Delaying action of gonadotrophins on ovulation in the hen.

Abstract

SummaryAntiadrenergic, anticholinergic or central depressant drugs suppress or delay, in varying proportions, ovulation of the second or C2 follicle of the hen's sequence following their administration some 18-20 hours before normally expected ovulation. In an attempt to counteract these effects, a whole anterior pituitary (AP) preparation from cocks was injected intramuscularly shortly before injection of several of the drugs. The incidence of suppressed ovulations was increased by the AP preparation, and increased proportions of suppressed ovulations exhibited C1 lapses, i.e., the normally expected C2 ovulation was delayed only until the hour of typical C1 ovulation on the day following its suppression. Intramuscularly injected 18-19 hours before expected C2 ovulation, the AP preparation alone suppressed ovulation in most hens, with a high proportion of C1 lapses. Under similar conditions, luteinizing hormone (LH) or follicle stimulating hormone (FSH) from cock pituitaries suppressed ovulation in some h...