Effect of amlodipine, fosinopril and atenolol on glucose metabolism and microalbuminuria in STZ diabetic rats

This study compares the effect of a calcium channel blocker [amlodipine], an ACE inhibitor [fosinopril] and a B 1-blocker [atenolol] on blood glucose level, plasma insulin level, insulin sensitivity and 24 hours urinary albumin excretion in groups of rats made diabetic by a single intraperitoneal injection of streptozotocin [STZ] [60 mg/kg]. Five groups of rats were used in this work. The first group [control non-diabetic rats] was normoglycemic with blood glucose level 116.8 +/- 9.4 mg/dl and 24 hour[H] urinary albumin 8.2 +/- 1.2 mg/24 H urine. The other four groups were made diabetic by a single dose of STZ. The second group [control non-treated diabetic rats] exhibited hyperglycemia 8 weeks after induction of diabetes with blood glucose level 354 +/- 32.6 mg/dl, plasma insulin level 10.1 +/- 0.8 mIU/ml and 24 H urinary albumin 42.6 +/- 3.2 mg/24 H wine. Results of this study revealed that amlodipine oral administration in a dose of 5 mg/kg for 8 weeks in the third group of STZ diabetic rats induced a significant reduction of blood glucose level [234 +/- 18.6 versus 354 +/- 32.6 in control diabetic rats, P< 0.05] and plasma insulin level [8.2 +/- 06 mIU/ml versus 10.1 +/- 0.8 mIU/ml in control diabetic rats, P<0.05]. Amlodipine also caused significant reduction in 24 H urinary albumin [18.2 +/- 1.2 mg versus 42.6 +/- 3.2 mg in control diabetic rats, P<0.05] and significant improvement in sensitivity to intraperitoneal bolus dose of insulin where it caused a significant reduction in blood glucose level at 0.5 H,1 H and 6 H after insulin compared to control diabetic rats, P<0.05. The results of this study also revealed that administration of fosinopril in a dose of 5 mg/kg/day oral to the fourth group of STZ diabetic rats for 8 weeks induced a significant reduction in blood glucose level plasma insulin level, and 24 H urinary albumin excretion compared to control non-treated diabetic rats. Fosinopril, also produced a significant improvement in insulin sensitivity at 0.5 H, 1 H and 6 H after insulin injection compared to control non-treated diabetic rats. In contrast, atenolol given orally in a dose of 10 mg/kg/day for 8 weeks to fifth group of diabetic rats did not induce a significant change in blood glucose level, plasma insulin level and 24 H urinary Albumin and even reduced insulin sensitivity compared to control non-treated diabetic rats. It could be concluded from these results that both amlodipine and fosinopril are better antihypertensives than atenolol in diabetic patients as they improved glucose tolerance and albuminuria in STZ diabetic rats

possible role for testosterone hormone on lipid peroxidation and some parameters of oxidant-antioxidant balance in rat myocardial tissue

The link between androgens and coronary artery disease remains elusive and the possible mechanisms that may relate testosterone to the development of cardiovascular diseases have not been well established yet. This study was designed to clarify the effect of testosterone hormone on lipid peroxidation and oxidants-antioxidant balance in rat myocardial tissue. Forty male albino rats included in this study were divided into 4 equal groups. Group [1] served as control rats and the other three groups were subjected to castration. One week after castration, group [2] rats were injected with solvent, group [3] rats received i.m. testosterone enanthate 10 mg/kg once weekly and group [4] received i.m.daily injections of vitamin E [alpha-tocopherol] in a dose of 20 mg/kg/day. All injections were continued for 4 weeks then all rats were sacrificed by decapitation and the hearts were obtained and prepared for the estimation of lipid peroxides as thiobarbituric acid reactive substance [TBARS], nitrite concentration, glutathione [GSH], glutathione peroxidase [GSH-PX] activity and vitamin E [alpha tocopherol]. TBARS and nitrites concentrations were significantly higher in the myocardial tissue extract of group [2] than group [1] rats while GSH and GSH-PX were sign lower, indicating that castration put the rat myocardial tissue under oxidative stress. However, in group [3] and group [4], TBARS and nitrites were sign lower and GSH and GSH-PX activity were sign higher than group [2], indicating that testosterone replacement therapy as well as vitamin E therapy protected the castrated rats from the oxidative stress and restored the oxidant- antioxidant balance in rat myocardial tissue. It could be concluded that testosterone may have a role in preserving oxidant- antioxidant balance in myocardial tissue of albino rats and this may be one of the mechanisms that could explain a suggested cardioprotective role of testosterone

Metabolic effects of high sucrose feeding on insulin action and triglycerides in male and female rates

The present study was undertaken to evaluate the changes in liver. muscle and serum triglycerides during high sucrose feeding and relationship of these changes to the appearance of insulin resistance and also to demonstrate if sex steroid hormones would protect against sucrose induced insulin resistance. 70 male and 70 female rats of the same age weight and strain were included in this study. All rats were housed individually and were given high starch diet [68% corn starch. 20% protein and 12% fat] for 1 week. then half of rats [35 male rats and 35 female rats] remained on the high starch diet for 2.5 and 8 week while the other half of rats were shifted to a high sucrose diet [68% sucrose. 20% protein and 12% fat] for 1,2,5 and 8 week. 11 male rats and 10 female rats were excluded from our study because their food intake was less than 90% of that provided. Serum glucose. insulin and triglycerides were estimated with liver and muscle triglycerides. In female rats, there were non significant changes in serum glucose, serum insulin serum triglycerides. liver and muscle triglycerides between high sucrose diet and high starch diet at 1.2,5 and 8 week. In male rats fed sucrose diet there was significant increase in serum insulin level at 2,5 and 8 week compared with high starch fed rats but there was non significant change in serum glucose between both groups. Serum and liver triglycerides were significantly increased in male rat fed sucrose diet at 2.5 and 8 week compared with starch fed male rate. We concluded that. high sucrose diet produces insulin resistance in male rats which is related to change in triglycerides concentration and female rats in contrast to male rats do not develop sucrose induced insulin resistance or hypertriglyceridaemia and the presence of estrogen and or progesterone or absence of male hormones may be protective in female rats against the impairment of insulin action on a high sucrose diet

role of autonomic innervation of the adrenal gland on the expression of corticosterone diurnal rhythm

Several lines of evidence indicate that alterations in sympathetic input to the adrenal gland may represent one of the routes by which adrenal responsiveness to circulating adrenocortico-trophic hormone [ACTH] is modulated. This study is designed to evaluate the role of autonomic innervation of the adrenal gland on the expression of corticosterone diurnal rhythm. This work was done on forty [40] rats divided into 3 groups. Group I is resting control group. Group II is divided into 2 subgroups. Subgroup II a was injected with dexamethasone while subgroup II b treated with dexamethasone and ACTH. Group III is splanchnicotomy group. Plasma corticosterone level was measured in blood samples from all groups at AM and PM. In dexarnethasone-treated rats, dexarnethasone reduced PM level of corticosterone without significant change in AM corticosterone level when exogenous ACTH was given to dexamethasone treated rats, corticosterone response was found to be without significant AM/PM difference. In splanchnic nerve transection group, splanchnicotomy resulted in a non significant change in AM corticosterone level, while PM corticosterone level reduced significantly. This result indicates that splanchnic neural input to adrenal gland facilitates resting PM corticosterone secretion

Effect of acupuncture on blood pressure: role of opioid peptides

The effect of electroacupuncture on experimentally norepinephrine induced hypertension was studied on albino rats. In normotensive rats no significant change was observed in blood pressure with acupuncture insertion. The effect on experimentally induced hypertensive rats was contrary. As while insertion of needle at St.36 point resulted in a significant decrease in blood pressure, needle inserted at Go. 26 point resulted in a significant increase in blood pressure. Naloxone administration before acupuncture failed to inhibit its effects on blood pressure, indicating that acupuncture mediates its effects via opioid receptors other than mu receptors

Role of opioid receptors in acupuncture induced changes in pituitary-adrenal axis in non-stressed and stressed rats

The aim of this work was to investigate the effects of acupuncture analgesia on pituitary-adrenal axis and to identify the role of opioid receptors in mediating these effects in non-stressed and stressed rats. The parameters studied were the ACTH, cortisol and glucose plasma levels. It was found that, in the group of non-stressed rats the acupuncture resulted in a significant increase in plasma ACTH and cortisol levels. Pretreatment of rats with naloxone before acupuncture resulted in nonsignificant difference when compared with rats subjected to acupuncture alone