trans-Activators
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pancreatic and duodenal homeobox 1 protein
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Somatostatin
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Pancreatic Polypeptide
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Glucagon
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Glucokinase
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Receptor, Insulin