Mapping a sustainable approach: biosynthesis of lactobacilli-silver nanocomposites using whey-based medium for antimicrobial and bioactivity applications.

This study explores a sustainable approach for synthesizing silver nanocomposites (AgNCs) with enhanced antimicrobial and bioactivity using safe Lactobacillus strains and a whey-based medium (WBM). WBM effectively supported the growth of Lactobacillus delbrueckii and Lactobacillus acidophilus, triggering a stress response that led to AgNCs formation. The synthesized AgNCs were characterized using advanced spectroscopic and imaging techniques such as UV‒visible, Fourier transform infrared (FT-IR) spectroscopy, transmission electron (TEM), and scanning electron microscopy with energy dispersive X-ray analysis (SEM-Edx). Lb acidophilus-synthesized AgNCs in WBM (had DLS size average 817.2-974.3 ± PDI = 0.441 nm with an average of metal core size 13.32 ± 3.55 nm) exhibited significant antimicrobial activity against a broad spectrum of pathogens, including bacteria such as Escherichia coli (16.47 ± 2.19 nm), Bacillus cereus (15.31 ± 0.43 nm), Clostridium perfringens (25.95 ± 0.03 mm), Enterococcus faecalis (32.34 ± 0.07 mm), Listeria monocytogenes (23.33 ± 0.05 mm), methicillin-resistant Staphylococcus aureus (MRSA) (13.20 ± 1.76 mm), and filamentous fungi such as Aspergillus brasiliensis (33.46 ± 0.01 mm). In addition, Lb acidophilus-synthesized AgNCs in WBM exhibit remarkable free radical scavenging abilities, suggesting their potential as bioavailable antioxidants. These findings highlight the dual functionality of these biogenic AgNCs, making them promising candidates for applications in both medicine and nutrition.

Modulatory effect of concomitant administration of sitagliptin and vitamin E on inflammatory biomarkers in rats fed with high fat diet: role of adiponectin.

Sitagliptin (SIT) is an antidiabetic used worldwide to ameliorate the hyperglycemia and insulin insensitivity induced dysmetabolism. In this study, we investigated the effect of sitagliptin and vitamin E on metabolic dysfunction in high-fat diet (HFD) fed rats. Sixty-four male rats were allocated into 8 groups (n = 8) as follow; control, control + vitamin E, control + sitagliptin, control + sitagliptin + vitamin E, HFD, HFD + vitamin E, HFD + sitagliptin and HFD + sitagliptin + vitamin E. Control groups were fed with chow diet for 15 weeks, while HFD groups were fed with HFD for the same duration. Vitamin E and sitagliptin were administered in the last 4 weeks of the study. At the end of the 15th week, body weight, liver weight/body weight ratio, weight gain, glucose, lipid profile, liver enzymes, adiponectin and pro-inflammatory cytokines as interleukin 6 (IL-6), high sensitive C reactive protein (hs-CRP) and tumour necrosis factor-α (TNF-α) were measured. Additionally, gene expressions of senescence marker protein 30 (SMP30), Bcl-2, and Bax were measured. Total antioxidant capacity (TAC) and thiobaribituric acid reactive substances (TBARS) were assayed. HFD increased TBARS, IL-6, hs-CRP and TNF-α significantly and decreased TAC and adiponectin. Sitagliptin produced a comparable result through increasing adiponectin, sitagliptin alone or in combination with vitamin E increased the TAC, and gene expression of SMP30 and Bcl-2 and decreased TBARS with downregulation of the overexpressed Bax. Vitamin E, as a natural antioxidant, ameliorates the oxidative stress with insignificant change in lipid profile and inflammatory cytokine levels. Concomitant sitagliptin and vitamin E reduced the hepatic dysfunction induced by HFD.

Effects of low dose of aliskiren on isoproterenol-induced acute myocardial infarction in rats.

This study examined the effects of aliskiren (Ali) (direct renin inhibitor) on serum cardiac enzymes (LDH and CK-MB), electrocardiography (ECG) changes, myocardial oxidative stress markers (MDA, CAT, and GSH) and the expression of Bcl2, HO-1, and Nrf2 genes in isoproterenol (ISO)-induced myocardial infarction (MI). A total of 40 male albino rats were allocated into four groups, (1) normal control (NC) group, (2) Ali group (rats received Ali at 10 mg/kg/day p.o. for 5 days), (3) ISO group (rats received ISO 150 mg/kg i.p. for two consecutive days at 24 h intervals), and (4) Ali + ISO group (rats received ISO + Ali at 10 mg/kg/day p.o. for 5 days from the 2nd dose of ISO). ISO group showed significant rise in serum cardiac enzymes (CK-MB and LDH), myocardial damage scores, myocardial MDA, HO-1, myocardial Nrf2 expression with significant reduction in myocardial antioxidants (CAT and GSH), and Bcl2 expression compared to the normal group (p < 0.05). ECG showed ST segment elevation, prolonged QT interval and QRS complex, and increased heart rate in ISO group. Co-administration of Ali and ISO caused significant increase in cardiac enzymes and morphology with increase in MDA, serum K, and creatinine with significant decrease in Bcl2, HO-1, and Nrf2 without significant changes in ECG parameters compared to ISO group. We concluded that low dose of Ali seems to exacerbate the myocardial injury in ISO-MI, which might be due to the enhanced oxidative stress and apoptosis.

Melatonin ameliorates brain oxidative stress and upregulates senescence marker protein-30 and osteopontin in a rat model of vascular dementia.

The aim of this study was to investigate the effect of melatonin on oxidative stress and senescence marker protein-30 (SMP30) as well as osteopontin (OPN) expression in the hippocampus of rats subjected to vascular dementia (VD). A total of 72 male rats were divided into six groups (n = 12 each) as follows: (i) untreated control (CON), (ii) sham-operated group, (iii) sham-operated + melatonin, (iv) rats exposed to VD induced by permanent bilateral occlusion of the common carotid arteries (BCCAO) leading to chronic cerebral hypoperfusion, (v) rats exposed to VD + melatonin, and (vi) rats exposed to VD + donepezil (DON). At the end of experiment, the hippocampal levels of acetylcholine (ACh), norepinephrine (NE), and dopamine (Dop) were measured. Expression of OPN was determined using immunohistochemistry, and SMP30 expression was determined using real-time PCR in the hippocampus. Hippocampal thiobarbituric acid reactive substances (TBARS) and total antioxidant capacity (TAC) were evaluated. The BCCAO group showed significantly decreased TAC (p < 0.05) and significantly increased in TBARS levels compared with the CON group. In addition, BCCAO significantly decreased (p < 0.05) the expression of both OPN and SMP30 and the levels of ACh, NE, and Dop in the hippocampus compared with CON treatment. Treatment with melatonin significantly increased OPN and SMP30 expression and ACh, NE, and Dop levels in the hippocampus with amelioration of the oxidative stress compared with BCCAO rats. Melatonin might produce a neuroprotective effect through its antioxidant action and by increasing the expression of SMP30 and OPN that is not comparable with that of DON.

Effect of fluoxetine and resveratrol on testicular functions and oxidative stress in a rat model of chronic mild stress-induced depression.

Our objective was to investigate the effects of chronic unpredictable mild stress (CUMS) with or without selective serotonin reuptake inhibitor (fluoxetine) and anti-oxidant (resveratrol) on testicular functions and oxidative stress in rats. Fifty male rats were divided into 2 groups; control and CUMS. CUMS group was further subdivided into 4 subgroups administered water, fluoxetine, resveratrol and both. Sucrose intake, body weight gain, serum corticosterone, serotonin and testosterone levels, sperm count and motility, testicular malondialdehyde, superoxide dismutase (SOD), catalase, glutathione (GSH), and gene expression of steroidogenic acute-regulatory (StAR) protein and cytochrome P450 side chain cleavage (P450scc) enzyme were evaluated. CUMS decreased sucrose intake, weight gain, anti-oxidants (SOD, catalase, GSH), testosterone, serotonin, StAR and cytochrome P450scc gene expression, sperm count and motility and increased malondialdehyde and corticosterone. Fluoxetine increased malondialdehyde, sucrose intake, weight gain, serotonin and decreased anti-oxidants, StAR and cytochrome P450scc gene expression, sperm count and motility, testosterone, corticosterone in stressed rats. Administration of resveratrol increased anti-oxidants, sucrose intake, weight gain, serotonin, StAR and cytochrome P450scc gene expression, testosterone, sperm count and motility, and decreased malondialdehyde and corticosterone in stressed rats with or without fluoxetine. In conclusion, CUMS induces testicular dysfunctions and oxidative stress. While treatment of CUMS rats with fluoxetine decreases the depressive behavior, it causes further worsening of testicular dysfunctions and oxidative stress. Administration of resveratrol improves testicular dysfunctions and oxidative stress that are caused by CUMS and further worsened by fluoxetine treatment.

Effect of vitamin E on cerebral cortical oxidative stress and brain-derived neurotrophic factor gene expression induced by hypoxia and exercise in rats.

Brain-derived neurotrophic factor (BDNF) is involved in the proliferation of neurons, and its expression increases significantly with exercise. We aimed to investigate the effects of chronic exercise (swimming) and sustained hypoxia on cortical BDNF expression in both the presence and absence of vitamin E. Sixty four male Sprague-Dawley rats were divided into two equal groups; a normoxic group and a hypoxic group. Both groups were equally subdivided into four subgroups: sedentary, sedentary with vitamin E, chronic exercise either with or without vitamin E supplementation. Arterial PO(2), and the levels of cortical malondialdehyde (MDA), antioxidants (reduced glutathione GSH, superoxide dismutase (SOD), catalase (CAT) and vitamin E) and BDNF gene expression were investigated. Hypoxia significantly increased MDA production and BDNF gene expression and decreased the antioxidants compared to control rats. Chronic exercise in hypoxic and normoxic rats increased MDA level and BDNF gene expression and decreased the antioxidants. Providing vitamin E supplementation to the hypoxic and normoxic rats significantly reduced MDA and BDNF gene expression and increased antioxidants. We conclude that sustained hypoxia and chronic exercise increased BDNF gene expression and induced oxidative stress. Moreover, vitamin E attenuated the oxidative stress and decreased BDNF gene expression in sustained hypoxia and chronic exercise which confirms the oxidative stress-induced stimulation of BDNF gene expression.

Theoretical study of population inversion in active doped MIR chalcogenide glass fibre lasers (invited).

We study the mechanism of the population inversion in mid-infrared fibre lasers based on a chalcogenide glass host doped with active lanthanide ions. Three lanthanide dopant ions are considered: terbium, dysprosium and praseodymium. We predict the relevant trivalent ion level populations and gain. The simulation parameters were obtained by fabricating and optically characterising a series of trivalent ion doped chalcogenide glass samples. We also provide simple analytical expressions that aid the design of the cascade lasing process.

Superior photoluminescence (PL) of Pr³âº-In, compared to Pr³âº-Ga, selenide-chalcogenide bulk glasses and PL of optically-clad fiber.

The photoluminescent-(PL)-properties of Pr³âº-ions in indium-containing selenide-chalcogenide bulk-glasses are found to be superior when compared with gallium-containing analogues. We observe circa doubling of mid-infrared (MIR) PL intensity from 3.5 to 6 µm for bulk glasses, pumped at 1.55 µm wavelength, and an increased excited state lifetime at 4.7 µm. PL is reported in optically-clad fiber. Ga addition is well known to enhance RE³âº solubility and PL behavior, and is believed to form ([RE³âº]-Se-[Ga(III)]) in the glasses. Indium has the same outer electronic-structure as gallium for solvating the RE-ions. Moreover, indium is heavier and promotes lower phonon energy locally around the RE-ion, thereby enhancing the RE-ion PL behavior, as observed here.

Effect of dehydroepiandrosterone (DHEA) on memory and brain derived neurotrophic factor (BDNF) in a rat model of vascular dementia.

The effect of dehydroepiandrosterone (DHEA) on memory and cognition in experimental animals is well known, but its efficacy in clinical dementia is unproven. So, the aim of the present study was to investigate the effect of DHEA on learning and memory activities in a rat model of vascular dementia (VD). Forty-eight male rats that positively passed the holeboard memory test were chosen for the study before bilateral permanent occlusion of the common carotid artery. They were divided into four groups (n=12, each) as follows (i) untreated control, (ii) rats exposed to surgical permanent bilateral occlusion of the common carotid arteries (BCCAO) leading to chronic cerebral hypoperfusion, (iii) rats exposed to BCCAO then received DHEA (BCCAO + DHEA) and (i.v.) rats exposed to BCCAO then received donepezil (BCCAO + DON). Holeboard memory test was used to assess the time, latency, working memory and reference memory. Central level of acetylcholine, norepinephrine and dopamine in the hippocampus were measured. Furthermore, the expression of brain derived neurotrophic factor (BDNF) in the hippocampus was determined. Histopathological studies of the cerebral cortex and transmission electron microscope of the hippocampus were performed. BCCAO decreased the learning and memory activities in the holeboard memory. Also, it decreased the expression of BDNF as well as the central level of acetylcholine, noradrenaline and dopamine as compared to control rats. Treatment with DHEA and donepezil increased the working and reference memories, BDNF expression as well as the central acetylcholine in the hippocampus as compared to BCCAO rats. DHEA produced neuroprotective effects through increasing the expression of BDNF as well as increasing the central level of acetylcholine and catecholamines which are non-comparable to donepezil effects.

Effect of sitagliptin on the working memory and reference memory in type 2 diabetic Sprague-Dawley rats: possible role of adiponectin receptors 1.

Type 2 diabetes mellitus (DM) is associated with increased incidence of behavioral changes and memory loss. Memory loss could be caused by Alzheimer's disease (AD) and vascular dementia (VaD). So, we aimed to investigate the effect of sitagliptin in improving the working and reference memories in diabetic rats. Thirty six male Sprague-Dawley rats divided equally (n=12) into three groups: control, type 2 DM and type 2 DM treated with DPP-4 inhibitor (sitagliptin) for one month (10 mg/kg) orally. Working memory and reference memory were assessed by using the holeboard memory test. In all rats, serum glucose, insulin, adiponectin, total cholesterol (TC), TG, low (LDL) and high (HDL) density lipoprotein with calculation of the homeostasis model of assessment-insulin resistance index (HOMA-IR) and atherogenic index. The hypothalamus was separated for determination of the acetylcholine level and adiponectin receptors 1 (Adipo R1) m-RNA expression. Type 2 diabetic rats exhibited a significant decrease in both working and reference memories, with increased glucose, insulin and HOMA-IR. The adiponectin level, acetylcholine content of the hypothalamus and Adipo R1 m-RNA expression were significantly reduced. Treatment with sitagliptin significantly improved the working and reference memories with significant reduction in the glucose, insulin and HOMA-IR. Moreover, sitagliptin increased significantly the acetylcholine content of the hypothalamus and Adipo R1 expression. In conclusion, sitagliptin might improve the cognitive function of the diabetic rats and the hypothalamic acetylcholine level possibly through increased AdipoR1 expression.

Effect of testosterone replacement therapy on cardiac performance and oxidative stress in orchidectomized rats.

AIM: To investigate the effects of testosterone on myocardial contractility, oxidative stress status and expression of sodium channel protein (Nav1.5) and inward rectifying K channels (Kir 2.x) in normal and orchidectomized (ORX) rats. METHODS: One hundred four rats were randomly assigned into four groups (n = 26, each) as follows: (i) untreated controls, (ii) testosterone treated, (iii) orchidectomized rats and (iv) orchidectomized, testosterone-treated rats. Treatments with the vehicle or testosterone were carried out for 12 weeks, three times per week. At the end of treatment, surface ECG, isolated heart, tissue oxidative stress and lipid peroxidation experiments were carried out on the cardiac tissues. Also, immunohistochemical examination for Nav1.5 and PCR detection of mRNA of Kir2.1, Kir2.2 and Kir2.4 subunits of K channels were carried out. RESULTS: Orchidectomy impaired cardiac contractile function parameters left ventricular developed pressure (LVDP) and the peaks of the positive and negative pressure derivatives (dP/dtmax and -dP/dtmax respectively), increased heart rate and prolonged QT and QTc intervals, elevated pro-oxidant state in rat's hearts and decreased the expression of Kir 2.1 but not Kir2.2, Kir 2.4 and Nav1.5 channels. Exogenous testosterone administration to orchidectomized rats restored heart contractility and shortened QT and QTc intervals to their normal values, ameliorated the generated pro-oxidant state and improved the expression of Nav1.5 and Kir2.1, but not Kir2.2 or Kir2.4 channels. CONCLUSION: Testosterone improved cardiac contractility and shortened QT and QTc intervals in ORX rats. An effect that might be dependent of reduction in oxidative stress and enhancement of Kir2.1 channels but independent of Nav1.5 channel protein.

Modulation of metabolic and cardiac dysfunctions by swimming in overweight rats on a high cholesterol and fructose diet: possible role of adiponectin.

Western diet rich in cholesterol and sucrose with decreased physical activity cause overweight and metabolic syndrome. The aim of the present study was to investigate the effect of swimming on the cardiac adiponectin mRNA expression in high cholesterol and fructose fed rats. Forty Sprague-Dawley male rats divided into 2 equal groups. First group - control, that was fed with chow diet for 15 weeks. Second group was fed with high cholesterol and fructose diet (HCFD) for 15 weeks. Ten rats from both groups performed swimming during the last 4 weeks. After 15 weeks serum glucose, insulin, lipogram, leptin, resistin, adiponectin, and cardiac enzymes (lactate dehydrogenase and creatine kinase - MB) levels were measured. HOMA-IR index was calculated, evaluation of cardiac adiponectin gene expression using RT-PCR and cardiac histopathological examination were studied. Left ventricular developed pressure (LVDP), dp/dtmax and -dp/dtmax were measured by isolated Langendorff-perfused heart. Swimming exercise in rats fed HCFD resulted in improvement of the glucose homeostasis and lipogram with decreased leptin, resistin and HOMA-IR index with elevation in serum adiponectin. Also, there was an over-expression of down-expressed cardiac adiponectin gene. Also, ventricular functions were ameliorated by swimming exercise training. Swimming exercise partially improved the ventricular function that could be possibly explained through increased the cardiac expression of adiponectin.

Sequential docetaxel as adjuvant chemotherapy for node-positive or/and T3 or T4 breast cancer: clinical outcome (Mansoura University).

This trial compared 6 cycles of fluorouracil, epirubicin, and cyclophosphamide (FEC) with a sequential regimen of 3 cycles of FEC followed by 3 cycles of docetaxel (FEC-D) as adjuvant treatment for women with node-positive or/and T3 or T4 breast cancer. Between January 2006 and January 2010, 657 patients with operable breast cancer were randomly assigned to either FEC every 21 days for 6 cycles, or 3 cycles of FEC followed by 3 cycles of docetaxel, both given every 21 days. Radiotherapy was mandatory for all patients who had undergone breast conserving surgery. Radiation to the chest wall, supraclavicular area, was recommended following mastectomy. Hormone-receptor-positive patients received tamoxifen for 5 years after chemotherapy. The primary end point was 5-year disease-free survival (DFS). Median follow-up was 61 months. Five-year DFS rates were 74 % with FEC and 78 % with FEC-D (P = 0.013). Multivariate analysis adjusted for prognostic factors showed a 17 % reduction in the relative risk of relapse with FEC-D. Five-year overall survival rates were 85 % with FEC and 89.4 % with FEC-D, demonstrating a 27 % reduction in the relative risk of death (P = 0.014). The incidence of grade 3-4 neutropenia, the need for hematopoietic growth factor, and incidence of nausea/vomiting were higher with FEC. Docetaxel was associated with more febrile neutropenia, stomatitis, edema, and nail disorders. Though rare overall, there were fewer cardiac events after FEC-D, attributable mainly to the lower anthracycline cumulative dose. Sequential adjuvant chemotherapy with FEC followed by docetaxel significantly improves disease-free and overall survival in node-positive or/and T3 or T4 breast cancer patients. Although the magnitude of the benefit observed with FEC-D, differences in the toxicity profiles of FEC and FEC-D may influence the choice of treatment for patients.

Comparison of two planning systems for HDR brachytherapy gynecological application.

PURPOSE: This report compares the Nucletron NPS and PLATO planning system for patients treated for cervix cancer. MATERIALS AND METHODS: This study compares calculations generated using the older NPS (version 11.43) planning system and the more recent PLATO (version 14.1) system for two cases: 1) a single dwell position and 2) an actual patient application using a tandem and ovoid. RESULTS: For one dwell position: for NPS planning the dose for points along the source axis forward of the cable was 9.85% more than for symmetrically placed points in the cable direction. For PLATO, the same test gave rise to a difference of 10.2%. Comparing the two systems, NPS calculated doses for points in the forward direction 14% greater than those calculated by PLATO. The entry of points using the digitizer accounted for less than 1% of any difference. For the patient case: the dose difference between NPS and PLATO planning for all patient reference points entered from films ranged from 1 to 4%. The difference in dose between optimized and nonoptimized planning was approximately 0.5% for prescription points (points A), while for the bladder and rectum the differences were 6% and 20%, respectively with NPS, and with PLATO, 8% and 22%, respectively. CONCLUSION: This study highlighted the effects of the differences in the calculational algorithm between the older and newer planning systems from Nucletron. While the differences were minimal on the perpendicular bisector of the source, along the axis they become considerable. In a practical gynecological case, these differences mostly affect the dose to the rectum, since that organ receives the greatest proportion of its dose from rays near the same axis. Overall, the PLATO system plan required about 2.5% less integrated reference air kerma than the NPS plan for the same dose to point A. For either planning system, optimization is crucial in decreasing dose to bladder and rectal points.

Primary hepatocellular carcinoma: clinical, ultrasonic, and pathological patterns and correlations.

Twenty-seven patients with tissue diagnosis of hepatocellular carcinoma were reviewed retrospectively in an attempt to do a correlative study between clinical echographic patterns and the pathologic grading. The mean of the anterior hepatic linear projection (AHLP) was 33 cm; the surface was smooth in 26% and irregular in 30% and a single mass was detected in 44% of cases. Ultrasonically, three patterns were detected: 1) solitary mass in 66.6% of cases: hyperechogenicity in 22.2%, hypoechogenicity in 27.8%, and compound echogenicity in 50% of cases; 2) multiple masses in 25.9% of cases: hyperechogenicity in 71.4% and compound echogenicity in 28.6%; and 3) diffuse distortion of hepatic architecture with areas of heterogenous echopattern in 7.4% of cases. Pathological grading was carried out according to the generally accepted criteria, grades I in 29.6%, II in 33.3%, and III in 37.1% of cases. No correlation could be detected between the AHLP, patient age, sex, duration of complaint, or incidence of distant metastases and the pathologic grading. Also, there was no correlation between the duration of complaint and the AHLP. However, a significant relation was detected between the character of the hepatic surface and the pathologic grading; a smooth liver was associated with lower pathologic grading compared to either the surface with a single mass or to the irregular surface. On the other hand, no significant relation could be detected between lobar affection, ultrasonic pattern, or echogenicity and the pathologic grading.

Reduced prostaglandin synthesis by renal and aortic tissues from adult rats fed essential fatty acid-deficient diet after food deprivation.

Studies were conducted to determine the efficacy of a dietary technique for reducing prostaglandin (PG) synthesis in adult rats. Rats weighing 280-318 g were fed either essential fatty acid (EFA)-deficient or EFA-adequate diets for 10-17 days after a period of food deprivation. Synthesis of renal papillary PGE2 and aortic PGI2 from endogenous precursor in vitro were estimated by liquid chromatographic and bioassay/radioimmunoassay techniques, respectively, as indices of the capacity of the technique to induce EFA deficiency. PGE synthesis and PGI2 synthesis by isolated tissues from rats fed the EFA-deficient diet were significantly decreased (ca. 50%) relative to control rats fed an EFA-adequate diet. Body and renal papillary weights were not significantly altered by the EFA-deficient diet.

Enhanced renal vasoconstriction in rats fed essential fatty acid-deficient diet.

The effects of angiotensin II (ANG II) and norepinephrine (NE) on total renal blood flow (RBF) were studied in rats fed an essential fatty acid (EFA)-deficient diet. EFA deficiency was employed, as an alternative to the use of cyclooxygenase inhibitors, to investigate the influence of arachidonic acid metabolites on rat RBF. Intrarenal arterial (ira) bolus doses of ANG II (2-16 ng) and NE (25-100 ng) elicited significantly greater decrements in RBF and increments in renal vascular resistance in anesthetized Sprague-Dawley rats fed EFA-deficient diets than in control rats, which were fed EFA-adequate diets. Indomethacin (5 mg/kg iv) enhanced the vasoconstrictor responses to ANG II and NE in rats fed the EFA-adequate diet but not in rats fed the EFA-deficient diet. In rats fed regular laboratory chow the renal vasoconstrictor response to ANG II was potentiated after the administration of either indomethacin or naproxen (5 mg/kg iv). Methacholine and prostaglandins E2 and I2 caused dose-related renal vasodilatation when injected (ira) over the dose range of 10-40 ng in rats fed either the EFA-deficient or -adequate diets. The increased responsiveness of the renal vascular bed to ANG II and NE in rats fed EFA-deficient diets was not attributable to reduced vasodilator efficacy. Collectively, these results suggest that the net effect of endoperoxide products of arachidonic acid metabolism attenuates the vasoconstrictor influences of exogenous ANG II and NE in the intact rat kidney.