Transport proteins in rats’ renal corpuscle and tubules

Piret Hussar, Toivo Suuroja¹, Ülo Hussar, Tiit Haviko²

Department of Anatomy, University of Tartu, ¹Department of Morphology, Estonian Agricultural University, ²Department of Traumatology and Orthopedics, University of Tartu, Estonia

Key words: renal corpuscle, tubuli nephroni, transepithelial transport proteins.

Summary. The localization of transepithelial transport proteins for glucose and water reabsorption in renal corpuscle and tubules epithelium was observed.

Material and methods. Immunohistochemistry of normal male Wistar rats’ kidney has been performed. Facilitated diffusion glucose transporter GLUT4, Na(+)-dependent glucose co-transporter SGLT1, a cargo transporter TGN38, and water transporter aquaporin-2 (AQP2) were used. Results. An intensive GLUT4 expression in renal proximal tubules and in convoluted segment of distal tubules has been observed. The intensive SGLT1 expression was marked in all renal tubules, and also in the glomerulus of the renal corpuscle. TGN38 was expressed mainly in the S1 of proximal tubules and a bit weaker in the distal tubules. The most intensive AQP2 expression in the proximal tubules and in the thin part of Henle’s loop has been detected. In some cases AQP2 expression in the collecting tubules has been observed. The same tubules nephroni are marked heterogeneously. The distribution of transepithelial transport proteins in different parts of nephroni is also greatly heterogeneous because of weak determination of urinary system.

Conclusion. The comparable transport-proteins distribution with technique of fluorescence immunohistochemistry in rats’ renal corpuscle and tubules was elucidated. Data suggest that expression of glucose and water transepithelial transporter proteins is heterogeneous in all parts of nephron, and, probably, is in accordance with recycling of transport proteins.

Correspondence to Ü. Hussar, Department of Anatomy, University of Tartu, Arhitekti 28, 50407 Tartu, Estonia E-mail: ulo.hussar@ut.ee

Received 10 December 2003, accepted 22 April 2004