Related Experiment Video
Updated: May 10, 2026
08:03
Glucose Uptake Measurement and Response to Insulin Stimulation in In Vitro Cultured Human Primary Myotubes
Published on: June 25, 2017
Testosterone increases GLUT4-dependent glucose uptake in cardiomyocytes
Carlos Wilson1, Ariel Contreras-Ferrat, Nataly Venegas
1Programa de Fisiología y Biofísica y Programa de Biología Celular y Molecular, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.
Journal of Cellular Physiology
|June 13, 2013
Summary
Testosterone enhances glucose uptake in heart cells (cardiomyocytes) by increasing glucose transporter 4 (GLUT4) on the cell surface. This process is regulated by CaMKII and AMPK signaling pathways, impacting energy production.
Area of Science:
- Cardiovascular Physiology
- Endocrinology
- Cellular Metabolism
Background:
- Testosterone significantly influences cardiac function, affecting cardiomyocytes through rapid and long-term mechanisms.
- Cardiomyocytes primarily utilize fatty acids but can increase glucose uptake for energy optimization.
- Understanding testosterone's metabolic effects on cardiomyocytes is crucial for cardiac health.
Purpose of the Study:
- To investigate the impact of testosterone on glucose uptake in cardiomyocytes.
- To elucidate the specific molecular pathways involved in testosterone-mediated glucose uptake.
Main Methods:
- Measured glucose uptake using fluorescent and radiolabeled analogs in cultured cardiomyocytes.
- Utilized GLUT4 inhibitor (indinavir) and assessed GLUT4 translocation via transfected GLUT4myc-eGFP.
- Examined the roles of intracellular signaling pathways, including Akt, CaMKII, and AMPK, using specific inhibitors and genetic silencing.
Main Results:
- Testosterone significantly increased glucose uptake in cardiomyocytes, dependent on glucose transporter 4 (GLUT4).
- Testosterone promoted the translocation of GLUT4 to the cardiomyocyte plasma membrane.
- The testosterone-induced glucose uptake and GLUT4 translocation were mediated by Ca(2+)/calmodulin protein kinase II (CaMKII) and AMP-activated protein kinase (AMPK), but not Akt.
Conclusions:
- Testosterone stimulates GLUT4-dependent glucose uptake in cardiomyocytes via CaMKII and AMPK signaling.
- This mechanism may represent a key pathway through which testosterone influences cardiomyocyte energy production and protein synthesis.
- Testosterone's effects on cardiac metabolism are partly mediated by enhanced glucose utilization.
Related Concept Videos
01:16Hormones Regulating Blood Glucose
Insulin is released by beta cells of the pancreas when blood glucose levels are high. It facilitates glucose absorption and utilization in insulin-dependent cells with insulin receptors on their plasma membranes. Insulin promotes glucose uptake by increasing the number of glucose transport proteins in the cell membrane, allowing glucose to enter the cell. As a result, glucose utilization and ATP production are enhanced.
In addition to accelerating glucose uptake and utilization, insulin has...
In addition to accelerating glucose uptake and utilization, insulin has...
01:02Glucose Homeostasis: Regulation of Blood Glucose
Carbohydrates consumed through foods are converted into glucose, a crucial energy source for the body. In the prandial state, high blood glucose levels stimulate the secretion of insulin from the pancreas. Insulin inhibits hepatic glucose production and stimulates glucose uptake and metabolism by muscle and adipose tissue. The excess glucose is converted into glycogen and stored in the liver and muscles.
During fasting, when blood glucose levels are low, the pancreas secretes glucagon. it...
During fasting, when blood glucose levels are low, the pancreas secretes glucagon. it...
01:27Glucose 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 and C-peptide are co-secreted in...
01:26Glucose Absorption Into the Small Intestine
Complex carbohydrates consumed cannot be absorbed into the small intestine in their original form. First, they must be hydrolyzed to a monosaccharide form such as glucose or galactose. These monosaccharides are then transported across the intestinal membrane and into the blood via transcellular transport. The intestinal epithelial cells allow the movement of these monosaccharides with a defined 'entry' through membrane transporter proteins present on their apical membrane and 'exit' via the...
01:27Glucose Transporters
Glucose transporters facilitate the transport of glucose across the cell membrane. In addition to glucose, some glucose transporters can also aid the movement of other hexoses such as fructose, mannose, and galactose.
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
01:05Insulin 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...