Premature Ovulation in the Domestic Fowl following Administration of Certain Barbiturates

Abstract

Ovulatory reactions of the first follicle of the hen''s ovulation sequence to barbiturates, and to barbiturates with progesterone, are described. Ovulation occurred prematurely in a significant proportion of hens following admn. of some barbiturates (Dial, Ipral and Nembutal), rarely with barbital, and not at all with phenobarbital. Near subovulatory dosages of progesterone acted synergistically with Dial and Nembutal which themselves cause premature ovulation an effect not found when progesterone was similarly admd. with phenobarbital. Prematurity of ovulation following the admn. of effective barbiturates probably results from neural excitation secondary to depression, excitation causing, over a humoral pathway, release of ovulation-inducing gonadotropin from the anterior pituitary body.