THE PRESENCE OF GIANT GRANULES IN THE JUXTAGLOMERULAR CELLS OF BEIGE RATS MAY AFFECT PLASMA-RENIN ACTIVITY AND BLOOD-PRESSURE

Chediak-Higashi syndrome (CHS) is an autosomal recessive disorder, cha racterized histopathologically by giant granules in various cells. Sin ce little is known about the juxtaglomerular (JG) cells of CHS, the pr esent study was undertaken as a morphological investigation of the JG cell of Beige rats, which were found to be a new animal model of CHS. In addition, we measured the blood pressure and plasma renin activity. The blood pressure of Beige rats is similar to that of DA rats, the m other strain of Beige rats. However, the plasma renin activity of Beig e rats increases with age, whereas that of DA rats decreases. Morpholo gically, JG cells of Beige rats gave no evidence of hyperplasia and hy pertrophy. The most conspicuous change was a small number of giant JG granules. Ultrastructurally, JG granules of Beige rats were large, irr egular, and varied in size at 2 months of age, but no age-dependent ch anges were detected. These results suggested that giant JG granule for mation slightly increases renin release with age, but does not affect blood pressure. (C) 1994 Academic Press, Inc.