Navigation Links
Don't forget the vitamin A when working with its carrier protein

Vitamin A is an essential nutrient involved in vision, growth, cellular differentiation, and immune function. Because vitamin A is fat-soluble, it is chaperoned through the body on carrier proteins. Researchers at the University of Wisconsin-Madison in a study funded by USDA and NIH, discovered that not only was one of the carrier proteins for vitamin A, retinol-binding protein (RBP), elevated in obese individuals compared to leaner controls, but some of it was not attached to retinol, the main circulating form of the vitamin. RBP that is not bound to vitamin A is called apo-RBP by vitamin A scientists. Their study will appear in the October 08 issue of Experimental Biology and Medicine.

The research team led by Sherry Tanumihardjo, an associate professor of Nutritional Sciences, originally was interested in determining the degree of hypervitaminosis A in the cohort for preliminary data on excessive liver storage of the vitamin. Her graduate student, Jordan Mills, was interested in determining the retinol-binding protein concentrations. While the degree of hypervitaminosis A was remarkable at 4% prevalence for the obese cohort, the relationship of retinol to RBP was a more interesting discovery. The retinol to RBP ratio (retinol:RBP) was significantly lower in the obese subjects than nonobese subjects. This was attributable to more RBP circulating in the serum not bound to vitamin A. RBP was strongly associated with vitamin A in both groups, but more so in the nonobese individuals.

"A series of studies in mice and humans revealed a strong relationship between serum RBP and obesity-induced insulin resistance. While some studies validated these original observations of elevated RBP in obesity and insulin resistance in humans, others have not. Often lacking in these publications are data for serum retinol, arguably RBP's most important physiological companion, representing a possible explanation for conflicting results," said Mills. Tanumihardjo added, "Our results further the understanding of the relationship of retinol, RBP, and BMI and suggest that apo-RBP should be evaluated. Retinol:RBP may add new insights and be a better clinical diagnostic for potential insulin resistance than RBP alone." The authors say, "This elevated serum apo-RBP may be adipose-derived and it is unknown whether it is a direct contributor to insulin resistance in obese individuals. Alternatively, apo-RBP from adipose may transport an unidentified ligand that is responsible for mediating insulin signaling." Further research is needed to determine whether apo-RBP is bound to some other compound in circulation. Dr. Steven R. Goodman, Editor-in-Chief of Experimental Biology and Medicine, said "this interesting study, led by Dr. Tanumihardjo, opens the door to the determination of the role of apo-RBP in insulin resistance in obese individuals. This will be an important issue for those working on type 2 diabetes".


Contact: Sherry A. Tanumihardjo
Society for Experimental Biology and Medicine

Related biology news :

1. When accounting for the global nitrogen budget, dont forget fish
2. Fighting Aussie yabbies dont forget a face -- new research by the University of Melbourne
3. Low vitamin D during pregnancy linked to pre-eclampsia
4. Low vitamin D linked to higher risk of hip fracture
5. Vitamin E trials fatally flawed
6. Study shows vitamin C is essential for plant growth
7. Could vitamin D, a key milk nutrient, affect how you age?
8. Vitamin B-12 function may be diminished by excessive folate
9. Jefferson scientists studying the effects of high-dose vitamin C on non-Hodgkin lymphoma patients
10. New way to produce high-vitamin corn could improve nutrition in developing countries
11. Team finds an economical way to boost the vitamin A content of maize
Post Your Comments:
(Date:6/21/2016)... , June 21, 2016 NuData ... the new role of principal product architect and ... the director of customer development. Both will report ... technical officer. The moves reflect NuData,s strategic growth ... response to high customer demand and customer focus ...
(Date:6/9/2016)... 9, 2016  Perkotek an innovation leader in attendance control systems is proud to ... hours, for employers to make sure the right employees are actually signing in, and ... ... ... ...
(Date:6/2/2016)... 2016 The Department of Transport Management ... 44 million US Dollar project, for the , ... Personalization, Enrolment, and IT Infrastructure , to ... and implementation of Identity Management Solutions. Numerous renowned international vendors ... Decatur was selected for the most compliant and ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... June 23, 2016 , ... Supplyframe, the Industry Network for ... Design Lab . Located in Pasadena, Calif., the Design Lab’s mission is to ... are designed, built and brought to market. , The Design Lab is Supplyframe’s ...
(Date:6/23/2016)... ... June 23, 2016 , ... In a new case report published today in ... patient who developed lymphedema after being treated for breast cancer benefitted from an injection ... for dealing with this debilitating, frequent side effect of cancer treatment. , ...
(Date:6/23/2016)... BEACH, Calif. , June 23, 2016  Blueprint ... new biological discoveries to the medical community, has closed ... co-founder Matthew Nunez . "We have ... us with the capital we need to meet our ... will essentially provide us the runway to complete validation ...
(Date:6/23/2016)... 23, 2016 On Wednesday, June 22, ... down 0.22%; the Dow Jones Industrial Average edged 0.27% lower ... 2,085.45, down 0.17%. has initiated coverage on the following ... Therapeutics (NASDAQ: NKTR ), Aralez Pharmaceuticals Inc. (NASDAQ: ... BIND ). Learn more about these stocks by accessing ...
Breaking Biology Technology: