An endocytic pathway essential for renal uptake and activation of the steroid 25-(OH) vitamin D-3

Citation
A. Nykjaer et al., An endocytic pathway essential for renal uptake and activation of the steroid 25-(OH) vitamin D-3, CELL, 96(4), 1999, pp. 507-515
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cell & Developmental Biology
Journal title
CELL
ISSN journal
0092-8674 → ACNP
Volume
96
Issue
4
Year of publication
1999
Pages
507 - 515
Database
ISI
SICI code
0092-8674(19990219)96:4<507:AEPEFR>2.0.ZU;2-3
Abstract
Steroid hormones may enter cells by diffusion through the plasma membrane. However, we demonstrate here that some steroid hormones are taken up by rec eptor-mediated endocytosis of steroid-carrier complexes. We show that 25-(O H) vitamin D-3 in complex with its plasma carrier, the vitamin D-binding pr otein, is filtered through the glomerulus and reabsorbed in the proximal tu bules by the endocytic receptor megalin. Endocytosis is required to preserv e 25-(OH) vitamin D-3 and to deliver to the cells the precursor for generat ion of 1,25-(OH)(2) Vitamin D-3, a regulator of the calcium metabolism. Meg alin(-/-) mice are unable to retrieve the steroid from the glomerular filtr ate and develop vitamin D deficiency and bone disease.