Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


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".

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

Sherry A. Tanumihardjo | EurekAlert!
Further information:

More articles from Studies and Analyses:

nachricht Diagnoses: When Are Several Opinions Better Than One?
19.07.2016 | Max-Planck-Institut für Bildungsforschung

nachricht High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg

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: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Innovative technique for shaping light could solve bandwidth crunch

20.10.2016 | Physics and Astronomy

Finding the lightest superdeformed triaxial atomic nucleus

20.10.2016 | Physics and Astronomy

NASA's MAVEN mission observes ups and downs of water escape from Mars

20.10.2016 | Physics and Astronomy

More VideoLinks >>>