Related Experiment Video
Updated: Feb 5, 2026
07:00
A Method to Study the C924T Polymorphism of the Thromboxane A2 Receptor Gene
Published on: April 1, 2019
10.4K
P-glycoprotein polymorphism and levothyroxine bioavailability in hypothyroid patients
Ezgi Öztaş1, Alejandro Parejo Garcia-Saavedra1, Fatih Yanar2
1Istanbul University, Faculty of Pharmacy, Department of Pharmaceutical Toxicology, 34116 Beyazit, Istanbul, Turkey.
Summary
This study found no significant association between common ABCB1 gene single nucleotide polymorphisms (SNPs) and Levothyroxine (L-T4) dosage requirements in hypothyroid patients. Further research with larger cohorts is needed to clarify MDR1 polymorphism
Area of Science:
- Pharmacogenomics
- Endocrinology
- Molecular Biology
Background:
- P-glycoprotein (P-gp), encoded by the MDR1 (ABCB1) gene, influences drug disposition.
- Single nucleotide polymorphisms (SNPs) in MDR1 may alter P-gp activity, impacting drug efficacy and dosage.
- Personalized medicine aims to optimize treatment responses by considering individual genetic variations.
Purpose of the Study:
- To investigate the association between three common MDR1 gene SNPs (C1236T, G2677T/A, C3435T) and Levothyroxine (L-T4) dosage requirements.
- To assess the impact of MDR1 polymorphisms on achieving physiological thyroid hormone levels in post-thyroidectomy hypothyroid patients.
Main Methods:
- Genotyping of 90 post-thyroidectomy hypothyroid patients using real-time PCR.
- DNA samples were isolated from venous blood.
- Thyroid hormone levels were measured in routine biochemistry labs.
Main Results:
- Minor allele frequencies for C1236T, G2677T/A, and C3435T were 0.48, 0.51, and 0.51, respectively.
- Major haplotypes identified were T1236T2677T3435 (50.2%) and C1236G2677C3435 (32.6%).
- No significant association was found between MDR1 polymorphisms and L-T4 dosage needed to maintain normal thyroid hormone levels.
Conclusions:
- The studied MDR1 polymorphisms do not appear to significantly influence Levothyroxine dosage requirements.
- Conflicting previous reports necessitate further large-scale studies to elucidate the role of MDR1 polymorphisms in drug disposition.
Related Concept Videos
01:15Bioavailability Study Design: Healthy Subjects Versus Patients
160
Bioavailability studies are essential for evaluating a drug's therapeutic efficacy and understanding its absorption patterns under various physiological conditions. Conducting such studies on target patient populations provides more relevant data by simulating real-world disease states. However, practical challenges often necessitate the use of young, healthy adult volunteers as study subjects.Patients may exhibit altered drug absorption patterns due to the effects of the disease itself,...
160
01:17Bioavailability: Overview
447
Bioavailability refers to the proportion of an administered drug that reaches the systemic circulation in its active, unaltered form. It is a crucial pharmacokinetic parameter that determines the effectiveness of a drug in achieving its intended therapeutic outcomes. The route of administration significantly influences bioavailability, with intravenous administration achieving 100% bioavailability as the drug directly enters the bloodstream. In contrast, oral administration often results in...
447
01:13Bioavailability: Overview
4.5K
Bioavailability refers to the proportion of an unaltered drug that, after administration, enters the systemic circulation and can be distributed to the desired action site. Factors such as gastrointestinal (GI) absorption and liver biotransformation influence the bioavailability of a drug when it is administered orally. When a drug is administered intravenously, it enters the systemic circulation directly; by definition, its bioavailability is assumed to be 100%. The bioavailability of an...
4.5K
01:27Bioavailability Study Design: Absolute Versus Relative Bioavailability
362
Bioavailability is a crucial pharmacokinetic parameter that quantifies the proportion of an administered drug that reaches the systemic circulation and is available for therapeutic action. Regulatory agencies mandate the assessment of bioavailability, typically measured as the area under the drug plasma concentration-versus-time curve (AUC), to ensure the efficacy and safety of pharmaceutical products. These evaluations are categorized as absolute and relative bioavailability studies.Absolute...
362
01:21Matrix Proteoglycans and Glycoproteins
5.1K
Proteoglycans are extensively glycosylated proteins, commonly found in the extracellular matrix, interwoven with collagen fibers. Hyaline cartilage, the most common type of cartilage in the body, consists of short and dispersed collagen fibers associated with large amounts of proteoglycans. These proteoglycans have long negative charges that attract cations, which in turn attract water molecules. This influx of ions and water molecules swells up the proteoglycan like a water-soaked gel that can...
5.1K
01:22Bioavailability Enhancement: Determination and Conceptual Approaches in Overcoming Bioavailability Problems
212
Body:Bioavailability is a critical pharmacological concept that measures the extent and rate at which an active drug ingredient or therapeutic moiety enters the systemic circulation, remaining unchanged. It's a pivotal factor in determining a drug's efficacy and safety.The Biopharmaceutics Classification System (BCS) plays an essential role in drug development by categorizing drugs into four classes based on their solubility and permeability. This classification aids in understanding drug...
212