Renal phospholipase C and diglyceride lipase activity in spontaneously hypertensive rats.
Phospholipase C activity and diglyceride lipase activity were studied in the renal cortex and medulla of 10- and 40-week-old stroke-prone spontaneously hypertensive rats (SHRSP) and age-matched normotensive Wistar-Kyoto rats (WKY). Enhanced phospholipase C activity was found in the cortical and medullary cytosol of kidney from SHRSP, and microsomal diglyceride lipase in SHRSP also increased. In SHRSP, phospholipase C and diglyceride lipase activities increased with age, but this increase was not evident in WKY. Phospholipase C had high substrate specificity for phosphatidylinositol in renal cytosol of both WKY and SHRSP. The increased activities were accompanied by prostaglandin E2 synthesis in renal medullary microsomes of 10-week-old SHRSP and were also present in the kidney of 40-week-old SHRSP. Total phospholipid and arachidonic acid contents in kidney were markedly high in the medulla of 10-week-old SHRSP, but these lipids were decreased in 40-week-old SHRSP. These results suggest that phospholipids and arachidonic acid in SHRSP may be genetically high and that the activated phospholipase C and diglyceride lipase hydrolyze phospholipids, providing arachidonic acid for prostaglandin synthesis, which results in a decrease of phospholipids and arachidonic acid in the kidney of 40-week-old SHRSP. These studies demonstrate that a phosphatidylinositol-specific phospholipase C-prostaglandin synthetic system may play an important role in the course of hypertension in SHRSP.
Kawaguchi
H
H
Okamoto
H
H
Saito
H
H
Yasuda
H
H
D000818:Animals; D015232:Dinoprostone; D006973:Hypertension / Q000201:enzymology* / Q000378:metabolism; D007668:Kidney / Q000201:enzymology* / Q000378:metabolism; D007672:Kidney Cortex / Q000201:enzymology / Q000378:metabolism; D007679:Kidney Medulla / Q000201:enzymology / Q000378:metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008297:Male; D011458:Prostaglandins E / Q000096:biosynthesis; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D010738:Type C Phospholipases / Q000378:metabolism*
D011458:Prostaglandins E; D008071:Lipoprotein Lipase; D010738:Type C Phospholipases; D015232:Dinoprostone