Increased sperm output of rabbits and bulls treated with prostaglandin F2α

Abstract Seven rabbits were ejaculated four times once weekly, and saline or 2.5 mg PGF 2α tromethamine salt was injected sc at 4 and 2 hours or at 8 and 4 hours before ejaculation. First ejacula taken at 2 hours after the second injection of PGF 2α contained 150% more ( P ⋍.07 ) sperm than those after injections of saline. The comparable difference (60%) at 4 hours after PGF 2α was not significant. PGF 2α did not influence sperm output in second, third or fourth ejacula. After 28 daily sc injections of 5 mg PGF 2α in another experiment, the fertility of four treated rabbits was as high as that for four controls. Without sexual preparation in seven bulls, im injections of 40 or 80 mg PGF 2α 30 minutes before ejaculation resulted in 33% greater (P 2α , but the highest sperm output after PGF 2α was 30% less (P 2α result in increased sperm output in ejacula taken without sexual preparation within 2 hours in rabbits and in bulls.