Study of the influence of ranitidine and phenylbutazone on oral iron absorption in rabbits

The present study aimed at evaluating the effect of prolonged oral administration [10 days] of ranitidine hydrochloride [10 mg/kg] and phenylbutazone [100 mg/kg] along and with ferrous sulfate [10 mg/kg], on the bioavailability of iron for intestinal absorption. Also, post absorption plasma iron tolerance curve was done to all groups. Fifty adult male rabbits were arranged into a control group, a ranitidine group and a phenylbutazone group. Ranitidine produced a significant decrease in plasma iron level when used alone [24.60%] as well as when given simultaneously with ferrous sulfate [12.82%], while phenylbutazone whether given alone or with ferrous sulfate produced a statistically insignificant rise plasma iron [6.32% and 12.90%, respectively]

Can captopril or propranolol reverse the unwanted metabolic effects of thiazide therapy?

The effects of captopril [CAP], propranolol [Prop] and/or hydrochlorothiazide [HCTZ] on serum electrolytes [Na, K], blood lipids [cholesterol, triglycerides [TG], blood glucose, uric acid and creatinine were studied in rabbits. HCTZ produced marked hypokalemia, hypercholesterolemia, hypertriglyceridemia, hyperglycemia, hyperuricemia and elevated the serum creatinine level. CAP raised both serum K and creatinine levels; however, it decreased serum cholesterol and TG levels. On the other hand, Prop caused a significant decrease in serum cholesterol and TG. HCTZ + CAP produced none of the unwanted metabolic effects of HCTZ, except for significant rise of serum creatinine level. On the contrary, HCTZ + Prop produced hypokalemia, hypertriglyceridemia and hyperuricemia, but the serum creatinine level was significantly lowered. So, it was recommended to use HCTZ + CAP as an anti-hypertensive combination in patients with high cardiovascular risks, while HCTZ + Prop seems to be a desirable choice for hypertensive patients with renal impairment

Alteration of blood pressure response to arachidonic acid in diabetic rats

The dose dependency and mechanism of arachidonic acid [AA]-induced decrement in systemic blood pressure [BP] was investigated in diabetic rats, versus their controls: Intravenous [I.V.] injection of 0.5-2 mg AA into diabetic rats [2 weeks after a single S.C. injection of alloxan, 175 mg/kg] caused dose dependent decrement in BP. The diabetic rats displayed decreased responsiveness to the hypotensive effect of AA compared to control rats. AA hypotensive responses were completely abolished by indomethacin [5 mg/kg I.V.]. Prostaglandin F2gamma [PGF2gamma], 20 ug, and norepinephrine [NE], 4 ug, increased BP whereas acetyloholine [ACh], 2 ug, lowered it in both diabetic and control rats. No significant differences were detected for the effects of the above mentioned drugs between the two groups. The findings indicate that AA is converted into cyclo-oxygenase derived products with predilection to formation of excess vasoconstrictor[s] metabolites and/or depressed vasodilator[s] production

Adrenergic hyperresponsiveness of abrupt atenolol withdrawal: possible involvement of prostaglandins

Abrupt cessation of chronic B-adrenoceptor blockers administration has been advocated to result in a rebound phenomenon for which several mechanisms have been postulated. However, this study was designed to investigate the changes in cardiac and fat B-adrenergic receptors responsiveness and the possible involvement of prostaglandins in such changes after abrupt withdrawal of chronic atenolol therapy in normal albino rats. In the first part of the study heart rate [HR] and blood pressure [BP] responses were determined before and 2 and 5 minutes after intraperitoneal injection of isproterenol [isuprel] in a dose of 0.2 ug/kg. Isuprel administration to normal rats resulted in a significant increase in HR and BP, whereas atenolol administration for 21 or 24 days resulted in a significant decrease in HR and BP and obtunded the effect of isuprel administration. However, after 3 days of atenolol withdrawal significant increments in HR and BP were obtained. Isuprel injection, at this stage resulted in significant increases of HR and BP compared to their initial control or to their respective control values. In rats receiving indomethacin [15 mg/kg/day subcutaneously in 2 divided doses] during atenolol withdrawal period [3 days], BP was maintained at significantly low level, whereas HR retained its preatenolol level. Moreover, indomethacin resulted in significant inhibition of isuprel influence on HR and BP compared to control values. In the second part of the study the effect of atenolol withdrawal as well as the influence of isuprel on B[1] receptors of fat cells were determined through estimation of free fatty acids [FFA] in plasma of rats. In the control group isuprel infusion stimulated FFA release after 5,10 and 15 min. Atenolol administration for 21 or 24 days did not change basal FFA level, however, it blocked the isuprel stimulated release. Atenolol withdrawal did not affect FFA basal level, nevertheless, isuprel stimulated significantly FFA release. Furthermore, administration of indomethacin during atenolol withdrawal showed no effect on basal or isuprel stimulated release of FFA compared to control group. However, isuprel infusion resulted in significant rise of FFA compared to its initial value. In conclusion this study has demonstrated that prostaglandins may be partially involved in the hypersensitivity of B-receptors occurring in normal rats after withdrawal of chronic atenolol treatment

Antiepileptic drugs and oral contraceptives

The present work was conducted to investigate the effect of some of the popular antiepileptic drugs on the efficacy of oral contraceptive pins containing D-norgestrel 0.15 mg and ethinyl oestradiol 0.03 mg in adult female non-pregnant rats. Oral treatment started while the animals were in the oestrus stage of their cycle. Drugs were administered orally for twelve successive days. Half the animals in each group was isolated and the other half was kept with males during the period of treatment. The oral contraceptive used caused a significant increase in both estrogen and progesterone levels compared to the control group. No pregnancies occurred in female rats kept with males during the period of treatment in this group. The simultaneous administration of the oral contraceptive with clonazepam [12.5 mg/kg/day] caused insignificant change in the level of estrogen and progesterone compared to the contraceptive group. No pregnancies occurred in this group. While the concurrent administration of the oral contraceptive with sodium valproate [150 mg/kg/day] resulted in a significant decrease in the levels of both estrogen and progesterone compared to the contraceptive group and insignificant change compared to the control group. Seventy percent of the female rats kept with males in this group became pregnant. On the other hand, the combination of this oral contraceptive with sulthiame [50 mg/kg/day] caused no change in the level of estrogen while progesterone level was significantly decreased compared to the contraceptive group reaching a level nearly that of the control group. No pregnancies occurred in this group. In conclusion we would emphasize that sodium valproate caused failure of the oral contraceptive used in this study. The same cannot necessarily be assumed for other contraceptive drugs. Even though we feel that patients under antiepileptic drugs should be advised as a precaution to use other contraceptive methods in addition to the oral contraceptives

Effect of captopril and ramipril on serum cortisol, T3, T4, some trace and ordinary elements in the rabbit

The effect of two angiotensin converting enzyme inhibitors, captopril [10 mg/kg/day] and ramipril [0.5 mg/kg/day] on the serum level of cortisol, T[3], T[4], copper, zinc, iron, calcium and magnesium were studied in adult male rabbits. The results showed that ten days oral administration of either captopril or ramipril caused no change in serum cortisol while T[3] and T[4] showed a significant decrease. Serum zinc level was significantly decreased with captopril while no change was observed after ramipril. No significant changes were observed in the serum level of copper, iron, calcium and magnesium with the tested drugs

Effect of Ca++ chaxrnel blocking agents on experimental hyperthyroidi in the dog

This work was designed to study the effect of Ca++ channel blockers [verapamil and nifedipine] on hormonal release and actions in hyperthyroidistn. In hyperthyroid crisis, intravenous verapamil decreased serum tniodothyronine [T[3]], blood pressure, heart rate and double product cardiac output index and succeeded to reduce the encountered supraventnicular and ventricular arrhythmias. Nifedipine decreased the blood pressure and double product index, yet it did not induce any significant effect on thyroid honones or blood lipids. In chronic hyperthyroidiam, verapamil increased serum lipids and controlled nearly all cardiovascular complications of the disease. Nifedipine increased both serum triiodothyronine and tetraiodothyronine [Thyroxine, T[4]], as yell as free fatty acids [FFA]. It controlled hyperthyroid hypertension, but failed to control the rest of the existing cardiovascular ccniplications

Effects of Ca++ channel blocking agents on pituitary thyroid hormones, serum lipids and cardiovascular functions in euthyroid dogs

The effect of verapamil and mifedipine was studied in euthyroid dogs to detect whether these drugs alter pituitary-thyroid output and/or actions. Verapamil induced a significant decrease of serum TSH, T[3] and T[4] as well as significant increase of serum lipids. It also exhibited a bradycardiac action. Nifedipine decreased only serum T[3] and induced a significant increase in serum FFA and total cholesterol. It also led to a decrease in diastolic pressure and an increase in heart rate

Brain amino acids neurotransmitters, under clinical anesthesia in experimental animals

The effect of four anaesthetic drugs: Two inhalational anaesthetic: Halothane, enflurane and two intravenously used anaesthetics: Ketamine hydrochloride and diazepam were investigated. Their effect on whole rat brain content of gamma amino butyric acid [GABA], L. Glutamic acid and their enzymes: Glutamic acid decarboxylase [GAD] enzyme activity and gamma aminobutyric alpha Ketoglutamic trans-aminase [GABA-T] enzyme activity were studied. Forty eight rats were subjected to anaesthetic agents and twenty-four were used as control. Halothane anaesthesia for 30 minutes in 12 rate produced significant decrease in L-glutamic acid level insignificant decrease in GABA, GAD-entyme activity and no change in GABA-T enzyme activity. Engurane anaesthesia for 30 minutes in 12 rats produced significant decrease in GABA and GAD-enzyme activity and produced significant increase in L-glutamic acid and GABA-T enzyme activity. Ketamine anaesthesia in a dose of 50 mg/kg in 12 rats produced significant increase in GABA, GAD-enzyme activity, significant decrease in L-glutamic acid content and insignificant change in GABA-T enzyme activity. Diazepam anaesthesia in a dose of 10 mg/kg in 12 rats produced significant increase in GABA, GAD-enzyme activity and significant decrease in L-glutamic acid content and GABA-T enzyme activity. From the results, a correlation between the GABA level in the brain with excitatory or inhibitory anaesthetic actions could not be concluded. Anaesthetic agents studied resulted in increase or decrease in GABA content of the whole rate brain by various mechanisms. Anaesthesia therefore is not to be expected as result from an increase in brain GABA content only

comparison of trimethoprim sulphamethoxazol with oxytetracycline and placebo in acne vulgaris

This comparative study included 30 patients to detect the effect of trimethoprim-sulfamethoxazole as compared with oxytetracycline or placebo for treatment of Acne vulgaris. Analysis of the results revealed that both drugs had a beneficial effect on Acne vulgaris and if compared with oxytetracycline, patients on trimethoprim-sulfamethoxazole showed antiseborrheic effect. during therapy

Effect of clonazepam and diazepam on the level of some amino acids in the rat brain

The effect of two benzodiazepine drugs: clonazepam and diazepam on gamma-aminobutyric acid [GABA] and L-glutamic acid contents of the whole rat brain were studied. Clonazepam in a single dose [0.1 mg/kg body weight] produced a significant increase in the level of GABA and L-glutamic acid. Repeated injections of clonazepam for 10 days [0.1 mg/kg body weight] produced a significant increase in GABA and insignificant change in L-glutamic acid content. On the other hand a single dose of diazepam, [5 mg/kg body weight] produced a significant decrease in GABA and L-glutamic acid levels. Repeated injections of diazepam [5 and 10 mg/kg body weight] for ten days produced insignificant effect on both amino acids