Chronopharmacological study of furosemide; (VIII) influence of feeding restriction.
We have previously reported that a time-dependent variation is observed in the diuretic effect of furosemide and the light-dark cycle is a potent zeitgeber for this chronopharmacological phenomenon of the agent in rats. The present study was undertaken to examine whether a time of food intake is another zeitgeber for this event. In study I, rats were maintained with free access to food for 3 weeks. Furosemide (30 mg/kg) was given orally at 12 am or 12 pm. Urine was collected for 8 hours after the agent and urinary excretion of sodium and furosemide were determined. Thereafter, these rats were maintained under a daytime-restricted feeding schedule (9 am-11 am) for 3 weeks (study II) and a night-time-restricted feeding schedule (9 pm-11 pm) for 3 weeks (study III). The identical protocol of study I was repeated at the end of study II and III. Diuretic effect of furosemide and its urinary excretion were significantly greater at 12 am than at 12 pm in study I and III. However such an administration time-dependent change in the effect of furosemide and its urinary amount disappeared in study II. These data indicate that a time of food intake is another potent zeitgeber for the time-dependent variation in the diuretic effect of furosemide.
Department of Clinical Pharmacology, Jichi Medical School, Tochigi, Japan.
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Fujimura
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Ohashi
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Ebihara
D000818:Animals; D002940:Circadian Rhythm; D004231:Diuresis / Q000187:drug effects*; D004435:Eating / Q000502:physiology; D005665:Furosemide / Q000494:pharmacology* / Q000652:urine; D008297:Male; D009318:Natriuresis / Q000187:drug effects*; D011897:Random Allocation; D051381:Rats; D011919:Rats, Inbred Strains
D005665:Furosemide