The effect caused by the double condition of potassium loading and simultaneous sodium restriction on the glomerular zone of rats. Histochemical and ultrastructural study.

The effect caused by the double condition of potassium loading (K loading) and simultaneous sodium restriction (Na restriction) on the glomerular zone of rats is reported. After 2-week-diet of K loading and simultaneous Na restriction an increase of width of glomerular zone and decreases and micronization of fat granules were seen. Enzymic activity (glucose-6-phosphate dehydrogenase, steroid 3beta-ol-dehydrogenase) was increased. After 3-week-diet of the same condition the width of glomerular zone became 1/4 to 1/5 of the whole cortex. The cells in the glomerular zone demonstrated a trabecular arrangement. Ultrastructurally, hypertrophy of cells became marked and the size of cell was about 1.5 times that of normal cells. Dense body increased in number and became irregular in shape. In the widened cytoplasm, smooth endoplasmic reticulum and Golgi apparatus were well developed with numerous coated vesicles. Changes of mitochondria such as increase in number, transformation into round shape and vesicular cristae were characteristic. The severity of these changes was proportional to the duration of K loading and simultaneous Na restriction. After 8-week-diet the increase of large-sized lipid vacuole and dense body, and intramitochondrial deposition were observed in parallel with the above-mentioned changes. The changes observed in this study appeared earlier and stronger than those in the single-conditioned group of only K loading or Na restriction. The cause of these changes were considered to be a result of accelerated function of the glomerular cells.