Effect of Feeding and Fasting on Excretion of Phenobarbital in the Rabbit

Abstract

The present investigation was prompted by our observation of what appeared to be a circadian rhythm in the excretion of phenobarbital in rabbits 111. The effect was seen when the amount of phenobarbital excreted during each 6-hr period of urine collection was expressed as percent phenobarbital C14 per total C14 radioactivity in each sample, Since these initial observations were limited to 3 rabbits, the present investigation was undertaken to further establish the occurrence of the phenomenon. Further more, a mechanism is described through which the circadian rhythm in excretion is controlled in the rabbit.