Related Experiment Video

Updated: Aug 12, 2026

Mixed Primary Cultures of Murine Small Intestine Intended for the Study of Gut Hormone Secretion and Live Cell Imaging of Enteroendocrine Cells
09:16

Mixed Primary Cultures of Murine Small Intestine Intended for the Study of Gut Hormone Secretion and Live Cell Imaging of Enteroendocrine Cells

Published on: April 20, 2017

Intracellular (Golgi) receptors for insulinlike peptides in rat liver

B I Posner, R M Gonzalez, H J Guyda

    Canadian Journal of Biochemistry
    |October 1, 1980
    PubMed

    An insulinlike peptide (ILAs) has been isolated in our laboratory from human serum. The binding of 123I-labeled ILAs was studied in subcellular fractions from rat liver and found to be much greater in microsomes than purified plasmalemma. The high level of microsomal binding was due to a particular enrichment of binding sites in Golgi elements. Binding to Golgi was time and temperature dependent and was augmented by an increase of either subcellular fraction or 125I-labeled ILAs in accordance with a mass action process. Degradation of 125I-labeled ILAs was greatest in the Golgi vesicle fraction and was reduced by incubation at 4 degrees C. Bound 125I-labeled ILAs could be eluted and was found to retain integrity. Binding was pH dependent with a broad optimum at pH 7.7-8.5. Dissociation of bound 125I-labeled ILAs was time and temperature dependent. It was greater at 37 than 4 degrees C, and was uninfluenced by unlabeled ILAs. The ILAs receptor was stable at 4 degrees C but was markedly decreased by preincubation at 37 degrees C. The binding of 125I-labeled ILAs was inhibited by unlabeled ILAs and related insulinlike peptides (the insulinlike growth factors, IGF-1 and IGF-2) in a dose-dependent manner. Insulin and its analogues had only a partially inhibitory effect, and structurally unrelated peptides were without inhibitory efficacy. In contrast ILAs and IGF-1 and IGF-2 inhibited 125I-labeled insulin binding to its receptors in a dose-dependent fashion. These observations identify a receptor for insulinlike peptides in the Golgi elements of rat liver. It is distinct from the insulin receptor previously observed in these elements. The dual interaction of ILAs and other insulinlike peptides with both the insulin receptor and their own unique receptor constitutes the presumed biochemical basis for the two types of action effected by this family of peptides, namely, an effect on metabolism comparable to insulin and an effect on cellular anabolism and growth.

    More Related Videos

    Mechanisms Underlying Gut Hormone Secretion Using the Isolated Perfused Rat Small Intestine07:00

    Mechanisms Underlying Gut Hormone Secretion Using the Isolated Perfused Rat Small Intestine

    Published on: February 26, 2019

    Precise Visualization of Insulin Receptors A and B in Murine Brain with an RNA In Situ Hybridization Assay08:34

    Precise Visualization of Insulin Receptors A and B in Murine Brain with an RNA In Situ Hybridization Assay

    Published on: July 15, 2025

    Related Concept Videos

    Intracellular Hormone Receptors01:08

    Intracellular Hormone Receptors

    Lipid-soluble hormones diffuse across the plasma and nuclear membrane of target cells to bind to their specific intracellular receptors. These receptors act as transcription factors that regulate gene expression and protein synthesis in the target cell
    Insulin Secretory Vesicles01:05

    Insulin Secretory Vesicles

    Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
    IP3/DAG Signaling Pathway01:11

    IP3/DAG Signaling Pathway

    Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the  phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...
    Glucose Homeostasis: Pancreatic Islets and Insulin Secretion01:27

    Glucose Homeostasis: Pancreatic Islets and Insulin Secretion

    The pancreatic islets comprising only 1%-2% of the volume are highly vascularized and innervated mini-organs. They contain five endocrine cell types, including β cells that secrete insulin, which is synthesized as a single polypeptide chain, preproinsulin, processed to proinsulin, and finally to insulin and C-peptide. This process is complex and regulated, involving the Golgi complex, the endoplasmic reticulum, and the secretory granules of the β cell.
    Insulin and C-peptide are co-secreted in...
    Insulin: The Receptor and Signaling Pathways01:28

    Insulin: The Receptor and Signaling Pathways

    Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...
    Glucagon-like Receptor Agonists01:24

    Glucagon-like Receptor Agonists

    Incretins include glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which stimulate insulin secretion post-meals. In type 2 diabetes, GIP's efficacy is reduced, making GLP-1 a viable drug target. GIP originates from preproGIP.
    GLP-1, when administered in high doses intravenously, triggers insulin secretion, inhibits glucagon release, slows gastric emptying, reduces food intake, and restores normal insulin secretion. However, its rapid inactivation by the...