Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phospholipase A2 (PLA2) activity is elevated in cardiac microsomal fractions and phospholipids (PL) are much reduced in both the cardiac mitochondria and microsomal fractions from rats subjected to prolonged swimming. Preadministration of coenzyme Q10 (CoQ10 i.v. 30 mg/kg) significantly suppressed these changes. Two groups of 8-week-old male Wistar rats were trained to swim, receiving 30 min of training for 4 days. On the fifth day they were given an intravenous injection of either 30 mg/kg CoQ10 in saline or 1 ml saline. Thirty minutes later they began to swim for 3 hours carrying a weight representing 3% of body weight. On completion of the swim they were sacrified by instantaneous decapitation, and cardiac mitochondria were isolated. Mitochondria were also prepared from saline injected, unexercised control rats. Phosphatidylethanolamine (PE) and phosphatidylcholine (PC) concentrations were measured with HPLC and PLA2 activity was assayed fluorometrically. The mitochondrial concentrations (means +/- SEM, n = 6) of PE and PC were respectively 126 +/- 22 and 140 +/- 22 nmol/mg protein in the exercise-CoQ10 group against 66 +/- 4 and 50 +/- 10 nmol/mg protein in the exercise-saline group. The specific PLA2 activities (expressed as nmol degraded dipyrene phosphorylethanolamine substrate/hr/mg protein) in the microsomes was 0.20 +/- 0.02 in the exercise-CoQ10 group against 0.30 +/- 0.02 in the exercise-saline group. These results suggest CoQ10 has a protective effect against an excessive reduction in mitochondrial membrane phospholipids during prolonged exercise.
 ...
PMID:Suppressive effect of coenzyme Q10 on phospholipase A2 activation in cardiac cells after prolonged swimming. 151 74

Phospholipase A2 (PLA2) activity was found in the sera and synovial fluids (SF) in rheumatoid arthritis (RA) and osteoarthritis (OA). PLA2 activity in RA SF was 6158 +/- 549 (SEM) U/ml (n = 48) and in RA sera 554 +/- 175 U/ml (normal sera-115 +/- 12 U/ml). In OA SF PLA2 activity was 5069 +/- 542 U/ml (n = 28), and in OA sera 268 +/- 55 U/ml. There was no significant difference between SF PLA2 activity in RA and OA. PLA2 activity in SF did not correlate with muramidase (lysozyme), beta-glucuronidase, total protein or white cell count, which were all significantly higher in RA SF than OA. A positive correlation between PLA2 in SF and matched sera was found in both RA and OA. It may be concluded that significant elevation of extracellular PLA2 occurs in both RA and OA, especially in the SF. The fact that high PLA2 did not correlate with other enzymes such as lysozyme and beta-glucuronidase, which are usually high in RA and low in OA SF, may mean that the handling of PLA2 in the joint space is different from other enzymes.
 ...
PMID:Phospholipase A2 activity in sera and synovial fluids in rheumatoid arthritis and osteoarthritis. Its possible role as a proinflammatory enzyme. 403

Previous studies have shown that stimulus-secretion coupling for the release of insulin from the pancreatic islet is potentiated by phospholipase A2 activity. Several biochemically distinct phospholipase A2 activities have been described in the islet. A recently identified cytosolic high molecular weight phospholipase A2, which requires Ca2+ for association with cellular membranes but not for catalytic activity can be activated in a protein kinase C-dependent manner in other cell-types. We determined its phosphorylation and activation in response to phorbol ester and glucose in cultured islet cells from neonatal rats. Islet cell monolayers were labelled to equilibrium with [32P]orthophosphate. Following stimulation cytosolic phospholipase A2 was immunoprecipitated and, after electrophoretic separation and transfer to nitrocellulose membrane, 32P-labelled protein was detected by autoradiography. Phospholipase A2 activity of islet cell cytosol was determined by hydrolysis of exogenous I-stearyl- 2[14C]arachidonyl phosphatidylcholine substrate. It could be shown that phosphorylation of immunoprecipitated phospholipase A2 was augmented by prolonged glucose exposure (> 1 hr) in a protein kinase C-dependent manner. Phosphorylation occurred concomitant with a glucose-induced increase in total cellular phospholipase A2 activity (177 +/- 3 nmol substrate hydrolysed/mg protein at glucose 5.6 mM vs 267 +/- 32 (SEM, n = 4) at glucose 25 mM, P < 0.05). Both acute protein kinase C (459 +/- 71) and glucose-activated phospholipase A2 activities were reduced in the presence of a specific arachidonic acid analogue inhibitor of cytosolic phospholipase A2 (to 231 +/- 10 and 161 +/- 17, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Glucose-induced phosphorylation and activation of a high molecular weight cytosolic phospholipase A2 in neonatal rat pancreatic islets. 758 5

Phospholipase A2 values increase in serum in various inflammatory states, infections, and postoperatively in surgical patients. Several organs, including the liver and spleen have been suggested as sources of circulating phospholipase A2. The purpose of the present work was to examine the possible role of the spleen as a source of elevated serum concentrations of phospholipase A2 after surgery. Pre- and postoperative serum samples of patients undergoing splenectomy were studied for group I phospholipase A2, group II phospholipase A2, and C-reactive protein mass concentrations and catalytic activity concentration of phospholipase A2. The catalytic activity concentration of phospholipase A2 and the mass concentrations of group II phospholipase A2 and C-reactive protein increased postoperatively (8.08 +/- 1.40 U/l vs. 3.96 +/- 0.89 U/l (mean +/- SEM) for phospholipase A2 catalytic concentration (p < 0.03), and 154.8 +/- 32.1 micrograms/l vs. 47.5 +/- 14.7 micrograms/l (mean +/- SEM) for group II phospholipase A2 mass concentration (p < 0.02, n = 7). The mass concentration of group I phospholipase A2 remained unchanged. The catalytic concentration of phospholipase A2 correlated well with the mass concentration of group II phospholipase A2 (p < 0.001, r = 0.846, n = 43). The concentration of C-reactive protein correlated well with the mass concentration of group II phospholipase A2 (p < 0.001, r = 0.566, n = 43) in serum. The results indicate that group II phospholipase A2 is released into the circulation after splenectomy, and the spleen seems not to be the source of circulating group II phospholipase A2.
 ...
PMID:Serum phospholipase A2 in patients after splenectomy. 879 Sep 77

Phospholipase A2 has been suggested to be involved in the pathogenesis and pathophysiology of acute pancreatitis. We determined phospholipase A2 and amylase activities in duodenal juice collected during a secretin test from 30 consecutive patients who were suspected to have chronic pancreatitis or biliary disease. The patients underwent endoscopic retrograde cholangiopancreatography (ERCP) the following day. In the 8 patients with ERCP findings of advanced chronic pancreatitis, the mean outputs of phospholipase A2, amylase, and bicarbonate were reduced by 74%, 72%, and 60% compared to the respective values in the 13 (control) patients without a diagnosis of any pancreatic disorder or jaundice. In the 3 patients with recurrent pancreatitis but normal ERCP findings and in the 6 patients with jaundice the output values were not significantly reduced compared to those in the patients without any pancreatic disorder or jaundice. The outputs of amylase and phospholipase A2 were not significantly interrelated, whereas the outputs of phospholipase A2 and bicarbonate correlated well. Receiver characteristic (ROC) curves confirmed the high specificity and sensitivity of phospholipase A2 or bicarbonate output in patients with ERCP findings of advanced chronic pancreatitis compared to those with no changes in pancreatic ducts, with similar probability values of 0.880 +/- 0.111 (SEM), compared to the respective lower value of amylase, 0.676 +/- 0.118. Phospholipase A2 and bicarbonate output proved of equal value as markers of chronic pancreatitis and were superior to amylase output in the secretin test.
 ...
PMID:Duodenal secretion of phospholipase A2, amylase, and bicarbonate in chronic pancreatitis. 960 59

Membrane components, such as phospholipids, play an important role in the regulation of prostatic 5alpha-reductase activity. To describe in more detail the impact of such regulation on 5alpha-reductase activity, epithelial and stromal cell homogenates of human BPH were treated with phospholipases to specifically alter the structure of cellular phospholipid components. Phospholipase A(2) (PLA(2)) was used to alter the structure of the nonpolar, hydrophobic region of the membrane bilayer. Various types of phospholipase C (PLC) affect the polar, hydrophilic region of phospholipids. In epithelium and stroma, 5alpha-reductase activity was dose-dependently inhibited by PLA(2) and PLC type III. In epithelium and stroma, the mean IC(50) values of PLA(2) were 9.4 +/- 1.1 and 13.9 +/- 2.6 [U/mg protein +/- SEM], respectively. The mean IC(50) values of PLC type III in epithelium and stroma were 4.5 +/- 1.2 and 1.7 +/- 0.2 [U/mg protein +/- SEM], respectively. In epithelium as well as in stroma, 5alpha-reductase activity was more greatly inhibited by PLC type III than by PLA(2). Both in epithelium and stroma, PLA(2) significantly decreased the V(max) of 5alpha-reductase whereas its K(m) remained unaffected. A similar decrease in V(max) was found with PLC type III in epithelium and stroma. Furthermore, the K(m) of epithelial 5alpha-reductase increased significantly following the addition of PLC type III. The two phospholipases, with their specific substrate affinities and sites of hydrolysis, exhibited significantly different effects on 5alpha-reductase, indicating that 5alpha-reductase activity is not unspecifically affected by modification of the hydrophilic milieu. Rather, 5alpha-reductase activity is specifically modulated by various phospholipids and/or phospholipolysis mediated degradation products. These findings suggest that the structural composition of the lipid environment plays a fundamental role in the post-translational regulation of 5alpha-reductase activity in the epithelium and stroma of human BPH. Thus, changes in membrane phospholipid content seem to be instrumental in the expression of DHT-dependent processes.
 ...
PMID:In vitro modulation of steroid 5alpha-reductase activity by phospholipases in epithelium and stroma of human benign prostatic hyperplasia. 1118 41