study of the effect of estrogen hormonal modulation on liver ischemic reperfusion in rats

Ischemia/reperfusion [I/R] injury of the liver impaired hepatic regeneration and predisposed to liver failure. The prime factors contributing to injury are decreased nitric oxide [NO] level which favor vasoconstriction, increased production of reactive oxygen species [ROS], increased level of adhesion molecules and leukostasis, which further impair the hepatic microcirculation in the early reperfusion phase. Heat shock protein 70 [HSP70] was shown to be induced by stress. Of the present work was to study the effect of estrogen hormonal modulation on hepatic injury during I/R model in male rats and to investigate the possible involvement of HSP 70 in the gender dimorphic response of the liver to this injury. Forty adult male albino rats were used in this work. They were divided into 5 groups [each of eight rats]; eight rats were taken as normal sham operated group.The remaining rats were subjected to total hepatic I/R. Each group received a specific treatment given intraperitoneally [ip] including: 17-beta estradiol [E[2]], raloxifene [Ral.] and genistein [Gen.] one hour before surgical procedure. The sham operated rats were injected with the veichle dimethyl sulfoxide solution. The I/R group was pretreated with the vehicle. Several parameters including: serum transaminases, HSP 70, ROS, Myeloperoxidase activity[MPO] and nitrite content were measured using standard assay procedures. I/R produced a significant increase in serum transaminases, MPO and ROS in liver tissue. HSP 70 was induced to a significantly higher level in I/R versus sham operated group but nitrite was significantly reduced in I/R versus sham operated rats. E[2+] I/R group had significantly lower transaminases, MPO and ROS versus I/R untreated group. A significantly higher nitrite level and HSP 70 was detected in liver tissue of E[2+] I/R versus I/R group. Ral.+I/R group showed significant lower serum transaminases, MPO and ROS in liver tissue versus I/R. Also Ral+ I/R showed significant higher nitrite and HSP70 versus I/R group. Gen.+I/R group showed decreased serum transaminases, lower MPO and ROS versus I/R. Nitrite level was significantly higher in Gen.+I/R versus I/R .Compared to E[2+] I/R or Ral.+I/R, geinstein pretreatment showed significantely lower HSP70. 17-beta estradiol pretreatment produced significant protection during hepatic I/R injury through multiple pathways. The protection was related to HSP70 induction, greater NO release, inhibition of ROS and MPO activity in liver tissue. Both the synthetic estrogen receptor modulator [SERM] raloxifene and the phytoestrogen genistein exerted significant estrogen agonist protective effects on the liver I/R injury. The mechanism of raloxifene protection was similar to estradiol, although protection due to genistein pretreatment did not involve HSP70 induction. Protection by genistein could be attributed to enhanced NO release and inhibition of ROS

Effect of centrally and peripherally administered obestatin on food and water intake in rats

This work was designed to study the effects of acute obestatin administration on food and water intake, as well as on body weight in rats. In addition, the effect of blocking the efferent cholinergic vagal fibers on food intake was also tested in search for a possible mechanism of action. The study was carried out on 48 adult male rats with weight ranging from [185-200] grams and was divided into 3 sections. Section A intracerebroventricular [ICV] injection: consisted of 24 rats that were divided into 4 groups [6 / group]. Rats in group 1 served as control and were injected with ICV saline. Rats in groups 2, 3, 4 were injected ICV obestatin in doses 15, 25, 50 nM/kg, respectively. Section B intraperitoneal injection: Which included 24 rats divided into 4 groups [6 / group]. Rats in group 1 were injected with IP saline [control group]. Obestatin was injected by IP route in the other groups: 2, 3, 4 in doses of 50, 100, 1000 nM/ kg, respectively. Cumulative water and food intake were monitored at 1, 3, 6 and 24 hours after both ICV and IP obestatin injection and were expressed per rat. Plasma osmolality was measured at 3 and 6 hours after ICV and IP obestatin injection. The differences in body weight of rats were recorded at the end of 24 hours. Section C: rats in the 2 groups injected with the highest doses of obestatin [50 nM/kg ICV and 1000 nM/kg IP] were selected the following day and pretreated with atropine sulphate IP in a dose of 500 ug/kg.15 minutes before they were reinjected with obestatin in the same doses used in the previous day. Food and water intake were assessed after 3 hours of injection. ICV and IF injection of obestatin revealed a significantly lower water intake versus the control that appeared at 3 hours after ICV [15 nM/kg obestatin] and also at 3 hours after IP [100 nM/kg obestatin]. With higher doses of obestatin injection [ICV 25 and 50 nM/kg and IP 1000 nM/kg] the inhibition of water intake showed a significant dose dependant effect at 1 and 3 hours. Plasma osmolality showed no significant difference when compared between the studied groups after both ICV and IP obestatin injections at 3 and 6 hours. The inhibition of food intake occurred only at 3 hours with the highest doses of obestatin injected [ICV 50 nM/kg and P 1000 nM/kg] compared with the control group. No significant differences were detected in water and food intakes and also in body weight differences after 24 hours compared with the control after obestatin injection by either ICV or P routes. As regards testing the possible involvement of vagal efferent cholinergic mechanism in obestatin's action, the groups injected with the highest doses of obestatin [50 nM/kg ICV and 1000 nM/kg IP] 15 minutes after atropine premedication as well as the non pretreated groups showed a significant decrease of water and food intake at 3 hours compared with the control group. Furthermore, there were no statistically significant differences between atropine pretreated and non pretreated groups injected by the highest obestatin doses as regards food and water intake. Obestatin primarily has an effect to inhibit thirst after acute administration probably by an effect on one of the circumventricular organs. It has a weaker effect on food intake. may be because it has to diffuse to food regulating centers in the brain or because the food intake is regulated by several peptides that may antagonize each other. The vagus efferent cholinergic mechanism has no role in the inhibitory effect of obestatin on food intake. Obestatin should gain more attention as a peptide regulating water balance rather than food intake and its effect on angiotensin II and vasopressin should be investigated

possible role of visceral adiposity in development of pro-atherogenic lipid profile in normal overweight young Egyptian female adults [a possible involvement of adiponectin and leptin]

The metabolic abnormalities that often co-exist with overweight and obesity appear to be mediated largely by visceral fat accumulation. Visceral fat is very different from the subcutaneous fat, and may be responsible for pro-atherogenic lipid profile in apparently healthy people. to examine the influence of visceral fat and "not obesity" on the lipid profile. In addition, to test the relation between adipocytokines [leptin and adiponectin] and lipid profile in overweight young healthy Egyptian adult females. Forty healthy young overweight females participated in this prospective cohort study, their age ranged from 19-23 Y, and their body mass index [BMI] ranged from 25-30 Kg/rn2. All the participants were completely healthy with no history of thyroid dysfunction; diabetes; or cardiovascular, renal, or liver dysfunction. No participant had taken medication for at least 3 months before the study, and none were dieting or smoking. The anthropometric measurements were made be the same observer in the physiology laboratory, Alexandria University, they induced: height, weight, body mass index [BMI], waist, hip circumference and waist hip ratio [WHR]. Fasting venous blood was collected to measure adipocytokines [leptin and adiponectin] and lipid profile [total cholesterol [TC], total triglycerides [TG], high-density hpoprotein cholesterol HDL-C, low-density lip oprotein cholesterol [LDL-C] and the LDL-C/HDL-C ratio was calculated as the atherogenic index. Then the examined subjects were divided into two groups based on their Waist/hip ratio [WHR]. Group 1 [n 25 with WHR>0.8], and group2 [n=15 with WHR

Body composition and serum leptin level in Egyptian growth hormone deficient short children

Aim: This work was designed to evaluate the effect of growth hormone [GH]- deficiency on body composition and serum leptin level in Egyptian GH-deficient [GHD] short children. In addition, the relationship between serum leptin level, gender and anthropometric variables was also determined. Subjects and This study was conducted on 28 GHD children [19 boys and 9 girts] and 12 healthy controls [6 boys and 6 girls]. All children were prepubertal. Except for GH deficiency, the children were otherwise healthy with no evidence of organic diseases, chromosomal abnormalities, skeletal dysplasia or any other endocrinological disturbances. In all studied subjects, anthropometric parameters [weight, height, body mass index [BMI], waist/hip ratio [WHR] and subcutaneous skinfold thickness] were measured. To determine body composition, body fat percent [BF%] was calculated from subcutaneous skinfold thickness by specific equations from which the amount of total body fat mass [FM] and fat free mass [FFM] were calculated. Serum GH levels were estimated, using IRMA, under basal conditions and after applying two provocation tests [after exercise and after clonidine stimulation]. GH peak and GH area under the curve [GH AUC] were determined following clonidine stimulation. Baseline values of insulin-like growth factor-l [IGF-I] and leptin were also estimated in serum samples by ELISA. FFM was significantly lower in GHD children than controls. GHD children had a significantly higher BF% as compared to controls. Although FM showed a tendency to be higher in the GHD than the control group, the difference was statistically insignificant. Serum leptin level and leptin values, expressed per unit fat mass [ng/ml/kg], were significantly higher in GHD cases compared with controls. Significant positive correlations were detected between serum leptin and indices of adiposity [BMI, WHR, BF% and FM] in cases and controls. Multiple linear regression analysis with serum leptin considered as the dependent variable revealed that 52.6% of the variability of serum leptin level in GHD cases was significantly attributed to BF%,GH peak, GH AUC and IGF-I level [F= 8.480*, P= 0.000]. Healthy and GHD girls had a significantly higher BF%, FM and serum leptin levels than the boys of the corresponding group. However, leptin levels adjusted for fat mass did not differ significantly between boys and girls in each group. Conclusions: GH deficiency resulted in a significant increase of BF%. Serum leptin and leptin per unit fat mass were significantly higher in GHD cases. These findings suggest that GH could have an additional direct effect on leptin production from adipose tissue independent of its influence on body composition. Gender difference in serum leptin level is not obvious before puberty when the total body fat mass is taken into consideration

Central versus peripheral actions of adrenomedullin in a hypertensive rat model

Adrenomedullin [AM] is a peptide with potent vasorelaxing and natriuretic properties originally isolated from human pheochromocytoma. It may function as a circulating hormone that is involved in the regulation of cardiovascular system, renal function and hormone secretion. It has been observed that the hypotensive effect of AM in the periphery is not matched by a similar effect when injected centrally. The mechanisms involved in the peripheral hypotensive and central hypertensive actions of AM in normal rats are controversial and diverse; moreover in hypertension the underlying mechanisms are not tackled till now. 120 male albino rats were used in this study to assess the mechanisms involved in the peripheral versus the central actions of AM in the rat model. Hypertension was induced in 90 rats using NG-nitro-L-arginine ester [L-NAME] and ten normal rats were used as a control group. The peripheral and central actions of AM were tested in the hypertensive rats and in another 20 normal rats. The 90 hypertensive rats were divided into nine equal groups. Peripherally, AM was either injected alone [group I-A] or following a two-weeks of oral administration of prazosin [0.55 mg/kg/day], propranolol [14.4 mg/kg/day], valsartan [14.4 mg/kg/day] or isosorbide dinitrate [10.4 mg/kg/day] [groups II-A to V-A respectively]. Centrally, AM was either injected intracerebroventricularly [icv] alone [group I-B] or following a bolus icv injection of saralain [10 micro g] [group II-B] or after a two-weeks of oral administration of prazosin [0.55 mg/kg/day] or clonidine [18 micro g/kg/day] [group III-B and IV-B respectively]. Mean arterial blood pressure [MABP], plasma renin activity [PRA] and aldosterone level values were compared before and after AM injection in the same rate of each group. A 40.6% drop in MABP was elicited in normal rats injected peripherally with AM. This drop was attenuated to 18.6% in L-NAME hypertensive rats. The percent age drop in MABP in hypertensive rats pretreated with isosorbide dinitrate [43.3%] was comparable to that observed in normal rats when AM was injected intravenously to both groups [p=0.999]. A significant decrease in PRA and aldosterone level was produced in hypertensive rats pretreated with various drugs following the peripheral administration of AM as compared to their pre-injection values. On the other hand, a significant further increase in MABP was obtained following the icv injection of AM to L-NAME hypertensive rats pretreated with saralazin [P=0.000]. The changes observed in MABP, PRA and aldosterone level after the central administration of AM to hyptertensive rats pretreated with either clonidine or prazosin were insignificant as compared to their pre-injection values. This study suggests that the peripheral vasodilator effect of AM is mediated partially via nitric oxide release or probably by other mechanisms. The central hypertensive response to AM in the L-NAME rat model is probably not mediated by angiotensin-II receptors. It could be through enhancing the central sympathetic discharge via an action on either alpha 1, alpha 2 or the suggested imidazoline receptors located centrally. Finally, AM is supposed to be involved in the physiological resetting of renin-angiotensin-aldosterone system possibly secondary to changes in either catecholamines discharge or nitric oxide level. These results were discussed

Interrelationship between nitric oxide synthase and myocardial tumor necrosis factor-alpha effect on cardiac contractile function in preconditioned anesthetized dogs

Brief periods of myocardial ischemia and reperfusion render the myocardium tolerant to a subsequent sustained ischemia. This phenomenon has been known as ischemic preconditioning [PC]. It has recently become apparent that ischemic PC consists of two phases: an early phase, which occurs within minutes and disappears within 2 to 4 hours from the PC ischemia, and a late phase, which becomes manifest 24 hours later. The purpose of the present study was to test the hypothesis that the protective effect of ischemic PC is mediated by augmented nitric oxide [NO] formation. This study also aims at examining the effect of ischemic PC on postischemic myocardial tumor necrosis factor-alpha [TNF-alpha] production. This study was carried out on 38 healthy adult dogs of either sex. Six dogs were sacrificed and left ventricular myocardium was excised, homogenized and cardiac TNF-alpha homogenate was determined by chemiluminescence. Thirty-two dogs were randomized into 4 equal groups; Group I [preconditioned group], Group II [ischemic control group], Group III [preconditioned N-nitro-L-arginine methyl-ester [L-NA] treated group] and Group IV [ischemic L-NA treated group]. All groups were allowed 3 hours of reperfusion thereafter. Left ventricular systolic pressure [LVSP] and cardiac output [COP] were measured before and after left anterior descending coronary artery [LAD] occlusion reperfusion [O/R] in the four studied groups. After the three hours of reperfusion, TNF-alpha was measured in the cardiac homogenate of all groups. There was no statistically significant difference in LVSP and COP when comparing the four groups after LAD O/R However, there was a significant drop in both parameters in each of the four studied groups after LAD O/R. The absent short-term beneficial role of PC on myocardial contractility following O/R could be attributed to stunning of the myocardium: Furthermore, inhibition of NO synthesis did not attenuate myocardial stunning in preconditioned and ischemic anesthetized dogs. The present study also demonstrated that O/R increases cardiac TNF-alpha levels and that ischemic PC decreases ischemia-induced cardiac TNF-alpha production, which is still significantly higher in the preconditioned groups, compared with control group. This drop in myocardial TNF-alpha following ischemic PC did not improve postischemic functional recovery in anesthetized dogs. The absent short-term beneficial role of pretreatment with a NOS inhibitor could be explained by the fact that inducible NO synthase [iNOS] mediated only the late dysfunction induced by TNF-alpha