Mc. Sekar et al., DECREASED CYCLIC INOSITOL PHOSPHOHYDROLASE ACTIVITY IN HAMSTER RENAL TUMORS AND HUMAN RENAL-CELL CARCINOMAS, Biochemical and molecular medicine, 56(2), 1995, pp. 104-107
Cyclic inositol phosphohydrolase (cIPH) (EC 3.1.4.36) hydrolyzes the c
yclic phosphodiester bond of cyclic inositol monophosphate to yield in
ositol l-phosphate. Renal tissue in various species has been shown to
contain the highest activity of this enzyme. Cyclic inositol monophosp
hate, the substrate for this enzyme, has been implicated in the regula
tion of cell density. Thus, we determined whether activity of this enz
yme is modulated in renal tumor. Samples of hamster renal tumors induc
ed by diethylstilbestrol (DES) demonstrated 87% less cIPH activity tha
n control hamster kidney. After 8 days of DES treatment of hamsters, a
28% decrease in the cIPH activity in kidney was observed. Interesting
ly, comparison of the cIPH activity in normal human kidney cortex, med
ulla, and renal cell carcinoma gave the following values (mean +/- SD)
, 10.6 +/- 4.6 (9), 6.7 +/- 4.6 (5), and 1.9 +/- 2.3 (8), respectively
. Our study demonstrates that cIPH activity is reduced in hamster and
human renal tumors. (C) 1995 Academic Press, Inc.