PMID: 758146Jan 1, 1979Paper

In vivo absorption and phosphorylation of pyridoxine . HCl in rat jejunum

Gastroenterology
H M Middleton

Abstract

The absorption and phosphorylation of 3H-pyridoxine . HCl were studied in vivo in isolated loops of rat jejunum. Uptake was rapid and linear over the concentration range of 0.2-1 mM; tissue content of absorbed vitamin was saturable and consisted primarily of phosphorylated forms of vitamin B6. Phosphorylation was saturable with a Km of 11.6 micronM and a Vmax of 1.65 nmol/5 min/g wet tissue. Inhibition of phosphorylation changed neither the t 1/2 of 3H-pyridoxine . HCl disappearance from the lumen nor the calculated uptake after either 5-min or 30-min absorption periods. Inhibition of phosphorylation, however, significantly decreased the t 1/2 for transmural absorption and significantly increased the calculated transmural absorption after a 5-min absorption period. These studies indicate that (a) pyridoxine absorption, over the concentration range tested, is nonsaturable and consistent with passive diffusion; (b) jejunal phosphorylation of pyridoxine occurs in vivo, is saturable, and results in saturation of tissue content of the absorbed vitamin; and (c) phosphorylation has no significant effect on the uptake of pyridoxine but significantly delays the transmural absorption of a finite amount of the vitamin.

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.