Home | Orthoiodosupplementation | Body | Disease | Special | Overviews

Special Topics

Physiology

Transporters

NIS

• Abraham

• Ajjan, Kilbane, Weetman

• Carrasco

• Colorado SU

• Costagliola

• Elisei

• Endo

• Ferreira

• Filetti

• Fujiwara

• Furlanetto

• Gene Reports

• Heufelder

• Josefsson

• Jhiang

• Kim, Chung

• Kogai

• Kotani

• Lim, Moon

• Mitchell

• Mitrofanova

• Pekary

• Perron

• Riesco-Eizaguirre

• Rhoden

• Schlumberger

• Schmitt

• Smyth

• Spitzweg

• Suzuki

• Tazebay

• Tonacchera

• Upadhyay

• Van Sande

• Venkataraman

• Yoshida, Kosugi

• Wapnir

• Wolff

VAN SANDE

Anion selectivity by the sodium iodide symporter.

Van Sande J, Massart C, Beauwens R, Schoutens A, Costagliola S, Dumont JE, Wolff J.

Endocrinology. 2003 Jan;144(1):247-52.

"The iodide transporter of the thyroid (NIS) has been cloned by the group of Carrasco. The NIS-mediated transport was studied by electrophysiological methods in NIS-expressing Xenopus oocytes. Using this method, the anion selectivity of NIS was different from that previously reported for thyroid cells, whereas perchlorate and perrhenate were found not transported. In this study we compared the properties of human NIS, stably transfected in COS-7 cells to those of the transport in a thyroid cell line, the FRTL5 cells, by measuring the transport directly. We measured the uptake of (125)I(-), (186)ReO(4)(-), and (99m)TcO(4)(-) and studied the effect on it of known competing anions, i.e. ClO(4)(-), SCN(-), ClO(3)(-), ReO(4)(-), and Br(-). We conclude that the properties of the NIS transporter account by themselves for the properties of the thyroid iodide transporter as described previously in thyroid slices. The order of affinity was:

ClO(4)(-) > ReO(4)(-) > I(-) >/= SCN(-) > ClO(3)(-) > Br(-). NIS is also inhibited by dysidenin (as in dog thyroid)."

The Na+-I- cotransporter of the thyroid: characterisation of new inhibitors.

Vroye L, Beauwens R, Van Sande J, Daloze D, Braekman JC, Golstein PE.

Pflugers Arch. 1998 Jan;435(2):259-66.

[abstract only]

"New inhibitors of the Na+-I- cotransporter of the thyroid in bovine thyroid slices and in bovine plasma membrane vesicles have been investigated. They include: (1) econazole; (2) 5-(N,N-hexamethylene)amiloride (HMA); and (3) dysidenin. In both systems, the kinetics of iodide transport yielded apparent Km values of 39 and 14 microM respectively. The possible interaction of each of these inhibitors with the iodide site of the Na+-I- cotransporter was tested by performing detailed transport kinetics analysis at varying iodide concentrations and at 150 mM NaCl. Econazole induced a non-competitive inhibition while dysidenin and HMA gave a mixed type of inhibition. The Ki values for dysidenin and econazole, computed from Dixon plots, were 5 and 2 microM respectively while the Ki value for HMA could not be determined. Each inhibition was reversible, indicating the absence of covalent binding of the inhibitor to the Na+-I- cotransporter."
 

More articles by Van Sande, Braekman, Dumont

 Home | Orthoiodosupplementation | Body | Disease | Special Topics | Overviews  

The Iodine Group | Books | Disclaimers | Contact Us | Search  

  Copyright: Zoe, 2006.