Effects of furosemide on the renal functions of the unanesthetized newborn rat

Hypothyroidism maintained reactive oxygen species-steady state in the kidney of rats intoxicated with ethylene glycol: effect related to an increase in the glutathione that maintains the redox environment

Our objective was to determine whether hypothyroidism protects against ethylene glycol (EG)-induced renal damage and whether the redox environment participates in the protection process. We used 36 male Wistar rats divided into four groups: (1) euthyroid, (2) euthyroid + 0.75% EG, (3) hypothyroid, and (4) hypothyroid + 0.75% EG. Hypothyroidism occurred 2 weeks after thyroidectomy. The parathyroid gland was reimplanted. EG was administrated for 21 days in drinking water. On day 21, the renal function was assessed and then the rats were decapitated. The left kidney was processed for histology, and the right kidney was used to determine the redox environment, oxidative stress, and the testing of the antioxidant enzymatic system. EG in euthyroid rats reduced the hydric and electrolytic balance and it also caused oxidative stress and renal damage. Hypothyroidism per se modifies the renal function causing a low osmolal and potassium clearance and the filtered load of potassium and sodium. In addition, there was an enhanced redox state because hypothyroidism increases the reduced glutathione concentration caused by a high activity of γ-glutamylcysteine synthase. Hypothyroidism is a protective state against EG because the changes in the renal function were smaller than in the euthyroid state. The oxidative stress and cellular damage were ameliorated by the hypothyroid condition. Also, the hypothyroidism-enhanced redox environment protects against EG-induced oxidative stress, renal damage, and renal dysfunction.

Indomethacin decreases furosemide-induced natriuresis and diuresis on the neonatal kidney

Indomethacin is used to pharmacologically occlude patent ductus arteriosus in preterm infants. It induces renal untoward effects and furosemide is administered simultaneously to counteract them. The effect of furosemide is blunted by indomethacin. We analyzed comparatively the interactions of furosemide and indomethacin at the organic anion transport system in adult and newborn individuals. Adult and 5-day-old Wistar rats were allocated into three groups: (1) indomethacin (10 mg/kg, ip); (2) furosemide (2 mg/kg, ip); and (3) indomethacin/furosemide, at the same doses. Urinary flow, glomerular filtration rate (GFR), sodium and potassium fractional excretions, and free-water and osmolal clearances were estimated. Para-aminohippuric acid (PAH) uptake was measured in renal cortical slices to study the organic anion's secretory pathway. In adult and newborn rats, furosemide-induced increments in urinary fluxes and excretions of sodium and potassium were blunted by indomethacin administered simultaneously. PAH uptake was decreased to a further extent by indomethacin than by furosemide, suggesting that inhibition of the diuretic effect might be related to competition in the secretion of furosemide. Inhibitory interaction between indomethacin and furosemide was achieved at approximately 10-fold lower concentrations in the newborn than in the adult rats, suggesting that tubular secretion in the neonate is more sensitive to the action of these drugs than in the adult individual.

Diuretic effect of the aqueous extract of Bidens odorata in the rat

The aerial part of Bidens odorata Cav., are used in Mexican Folk Medicine to treat renal diseases. The aim of this study is to measure the diuretic response to aqueous extract of this plant at doses of 41 and 166 mg/kg and to compare it with that induced by furosemide at 2 mg/kg. Aqueous extracts, furosemide or vehicle were administered orally to adult rats and the effects on sodium, potassium and water balance were assessed. Aqueous extracts at both doses and furosemide produced important and significant increments in urinary excretion of sodium, potassium and water in rats with respect to control group. This increase was dose dependent and aqueous extract at the highest dose induced a more marked sodium and water excretion than furosemide, potassium excretion increased but it was less than the one induced by furosemide. These results suggest that the aqueous extract of Bidens odorata induce diuretic response.