**Chronic Renal Disease and Endocrinology**

302 Basic and Clinical Endocrinology Up-to-Date

Yamaguchi, M. & Gao, Y.H. Inhibitory effect of genistein on bone resorption in tissue culture.

Yamaguchi, M. & Sugimoto, E. stimulatory effect of genistein and daidzein on protein

Yang, J., Liu, J. & De Franco, D.B. Subnuclear trafficking of glucocorticoid receptors in vitro: chromatin recycling and nuclear export. J Cell Biol 1997; 137: 523–538.

synthesis in osteoblastic MC3T3-E1 cells: activation of aminoacyl-t-RNA synthetase.

Biochem Pharmacol. 1998; 55: 71-6.

Mol Cell Biochem 2000; 214: 97–102

**13** 

*Japan* 

**Hormonal Actions and Interactions in** 

Akihiko Saito1, Michihiro Hosojima2 and Hiroyoshi Sato1

*Niigata University Graduate School of Medical and Dental Sciences* 

*1Department of Applied Molecular Medicine* 

*2Division of Clinical Nephrology and Rheumatology* 

**Proximal Tubule Cells Associated with** 

**the Development of Chronic Kidney Disease** 

As the first tubular segment of the kidney between the Bowman's capsule and the loop of Henle, the proximal tubule is exposed to initial glomerular filtrates. Proximal tubule cells (PTCs) have a variety of functions including 1) reabsorption and intracellular processing of glomerular-filtered substances such as proteins, peptides, glucose, amino acids, uric acid, sodium, potassium, phosphate, bicarbonate and water via apical membrane receptors, transporters, and channels; 2) uptake of substances such as protein-bound compounds via basolateral membrane transporters, followed by metabolism or secretion to the urinary space; and 3) synthesis of bioactive substances that are released to peritubular capillaries (Fig. 1).

Normal functions of PTCs (indicated by arrows) include: 1) reabsorption and intracellular processing of glomerular-filtered substances via apical membrane receptors, transporters, and channels; 2) uptake of substances via basolateral membrane transporters followed by metabolism or secretion into the urinary

Impairment of these diverse functions is likely to affect systemic hemodynamic and metabolic homeostasis and can lead to the development of chronic kidney disease (CKD) and cardiovascular disease (CVD) (Saito, Kaseda et al. 2010). In particular, PTC injury occurs

space; and 3) synthesis of bioactive substances that are released to peritubular capillaries.

during the early stages of diabetic nephropathy, a leading cause of CKD.

Fig. 1. Normal functions of proximal tubule cells (PTCs)

**1. Introduction** 
