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S Klahr

Publications and source records attributed to S Klahr.

At least 91 records · Page 5Linked to original sources
PubMed1993

Bilateral ureteral obstruction alters levels of the G-protein subunits G alpha s and G alpha q/11.

To evaluate the effects of bilateral ureteral obstruction (BUO) on the levels of G-protein subunits in glomeruli, we examined the types and amounts of G-protein subunits in glomerular membranes from sham-operated control (SOC) rats and rats with BUO of 24 hours duration utilizing bacterial toxin-catalyzed ADP-ribosylation and specific antibodies. ADP-ribosylation catalyzed by cholera or pertussis toxin demonstrated the presence of Gs and Gi proteins in glomerular membranes. Immunoblots further revealed the existence of two types of G alpha s (45 and 52 kDa), as well as G alpha i2 (40 kDa), G alpha i3 (41 kDa), G alpha q/11 (42 kDa) and G beta (35 to 36 kDa) in glomerular membranes. The predominant subspecies of G alpha s was the 52 kDa protein. Detectable amounts of G alpha o were not found in glomerular membranes. Moreover, G-protein subunits were not detected in cytosolic extracts of glomeruli. Both forms of G alpha s and G alpha q/11 were significantly reduced in glomerular membranes from rats with BUO when compared to SOC rats. No significant difference in total G alpha i, G alpha i2 and G alpha i3 and G beta content was observed between the two groups of rats. In vivo pretreatment of rats with simultaneous administration of the angiotensin-converting enzyme inhibitor, enalaprilat, and the thromboxane synthase inhibitor, OKY-046, maintained the amount of G alpha s and G alpha q/11 in rats with BUO at the levels seen in SOC rats. The two drugs did not affect the amounts of G-protein subunits in glomerular membranes of SOC rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate Ribose↗
PubMed1993

Protein intake affects levels of G-protein subunits G alpha i2, G alpha i3, and G beta in rat glomerular membranes.

Using toxin-catalyzed ADP-ribosylation and specific immunoblots we examined whether the mass of G-protein subunits, G alpha s, G alpha i (includes G alpha i2, G alpha i3, and G alpha 0) and G alpha beta, in glomerular membranes was altered by dietary protein intake. ADP-ribosylation catalyzed by cholera toxin (CT) or pertussis toxin (PT) detected significant amounts of G alpha s or G alpha i in glomerular membranes from rats fed a low (6% casein) or a high (40% casein) protein diet. There was no significant difference in G alpha s content between glomerular membranes from low or high protein-fed rats. However, the amounts of G alpha i were significantly lower in glomerular membranes from rats fed a high protein diet when compared to glomerular membranes from rats fed a low protein diet. Two isoforms of immunoreactive G alpha s, 45 and 52 kDa proteins, were detected in glomerular membranes. The predominant isoform of G alpha s was a 52 kDa protein. As with ADP-ribosylation, immunoblots showed no significant difference in G alpha s content between glomerular membranes obtained from the two diet groups of rats. Also, immunoreactive G alpha i2, G alpha i3 and G beta were present in glomerular membranes. The mass of G alpha i2 and G alpha i3 was significantly lower in glomerular membranes of rats fed a high protein diet than in those of rats fed a low-protein diet. The decreased mass of total G alpha i, that is G alpha i2 and G alpha i3, was comparable to that seen with PT-catalyzed ADP-ribosylation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate Ribose↗
PubMed1993

Increased expression of TGF-beta 1 mRNA in the obstructed kidney of rats with unilateral ureteral ligation.

Renal interstitial fibrosis is a common consequence of chronic ureteral obstruction. While several cytokines may initiate fibrogenesis, TGF-beta is considered to be a major stimulating factor. It has been reported that TGF-beta 1 regulates extracellular matrix (ECM) synthesis, that thromboxane (Tx) stimulates ECM protein synthesis, and that angiotensin II (Ang II) increases expression of TGF-beta 1 mRNA in rat aortic smooth muscle cells. Therefore, we measured TGF-beta 1 mRNA expression by reverse transcription coupled with polymerase chain reaction in renal cortex of rats with unilateral ureteral obstruction (UUO) to determine whether Ang II and/or Tx stimulates increases in TGF-beta 1 mRNA. TGF-beta 1 mRNA levels in contralateral kidneys of rats with UUO did not change significantly during 14 days of obstruction, while in the obstructed kidney TGF-beta 1 mRNA levels were increased significantly after three days as compared to the control (unoperated rats) kidneys. The increase in TGF-beta 1 mRNA expression in the obstructed kidney cortex was found in tubular cells rather than glomeruli. OKY-046, an inhibitor of thromboxane synthase, did not affect the changes in TGF-beta 1 mRNA in the obstructed kidney. Enalapril, an angiotensin I converting enzyme inhibitor, significantly blunted but did not completely abrogate the increase in TGF-beta 1 mRNA. These data suggest that in obstruction TGF-beta 1 is increased at the transcriptional level and thus may play a role in initiating fibrogenesis in obstructive nephropathy. The effect of thromboxane on extracellular matrix synthesis does not appear to be mediated by TGF-beta 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Effects of unilateral or bilateral release of bilateral ureteral obstruction on renal function in rat.

Renal function was examined after unilateral release, bilateral release or unilateral release and contralateral nephrectomy in three groups of rats following 24 h of bilateral ureteral obstruction (BUO). Excretion of water, sodium and urea was significantly greater in rats with unilateral release of BUO than in a single kidney of rats with bilateral release of BUO, in spite of similar levels of glomerular filtration rate (GFR) and effective renal plasma flow. Rats with unilateral release of obstruction and contralateral nephrectomy had a significantly lower GFR than the other two groups. These rats also responded with greater increases in fractional sodium and water excretion to the administration of exogenous atrial peptide. The results demonstrate a marked compensatory increase in sodium and water excretion in rats with unilateral release of the obstruction which serves to maintain homeostasis of fluid and salt. They also suggest a possible influence of the continuously obstructed kidney on the function of the postreleased kidney. The results also provide experimental support for a greater recovery of renal excretory function after bilateral release of obstruction.

Animals↗
PubMed1993

L-arginine administration prevents glomerular hyperfiltration and decreases proteinuria in diabetic rats.

The effect(s) of L-arginine administration on the renal function of rats with untreated diabetes mellitus was examined. Rats received streptozotocin (N = 11) or vehicle (N = 12): Group 1 (normal rats, N = 6) drank tap water; Group 2 (normal rats, N = 6) drank tap water containing 1% L-arginine; Group 3 (diabetic rats, N = 5) drank tap water; and Group 4 (diabetic rats, N = 6) drank tap water with 1% L-arginine. Rats were fed a standard rat chow diet (22.8% protein, 142% L-arginine) with free access to food and water for 14 wk. Diabetic rats gained less weight, had significantly lower plasma levels of albumin and L-arginine, and had greater values for 24-h urine volumes and urine excretion of glucose, protein, urea, creatinine, nitrate, and nitrite than control rats. Diabetic rats given L-arginine (Group 4) had significantly lower protein and cGMP excretion in the urine than did rats of Group 3. The administration of L-arginine did not affect the plasma levels of glucose or L-arginine in Groups 2 or 4 compared with those of their respective controls. Group 3 had significantly higher values for GFR than did the other three groups of rats, but values for effective RPF, mean arterial pressure, hematocrit, and renal vascular resistance were not significantly different between Groups 3 and 4. There was no significant difference in glomerular morphology among the four groups of rats as determined by light microscopy, and both groups of diabetic rats exhibited the Armanni-Ebstein lesion in their tubules.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Increases in glomerular eicosanoid production in rats with bilateral ureteral obstruction are mediated by enhanced enzyme activities of both the cyclooxygenase and 5-lipoxygenase pathways.

Glomeruli isolated from rats with bilateral ureteral obstruction (BUO) of 24 hr duration produced significantly greater amounts of prostaglandin (PG) E2, 6-keto-PGF1 alpha, thromboxane B2, and leukotriene B4 than glomeruli isolated from sham-operated control (SOC) rats. To examine the mechanisms underlying the greater production of eicosanoids by glomeruli isolated from rats with BUO, we measured the activities of enzymes related to eicosanoid formation such as cyclooxygenase, 5-lipoxygenase, PGE2 isomerase, and PGI2 and thromboxane synthase in glomeruli isolated from SOC rats and rats with BUO. Glomeruli isolated from rats with BUO had a significantly increased activity of cyclooxygenase with de novo synthesis of this enzyme and a markedly augmented activities of PGE2 isomerase and both PGI2 and thromboxane synthases relative to glomeruli isolated from SOC rats. Similarly, the activity of membrane-bound 5-lipoxygenase, the active location of this enzyme, was significantly greater in glomeruli isolated from rats with BUO than in glomeruli isolated from SOC rats. Thus, BUO of 24 hr duration enhances the glomerular production of eicosanoids via the activation of enzymes in both the cyclooxygenase and 5-lipoxygenase pathways.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Role of glomerular eicosanoid production in the obstructed kidney.

The regional production of prostaglandin E2 and thromboxane B2 was investigated in the kidney with unilateral or bilateral ureteral obstruction for 24 hours in rats. The production of these eicosanoids was highest in the inner medulla both with or without ureteral obstruction, although the production rate by the tubules was relatively low in the obstructed kidney compared to the sham-operated control. A greater production of these vasoactive compounds was noted by glomeruli from the kidneys with unilateral or bilateral obstruction and the contralateral kidney with unilateral obstruction. Glomeruli obtained from the kidney with unilateral obstruction produced more thromboxane B2 than the kidney with bilateral obstruction, and the resultant TxB2/PGE2 ratio was higher in the unilaterally obstructed kidney. This difference in the glomerular thromboxane B2 production may be responsible for the haemodynamic changes between unilateral and bilateral ureteral obstructions. An increased prostaglandin E2 production by glomeruli from the contralateral kidney with unilateral obstruction may contribute to a compensatory response.

Animals↗
PubMed1992

Dietary supplementation with L-arginine ameliorates the progression of renal disease in rats with subtotal nephrectomy.

We studied the effect of dietary supplementation with L-arginine for 6 weeks on the progression of renal disease in female Sprague-Dawley rats subjected to sham-operation (groups 1 and 2) or surgical ablation of 85% to 90% of the total renal mass (groups 3 and 4). All rats were fed a standard rat chow containing 22.8% protein. Rats in groups 1 (n = 5) and 3 (n = 9) served as controls and drank tap water ad libitum. Rats in groups 2 (n = 6) and 4 (n = 6) drank tap water supplemented with 1% L-arginine. Rats in groups 1 and 2 had similar values for glomerular and tubular function and serum chemistries 6 weeks after sham-operation. Sham-operated rats given L-arginine had significantly greater urine urea excretion than similar rats drinking tap water. Rats with subtotal nephrectomy (groups 3 and 4) had a significantly higher blood pressure, greater proteinuria, and a significantly lower plasma albumin than sham-operated rats (groups 1 and 2). Rats with remnant kidneys given 1% L-arginine (group 4) had significantly greater values for glomerular filtration rate (GFR) and P-amino hippurate (PAH) clearance than similar rats given tap water (group 3), despite comparable levels of systemic blood pressure, hematocrit, body weight, plasma chemistries, including L-arginine, and urine chemistries, except urea excretion. The remnant kidney of rats given L-arginine (group 4) had a greater number of normal or minimally abnormal glomeruli and fewer interstitial changes than that of rats given tap water (group 3).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Role of the 5-lipooxygenase pathway in obstructive nephropathy.

Leukotrienes are products of the 5-lipooxygenase pathway of arachidonic acid metabolism that possess potent inflammatory properties. We examined the potential role of this pathway in the decrease in glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) observed in rats after unilateral release of bilateral ureteral obstruction (BUO) of 24 hours duration. Isolated glomeruli from rats with BUO produced significantly greater amounts of leukotriene B4 (LTB4) than glomeruli from sham-operated rats (SOR; P less than 0.0001). Glomeruli from rats with BUO given MK886, an inhibitor of the 5-lipooxygenase enzyme, or from rats with BUO subjected to both total body irradiation to prevent the leukocyte infiltration of the kidney and also given MK886 prior to obstruction, produced amounts of LTB4 not significantly different from those in glomeruli of SOR. Glomeruli from rats with BUO that had only total body irradiation prior to obstruction produced significantly less LTB4 than glomeruli from untreated BUO rats, but LTB4 production was still significantly greater than in glomeruli from SOR. There were no significant differences in GFR among SOR, SOR given MK886, and SOR subjected to total body irradiation. However, SOR given MK886 had significantly higher ERPF and lower renal vascular resistance (RVR) than SOR not pretreated with the lipooxygenase inhibitor. Rats with BUO given MK886, or subjected to total body irradiation, or both, prior to obstruction had significantly greater GFR and ERPF values and lower RVR than untreated BUO rats. Glomeruli from rats with BUO which were not pretreated had three times the leukocytes of glomeruli from SOR. This leukocyte infiltrate was composed of macrophages (about 55%) and neutrophils (about 45%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Protein increases glomerular eicosanoid production and activity of related enzymes.

We examined the in vitro production of PGE2, 6-keto PGF1 alpha and TxB2 by isolated glomeruli from rats fed a low (6% casein) or a high (40% casein) protein diet for approximately eight weeks. Glomeruli from high protein-fed rats produced significantly greater amounts of PGE2, 6-keto PGF1 alpha and TxB2 under basal conditions and in response to the addition of 100 nM angiotensin II (Ang II) than glomeruli from low protein-fed rats. To elucidate the mechanisms by which greater protein intake enhanced the glomerular production of eicosanoids, we explored phospholipase (A2 and C) and cyclooxygenase activity in glomeruli isolated from low- or high-protein fed rats. PE-specific PLA2 activities were significantly increased in glomeruli from rats fed a high protein diet when compared to a low protein diet. On the other hand, PC-specific PLA2 activities were significantly decreased in glomeruli from rats fed a high protein diet. No significant difference in PIP2-PLC activities was detected between glomeruli of the two dietary groups. The cyclooxygenase content and activity was significantly greater in glomeruli from rats fed a high protein diet than in glomeruli from rats fed a low protein diet. Glomeruli of rats fed a 50/50 mixture of the diets (23% casein) had amounts and activity of cyclooxygenase and activities of PE-specific PLA2 intermediate between those of high and low protein-fed animals. In conclusion, increased synthesis of eicosanoids by glomeruli from rats fed a high protein diet may be mediated by increases in the amount and activity of cyclooxygenase coupled with enhanced activity of PE-specific PLA2.

Angiotensin II↗
PubMed1992

G-protein stimulation inhibits amiloride-sensitive Na/H exchange independently of cyclic AMP.

G-proteins are heterotrimeric proteins involved in many transmembrane signaling events. Both the renal basolateral membrane and the renal brush border membrane contain large quantities of these proteins. G-proteins appear related to hormonal signaling in the basolateral membrane and presumably affect ion gating in the brush border. We investigated the influence of G-proteins on the amiloride-sensitive Na/H exchanger, the activity of which is regulated at least in part by cAMP-dependent protein kinase, by measuring the amiloride-sensitive component of [22Na+] uptake in rat renal brush border membrane vesicles (BBMV) in the presence of a pH gradient. Incubation of vesicles with AlF4- (10 microM Al3+, 10 mM F-) resulted in significant inhibition of amiloride-sensitive [22Na+] uptake at both 20 seconds and 5 minutes of incubation. Incorporation of GTP gamma S into BBMV by transient hypotonic lysis also resulted in significantly reduced amiloride-sensitive [22Na+] uptake compared to controls at both time points. This inhibition could be reversed by GDP beta S. Similar lysis in the presence of 10 microM GDP beta S alone had no significant effect. When Na(+)-dependent [14C]-D-glucose uptake into BBMV was studied no significant effect of these G-protein modulating agents was observed. Adenylate cyclase activity could not be stimulated in these BBMV preparations using standard techniques. Furthermore, cAMP-dependent protein kinase activity, strongly stimulated in these BBMV by exogenously added cAMP, was not stimulated by 10 microM GTP gamma S alone. These findings suggest that the amiloride-sensitive Na/H exchanger can be regulated by G-proteins independently of adenylate cyclase and cAMP-dependent protein kinase.

Adenylyl Cyclases↗
PubMed1992

Renal function after release of ureteral obstruction: role of endothelin and the renal artery endothelium.

Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) are decreased and mean arterial pressure (MAP) is increased after unilateral release of bilateral ureteral obstruction (BUO). An imbalance between vasoconstrictor and vasodilator substances may explain the hemodynamic alterations seen in this setting. The present study examines the role of endothelin-1 in such alterations. Rats with BUO (N = 10) had significantly lower GFR and ERPF (ml/min/kg body wt) than sham-operated rats (SOR, N = 9) (1.40 +/- 0.14 vs. 6.20 +/- 0.38 and 5.12 +/- 0.68 vs. 20.2 +/- 2.20, respectively) and significantly higher MAP (mm Hg) than SOR (154.9 +/- 3.2 vs. 120.6 +/- 1.7). Rats with BUO given a specific antiendothelin antibody (N = 8) had significantly higher GFR (2.10 +/- 0.12) and ERPF (7.46 +/- 0.95) than BUO control rats, but there were no significant changes in MAP (159.5 +/- 5.8). In SOR (N = 6), mechanical denudation of the main renal artery endothelium did not significantly affect renal function when compared to renal function in control SOR. However, the same maneuver significantly lowered GFR (0.64 +/- 0.17) and ERPF (1.67 +/- 0.36) in BUO rats (N = 5) when compared to BUO control rats. We conclude that: (1) endothelin-1 has a significant vasoconstrictor role in rats with BUO of 24 hours duration and accounts for a portion of the decrease in glomerular filtration rate seen in rats after unilateral release of bilateral ureteral obstruction, and (2) in the BUO setting, the net role of the renal artery endothelium is vasodilatory.

Animals↗
PubMed1992

EDRF role in renal function and blood pressure of normal rats and rats with obstructive uropathy.

There is a decrease in glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) and an increase in mean arterial pressure (MAP) and renal vascular resistance (RVR) after release of bilateral ureteral obstruction (BUO) of 24 hours duration. The present studies examine the role of endothelium-derived relaxing factor (EDRF) in the renal hemodynamics of sham-operated rats (SOR) and rats in which BUO of 24 hours duration was unilaterally released. In both groups of rats, renal function and blood pressure were measured in the awake state under basal conditions and after administration of L-arginine (L-arg), the substrate for EDRF synthesis, followed by NwNAME, an L-arg antagonist, or after administration of NwNAME followed by L-arg. Administration of L-arg alone to SOR did not affect renal function, MAP or RVR. In SOR given L-arg and then NwNAME, there was significantly decreased GFR and ERPF and increased MAP and RVR. When NwNAME was given initially, similar changes were obtained, and these were reversed by the administration of L-arg. Rats given L-arginine immediately after unilateral release of BUO of 24 hours duration had significantly greater GFR and ERPF values and lower MAP and RVR than temporal controls. NwNAME given to BUO rats decreased renal function further and increased MAP and RVR. We found a dose-dependent increase in GFR and ERPF and a dose-dependent decrease in MAP and RVR in both SOR and rats with BUO given increasing amounts of L-arg. There was also a dose-dependent decrease in GFR and ERPF and an increase in MAP and RVR in SOR and rats with BUO given increasing amounts of NwNAME or NGNMA, the two different antagonists of L-arg. In another set of experiments, SOR and rats with BUO were given L-arg preoperatively (that is, 24 hr prior to study). Both groups of rats had significantly higher GFR and ERPF values and lower MAP and RVR than control rats. Sham-operated rats given NwNAME 24 hours prior to study had significantly lower GFR and ERPF and higher MAP and RVR than untreated rats. Rats with BUO given NwNAME prior to obstruction had no measurable renal function and had significantly higher values for MAP after release of obstruction. These studies confirm the role of L-arg administration, and presumably EDRF, in the regulation of MAP and renal function in sham-operated rats. The results of this study also suggest decreased availability of arginine for EDRF synthesis in rats with BUO.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Cytochrome P-450 pathway in renal function of normal rats and rats with bilateral ureteral obstruction.

Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) are decreased and mean arterial pressure (MAP) and renal vascular resistance (RVR) are increased after unilateral release of bilateral ureteral obstruction (BUO) of 24 hr duration. An imbalance between vasoconstrictor and vasodilator substances may explain these hemodynamic changes. We examined the role of the cytochrome P-450 pathway in this setting. After unilateral release of BUO, GFR and ERPF (ml/min/kg body wt) were significantly lower in these rats than in sham-operated rats (SOR) 1.14 +/- 0.09 vs 6.7 +/- 0.5 and 3.09 +/- 0.2 vs 23.5 +/- 3.4, respectively). BUO rats had significantly higher MAP (mm Hg) and RVR (mm Hg/ml/min/kg body wt) than SOR (155 +/- 5 vs 120 +/- 1 and 29.1 +/- 1.7 vs 3.2 +/- 0.4, respectively). SOR given 3-methylcholanthrene and beta-naphthoflavone to induce the cytochrome P-450 system had no significant changes in renal function, RVR, or MAP. SOR given ketoconazole to inhibit the cytochrome P-450 system had significantly lower GFR (4.8 +/- 0.5) than temporal control rats without significant changes in ERPF (21.2 +/- 4.6), MAP (127 +/- 6), or RVR (4.2 +/- 0.9). Rats with BUO given ketoconazole had lower but not significantly different GFR (0.84 +/- .1) and ERPF (2.61 +/- .4) than BUO controls. Values for MAP did not differ in BUO rats given ketoconazole versus BUO temporal controls. BUO rats given 3-methylcholanthrene and beta-naphthoflavone had significantly higher GFR and ERPF (2.01 +/- 0.24 and 6.66 +/- 1.36, respectively) and significantly lower RVR (14.7 +/- 3.9) than control rats with BUO; MAP was unchanged. Microsomal preparations from indomethacin-treated isolated kidneys obtained from BUO rats when compared with preparations obtained from SOR had significantly less activity of the P-450 cytochrome-dependent omega/omega-1 hydroxylase (103 +/- 6 vs 130 +/- 7 pmol hydroxyeicosatetraenoic acids produced per mg of protein/min, P < 0.02) and the P-450 cytochrome-dependent epoxygenase (11 +/- 0.3 vs 30 +/- 4 pmol lipoxyeicosatrienoic acids produced per mg of protein/min, P < 0.04). Indomethacin-treated microsomes prepared from kidneys of BUO rats converted significantly less 14C-arachidonic acid through the P-450-dependent hydroxylases (13.5 +/- 0.8 vs 17.0 +/- 0.1% of 14C-arachidonic acid converted to 19- and 20-hydroxyeicosatetraenoic acids, P < 0.02), and significantly less through the epoxygenases (1.4 +/- 0.4 vs. 3.8 +/- 0.5% of 14C-arachidonic acid converted to epoxyeicosatrienoic acids).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Subdiaphragmatic vagotomy in rats induces systemic hypertension and sodium retention.

We examined the acute effects of bilateral subdiaphragmatic vagotomy (BSV) on blood pressure and renal function in female Sprague-Dawley rats. Mean arterial pressure was greater (p < 0.0001) in rats with BSV than in sham-operated rats (SOR). Rats with BSV had a significantly lower effective renal plasma flow (p < 0.01), total sodium excretion (p < 0.005), fractional sodium excretion (p < 0.01), urine flow (p < 0.01), and fractional excretion of water (p < 0.02) than SOR. The glomerular filtration rate was not significantly different between the 2 groups of rats. Plasma potassium was greater in rats with BSV than in SOR (p < 0.02). Pretreatment with an inhibitor of the angiotensin-converting enzyme prevented the above changes in rats with BSV. Changes in renal function and mean arterial pressure could not be attributed to antidiuretic hormone since plasma levels of antidiuretic hormone were lower in rats with BSV than in SOR (p < 0.002). In addition, the activity of the sympathetic system was decreased in rats with BSV, as suggested by the lower plasma levels of epinephrine (p < 0.003) and norepinephrine (p < 0.02) and the significantly lower renal tissue concentrations of norepinephrine (p < 0.03). No significant changes in renal tissue concentrations of acetylcholine or choline, its precursor, were observed in BSV rats when compared to SOR, suggesting a lack of renal parasympathetic innervation. Plasma renin activity was lower in rats with BSV (p < 0.02) than in SOR, but this effect was blunted in rats given an angiotensin-converting enzyme inhibitor prior to BSV.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1992

Effects of dietary protein on eicosanoid production and on the activity of related enzymes in glomeruli and tubules.

Glomeruli obtained from rats fed a high-protein diet for 8 weeks produce increased amounts of eicosanoids due to greater activity of both PE-specific phospholipase A2 and cyclooxygenase. Eicosanoid synthesis in response to angiotensin II is also greater in glomeruli from rats fed a high-protein diet when compared to rats fed a low-protein diet. There was also increased synthesis of eicosanoids in medullary/papillary tubules but not in proximal cortical tubules of rats fed a high-protein diet. This appears to be due to increased activity of PC-specific phospholipase A2 and cyclooxygenase in medullary/papillary tubules.

Animals↗