Serum and intracellular retinol in the equine.
Abstract: 1. Serum and intracellular distribution of retinol was determined in equines maintained on four levels of vitamin A intake. 2. The form of retinol transported in serum was determined by gel filtration and chromatography to be a complex of retinol bound to a protein of molecular weight (MW) of approximately 20000, which was in turn complexed probably with prealbumin to yield a complex with a MW of 75000 to 80000. 3. Increasing dietary vitamin A levels enhanced the concentration of lipoprotein-bound retinyl esters in the plasma. 4. Vitamin A in the liver cytosol was found predominantly as retinyl esters in a lipid-protein aggregate of MW approximately 2 X 10(6) and hydrated density of 1.063-1.111. In the kidney and adrenal gland, two lipid-protein entities were found with MW of approximately 1.8 X 10(6) and 1.7 X 10(6) respectively. These fractions contained approximately 40 and 20% lipid respectively and had densities of 1.063-1.111 and approximately 1.21. 5. All lipid-protein aggregates were associated with retinyl palmitate hydrolase activity and guanidine treatment released a 15000 MW material, presumably intracellular retinol-binding protein. 6. Increasing dietary vitamin A enhanced the proportion of retinol in the 1.7 X 10(6) fraction. 7. Findings in equine plasma and liver resemble previous observations in other species. The characterization of two new lipid-protein aggregates in equine kidney and adrenal glands, which have hydrolase activity, may be important in intracellular retinal transport and metabolism, especially in animals subjected to high intakes of vitamin A.
Publication Date: 1982-03-01 PubMed ID: 7199935DOI: 10.1079/bjn19820036Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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This research study explores the distribution of a form of Vitamin A, called retinol, in the blood and cells of horses, and how this distribution changes based on different dietary intakes of Vitamin A.
Understanding the Research
The study involved examining the presence and role of retinol in the blood and cells of horses, considering different quantities of vitamin A intake. Key aspects of the research include:
- Determination of retinol distribution in serum and within cells. Serum refers to the fluid and solute component of blood, which does not play a role in clotting and can be obtained by full coagulation of blood. The researchers analyzed these distributions across horses subjected to four different levels of Vitamin A consumption. This helped understand how diets with varying Vitamin A levels impact the body’s handling of retinol.
- Identification of Retinol’s form in serum. Through techniques like gel filtration and chromatography, the researchers identified retinol was complexed (or bound together) with a protein having a molecular weight of around 20000. This complex was further bound with prealbumin, resulting in a more massive complex. Understanding these binding behaviors helps trace the movement and usage of retinol within the body.
- Increase in dietary Vitamin A lead to higher concentration of lipoprotein-bound retinyl esters in plasma. This implies that higher Vitamin A intake correlates with increased transportation of retinol in the blood.
- Detecting presence of retinol in liver cytosol, kidney & adrenal glands. The researchers found Vitamin A mostly as retinyl esters in these organs, forming lipid-protein clusters of specific weights and densities. These complex aggregates were exhibited retinyl palmitate hydrolase activity, which is crucial in metabolizing retinol. These findings provide new perspectives on how Vitamin A is stored and metabolized in different organs.
Implications of the Research
This research furthers understanding of how Vitamin A is processed and used in the body, offering important insights for equine health and nutrition. With knowledge of how increasing Vitamin A intake affects retinol distribution and metabolism, dietary plans can be created or adjusted to provide optimal health benefits.
In addition to equine wellness, these findings might be beneficial to other fields. Since the retinol behavior observed in equines resembles that in other species, these insights potentially impact wider veterinary sciences and, even, human health studies.
Cite This Article
APA
Sklan D, Donoghue S.
(1982).
Serum and intracellular retinol in the equine.
Br J Nutr, 47(2), 273-280.
https://doi.org/10.1079/bjn19820036 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Biological Transport
- Carboxylic Ester Hydrolases / metabolism
- Female
- Horses / metabolism
- Palmitates / metabolism
- Retinol-Binding Proteins / metabolism
- Retinol-Binding Proteins, Plasma
- Tissue Distribution
- Vitamin A / administration & dosage
- Vitamin A / adverse effects
- Vitamin A / analogs & derivatives
- Vitamin A / metabolism
- Vitamin A Deficiency / metabolism
Grant Funding
- 5 S07 RR 5464 / NCRR NIH HHS
Citations
This article has been cited 1 times.- Blakley BR, Bell RJ. The vitamin A and vitamin E status of horses raised in Alberta and Saskatchewan. Can Vet J 1994 May;35(5):297-300.
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