Eicosanoid production and levels of newly characterized eicosanoid-forming enzymes in glomeruli and tubules of rat kidneys

Summary: We examined the production of prostaglandin (P0) E₂, 6-keto PGF_1α and thromboxane (Tx) B₂, the mass of cyclooxygenase (COX) isoenzymes and the activities of phospholipases A₂ and C in glomeruli, cortical tubules and medullary tubules of rat kidneys. Medullary tubules produced significantly greater amounts of PGE₂, 6-keto PGF1α. and TxB2 than glomeruli or cortical tubules. the most abundant eicosanoid in medullary tubules was 6-keto PGF1_α. By contrast, glomeruli and cortical tubules predominantly produced POE₂ (glomeruli > cortical tubules). Levels of COX 1 were markedly greater in medullary tubules than in glomeruli or cortical tubules. Glomeruli had significantly greater amounts of COX 1 than cortical tubules. Detectable amounts of COX 2 were not present in the three preparations. the activity of phospholipase (PL) A₂ against phosphatidyicholine (PC) was significantly greater in tubules (medullary tubules > cortical tubules) than in glomeruli. By contrast, there was a significant increase in the activity of PLA₂ against phosphatidylethanolamine (PE) in glomeruli as compared to tubules (medullary tubules > cortical tubules). the activity of PLC was the Weatest in medullary tubules. Glomeruli had significantly greater activity of PLC than cortical tubules. the order of magnitude for the total activity of the three phospholipases in membranes was medullary tubules> glomeruli> cortical tubules. the total production rate of POE₂, 6-keto PGF1α and TxB₂ was in parallel with the amount of COX 1 and the total activity of membranous phospholipases A₂ and C in the three preparations. In conclusion, there are differences in the production of PGE₂, 6.-keto PGF1α and TxB₂, the ainount of COX 1 and the activities of phospholipases A₂ andC among glomeruli, cortical tubules and medullary tubules of rat kidneys; and the different aspects of COX 1 and phospholipases A₂ and C have a key role in the control of eicosanoid production in the three preparations.     

The Diagnosis of Alcohol and Cannabis Dependence in Cocaine Dependents and Alcohol Dependence in their Families

Genetic research in alcoholism has made major advances in recent decades. Twin, adoption, high-risk and familial studies have demonstrated an inheritance factor in alcoholism. Few studies have demonstrated a genetic predisposition to cocaine and cannabis dependence. Two hundred and sixty-three inpatients were given a structured psychiatric interview retrospectively (180) and prospectively (113) to obtain DSM-III-R diagnosis of cocaine, alcohol and cannabis dependence disorders in the inpatients and of alcohol dependence in family members. Our study reveals a large number of cocaine dependents with a positive family history for alcohol dependence. Approximately 50% of cocaine addicts had at least a first or second degree relative with a diagnosis of alcohol dependence when studied by the family history and study methods. As many as 89% of cocaine dependents diagnosed by DSM-III-R criteria for cocaine dependence qualified for other alcohol and drug dependence diagnoses. Our study finds a high prevalence of alcohol (67% and 89%) and cannabis dependence (51% and 46%) in patients with cocaine dependence. Previous reports regarding alcohol and other drug dependence among cocaine dependents and their families are few and inconclusive. The diagnosis of other drug and alcohol dependence in cocaine dependence and in family members of cocaine dependents has important impact on etiology, prognosis and treatment.     

The expression of mRNA for tumour necrosis factor-α increases in the obstructed kidney of rats soon after unilateral ureteral ligation

Summary: Cytokines, including transforming growth factor (TGF)-β1, contribute to the tubulointerstitial fibrosis of ureteral obstruction. Tumour necrosis factor (TNF)-α, a proinflammatory cytokine produced by multiple cells including macrophages and resident renal cells, has a role in inflammatory cell recruitment in glomerular injury. We measured TNF-α mRNA in the renal cortex of rats at different times after the onset of unilateral ureteral obstruction (UUO) and determined whether angiotensin II (AngII) inhibition or total body irradiation affects the mRNA levels of TNF-α. Rats were killed at 1, 2, 4, 24, 72 and 120h after UUO. Levels of TNF-α mRNA increased significantly in the obstructed kidney at 1h (X 2), 2h (X 2.7), 4h (X 3.6), 24h (X 2.7), 72h (X 1.8) and 120h (X 2.8) after ureteral ligation when compared to the contralateral kidney of the same animals or to control (normal) kidneys. Tumour necrosis factor-α mRNA increased in renal cortical tubules but not in glomeruli. Treatment with enalapril, an angiotensin-converting enzyme (ACE) inhibitor, before and after UUO decreased TNF-α mRNA levels in the obstructed kidney by about 40% at 4h after the onset of UUO, but at 120h there was no difference in TNF-α levels in the obstructed kidney of treated and untreated animals. Total body irradiation, which depletes macrophages in the obstructed kidney, did not prevent the upregulation of TNF-α mRNA expression at 4 h after UUO. Thus, TNF-α may have a role in initiating tubulointerstitial injury in the obstructed kidney. Leucocytes infiltrating the renal interstitium of the obstructed kidney do not appear to contribute to the increased mRNA expression of TNF-α. Angiotensin II may contribute, at least in part, to the early increased expression of TNF-α mRNA in the obstructed kidney.     

The recovery of renal function in rats after release of unilateral ureteral obstruction: the effects of moderate isotonic saline loading

Following 24 h of ureteral obstruction in the rat, renal blood flow and glomerular filtration rate are markedly depressed. The effect of saline loading on post-obstructive glomerular filtration (GFR) was studied in 15 female Sprague-Dawley rats in the awake state, 4 h following the release of 24 h of unilateral ureteral obstruction. Group I (n = 8) received 39 microliters min-1 of 0.9% saline only for 1 h prior to study and Group II (n = 7) received 78 microliters min-1 of 0.9% saline for the whole 4 h prior to study. The Cin and CPAH of the post-obstructed kidney were significantly reduced over control values in both groups. Saline loading (Group II) resulted in an improvement in Cin in the post-obstructed kidney compared with group I (3.22 +/- 0.14 vs. 2.19 +/- 0.14 ml/min/kg BW, P less than 0.001). This was independent of any change in CPAH. In two further groups of rats the saline loading protocol was shown to cause a rise in the excretion of urinary cGMP in the post-obstructed kidney, but not the contralateral control kidney. In addition, administration of exogenous atriopeptin (1-24) to non-saline loaded animals resulted in a qualitatively similar alteration in renal function to saline loading, namely a rise in Cin and an increase in excretion of cGMP by the post-obstructed kidney, and no change in CPAH.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mechanism of the decreased eicosanoid production in vitro in response to angiotensin II in glomeruli of rats with bilateral ureteral obstruction

Summary: Glomeruli isolated from rats with bilateral ureteral obstruction (BUO) of 24 h duration synthesized significantly greater amounts of prostaglandin (PG)E₂, 6-keto PGF_1a, thromboxane (Tx)B₂ and leukotriene (LT)B₄ than glomeruli isolated from sham-operated control (SOC) rats. Glomeruli isolated from SOC rats produced increased amounts of these four eicosanoids compared to basal conditions when 100 nmol/L angiotensin II (AII) was added in vitro to the preparations. However, no significant increases in glomerular eicosanoid production were seen under these conditions in glomeruli of rats with BUO. to examine the mechanims underlying imparied eicosanoid production in glomeruli of rats with BUO exposed to AII in vitro, we measured the activities of phosphatidylethanolamine (PE)-specific phospholipase A₂ (PLA₂), 5-lipoxygenase and the cyclo-oxygenase pathway enzymes including cyclo-oxygenase, PGE₂ isomerase and PGI₂ and Tx synthases under basal conditions and after addition of 100 nmol/L AII in vitro in glomeruli isolated from SOC rats and rats with BUO of 24 h duration. the basal activities of all of these enzymes were significantly greater in glomeruli of rats with BUO compared to SOC rats. In glomeruli of SOC rats, the activities of these enzymes were markedly increased when exposed to 100 nmol/L AII in vitro compared to basal conditions. By contrast, no significant changes in the activities of enzymes involved in eicosanoid formation above baseline were seen in glomeruli of rats with BUO exposed to AII in vitro. the production rates of eicosanoids paralleled the activities of these enzymes under basal and AII-stimulated conditions in glomeruli obtained from SOC rats and rats with BUO. Thus, the lack of increased levels of PGE₂, 6-keto PGF_1a, TxB₂ and LTB₄, when glomeruli of rats with BUO of 24 h duration are exposed to 100 nmol/L AII in vitro, maybe due mainly to either the action of PE-specific PLA₂ or the combined action of PE-specific PLA₂, cyclo-oxygenase pathway enzymes and 5-lipoxygenase set at, or near, maximum levels as a consequence of BUO.