Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

30.09.2008
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".

Experimental Biology and Medicine is the journal of the Society of Experimental Biology and Medicine. To learn about the benefits of society membership visit www.sebm.org.

Sherry A. Tanumihardjo | EurekAlert!
Further information:
http://www.nutrisci.wisc.edu
http://www.ebmonline.org
http://www.sebm.org

More articles from Studies and Analyses:

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

nachricht Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>