Related Experiment Video
Updated: May 5, 2026
07:34
Quantitative Determination of De Novo Fatty Acid Synthesis in Brown Adipose Tissue Using Deuterium Oxide
Published on: May 12, 2023
1.7K
Phenylalanine kinetics in human adipose tissue
S W Coppack1, M Persson, J M Miles
1Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905.
The Journal of Clinical Investigation
|August 1, 1996
Summary
Adipose tissue significantly contributes to phenylalanine release, which decreases during glucose infusion. This protein metabolism regulation in adipose tissue is sensitive to high insulin levels.
Area of Science:
- Metabolic regulation
- Human physiology
- Nutrient metabolism
Background:
- Protein metabolism in adipose tissue is poorly understood.
- Adipose tissue plays a role in overall amino acid balance.
- Understanding nutrient regulation in fat tissue is crucial for metabolic health.
Purpose of the Study:
- To investigate the regulation of protein metabolism in adipose tissue.
- To quantify the contribution of adipose tissue to systemic phenylalanine kinetics.
- To determine the effect of glucose infusion on phenylalanine release from adipose tissue.
Main Methods:
- Infusion of [3H]phenylalanine in healthy volunteers.
- Blood sampling from radial artery, abdominal vein, and forearm vein.
- Measurement of adipose tissue and forearm blood flow using 133Xe and plethysmography.
- Determination of body fat mass via dual-energy x-ray absorptiometry.
Main Results:
- Glucose infusion significantly increased glucose and insulin levels.
- Systemic phenylalanine appearance decreased during glucose infusion.
- Adipose tissue phenylalanine release decreased significantly during glucose infusion.
- Forearm phenylalanine release remained unchanged.
Conclusions:
- Adipose tissue is a significant, albeit small, contributor to systemic phenylalanine appearance.
- Phenylalanine release from adipose tissue is sensitive to hyperinsulinemia, similar to lipolysis.
- These findings shed light on the role of adipose tissue in protein metabolism regulation.
More Related Videos
Related Concept Videos
01:25cAMP-dependent Protein Kinase Pathways
7.3K
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
7.3K
01:20Inborn Errors of Metabolism
1.1K
Phenylketonuria (PKU) is a protein metabolism disorder characterized by high blood levels of the amino acid phenylalanine. This results from a mutation in the gene responsible for phenylalanine hydroxylase, an enzyme that converts phenylalanine into tyrosine. When this enzyme is deficient, phenylalanine builds up in the blood, leading to symptoms such as vomiting, rashes, seizures, growth deficiency, and severe mental retardation. An early diagnosis and a diet restricting phenylalanine intake...
1.1K
01:20Pharmacokinetics in Obese Patients: Drug Metabolism and Excretion
324
Drug metabolism, a critical process in the liver, involves two primary phases: Phase I reactions and Phase II conjugation. Obesity introduces significant alterations in this metabolic process, primarily due to fatty infiltration of the liver, leading to conditions such as nonalcoholic fatty liver disease (NAFLD). This condition can modify the activities of both Phase I and II enzymes, impacting how drugs are metabolized in obese patients.Phase I metabolism sees variable effects across...
324
01:24Pharmacokinetics in Pediatric Patients: Drug Metabolism
410
In pediatric care, understanding the nuances of hepatic drug metabolism is crucial, as it significantly differs from that of adults. This divergence is primarily due to the developmental stage of drug-metabolizing enzymes, which affects how medications are processed in the body. In neonates, for instance, the activity of Phase I enzymes—critical for the initial breakdown of drugs—is markedly reduced, functioning at just 20–40% of the levels seen in adults. This reduction poses...
410
01:11Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
81
Genetic polymorphisms in drug targets have emerged as critical determinants of interindividual variability in drug response and toxicity. Pharmacogenomic investigations increasingly focus on identifying these variations to personalize and optimize therapeutic interventions. A drug target may be a receptor, enzyme, or signaling protein involved in pharmacologic responses or disease-related pathways. While early pharmacogenetic studies focused primarily on drug metabolism, current research...
81