Identification and characterization of insulin receptors in basolateral membranes of dog intestinal mucosa

Journal Article · Thu Oct 01 00:00:00 EDT 1987 · Diabetes; (United States)

DOI:https://doi.org/10.2337/diab.36.10.1124· OSTI ID:5857005

Gingerich, R L; Gilbert, W R; Comens, P G; Gavin, III, J R

Little is known about hormonal regulation of substrate transport and metabolism in the mucosal lining of the small intestine. Because insulin regulates these functions in other tissues by binding to its receptor, we have investigated the presence of insulin receptors in canine small intestinal mucosa with basolateral membranes (BLM) and brush border membranes (BBM) prepared by sorbitol density centrifugation. A14-(/sup 125/I)iodoinsulin was used to study binding and structural characteristics of specific insulin receptors in BLM. Analysis of receptors in BLM identified binding sites with high affinity (Kd 88 pM) and low capacity (0.4 pmol/mg protein) as well as with low affinity (Kd 36 nM) and high capacity (4.7 pmol/mg protein). Binding was time, temperature, and pH dependent, and /sup 125/I-labeled insulin dissociation was enhanced in the presence of unlabeled insulin. Cross-reactivity of these receptors to proinsulin, IGF-II, and IGF-I was 4, 1.8, and less than 1%, respectively. Covalent cross-linking of labeled insulin to BLM insulin receptors with disuccinimidyl suberate revealed a single 135,000-Mr band that was completely inhibited by unlabeled insulin. There was a 16-fold greater specific binding of insulin to BLM (39.0 +/- 2.4%) than to BBM (2.5 +/- 0.6%). These results demonstrate the presence of a highly specific receptor for insulin on the vascular, but not the luminal, surface of the small intestinal mucosa in dogs, and suggest that insulin may play an important role in the regulation of gastrointestinal physiology.

• Research Organization: Washington Univ. School of Medicine, St Louis, MO
• OSTI ID: 5857005
• Journal Information: Diabetes; (United States), Journal Name: Diabetes; (United States) Vol. 36:10; ISSN DIAEA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AFFINITY
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL FUNCTIONS
BODY
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL COMPOSITION
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DOGS
ELECTRON CAPTURE RADIOISOTOPES
FUNCTIONS
GASTROINTESTINAL TRACT
HORMONES
INSULIN
INTERMEDIATE MASS NUCLEI
INTESTINES
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SMALL INTESTINE
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRACER TECHNIQUES
VERTEBRATES