Effects of chronic oral administration on the disposition of laevodopa and its major metabolites in the plasma of the rat.

Xenobiotica; the Fate of Foreign Compounds in Biological Systems
L K Cheng, H L Fung

Abstract

1. Plasma levels of total radioactivity , unchanged laevodopa, catecholamines, 3-O-methyldopa and non-amino phenolic acids were measured in rats treated orally with [3H]laevodopa (100 mg/kg, 100 muCi/kg) for different periods of time. 2. Chronic oral administration of laevodopa for two months significantly delayed the appearance of peak plasma levels and decreased the overall plasma concentrations of the unchanged drug as compared to controls. The extent of absorption of an oral dose of [3H]laevodopa was not significantly impaired on chronic treatment and/or ageing. The decrease in the levels of unchanged laevodopa appeared to be due to an increase in the apparent volumes of distribution of the drug and its metabolites upon ageing. 3. The plasma levels of the catecholamine metabolite fraction, which included dopamine, noradrenaline, etc., were much higher in chronically dosed animals. 4. These findings may be relevant in the understanding of such clinical observations as decreasing therapeutic effects and increasing toxicity after long-term laevodopa treatment in human patients.

References

Oct 27, 1973·Lancet·K R HunterG M Stern
Nov 1, 1974·Clinical Pharmacology and Therapeutics·G M TyceM D Muenter
Apr 13, 1973·Nature·D N WadeJ L Morris
Jul 1, 1971·Journal of Pharmaceutical Sciences·C B CoutinhoT Crews
Feb 16, 1967·The New England Journal of Medicine·G C CotziasL M Schiffer

❮ Previous
Next ❯

Citations

Aug 1, 1993·The Journal of Pharmacy and Pharmacology·S RoseC D Marsden
Apr 1, 1976·Xenobiotica; the Fate of Foreign Compounds in Biological Systems·L K Cheng, H L Fung
Oct 1, 1978·Xenobiotica; the Fate of Foreign Compounds in Biological Systems·B L GoodwinM Sandler

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.