Horm Metab Res 2006; 38(4): 279-290
DOI: 10.1055/s-2006-925348
Review
© Georg Thieme Verlag KG Stuttgart · New York

The Role of Plasma-binding Proteins in the Cellular Uptake of Lipophilic Vitamins and Steroids

T.  K.  Andreassen1
  • 1 Department of Medical Biochemistry, University of Aarhus, Denmark
Further Information

Publication History

Received 19 October 2005

Accepted after revision 20 February 2006

Publication Date:
15 May 2006 (online)

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Abstract

Steroid hormones and many other lipophilic compounds are believed to enter cells solely by free diffusion through the plasma membrane. However, recent work using a megalin-deficient mouse model has identified a new endocytic pathway responsible for the delivery of steroids to renal and gonadal tissues. This review describes these new pathways for uptake of 25-hydroxy-vitamin-D3 and the gonadal sex-steroids (17β-estradiol and testosterone) bound to vitamin D-binding protein and sex hormone-binding globulin respectively. Furthermore examples of other lipophilic molecules that enter cells by receptor-mediated pathways will be presented and the receptors responsible for their uptake described.

References

Thomas K. Andreassen

Department of Medical Biochemistry · University of Aarhus

Ole Worms Alle · Bldg 1170 · 8000 Aarhus C · Denmark

Phone: +45(89)422873

Fax: +45(86)131160

Email: tka@biokemi.au.dk