Changes in Prostaglandin E₂ Levels in Seminal Plasma during Ejaculation and the Effect of Exogenous Prostaglandin E₂ on Semen Volume in the Dog

Abstract

In healthy male dogs, peripheral plasma testosterone (T), prostaglandin E₂ (PGE₂) and seminal plasma PGE₂ levels were measured before, during and after ejaculation, and semen quality was examined after oral administration of PGE₂. Plasma T and PGE₂ levels did not change during these periods, but the seminal plasma PGE₂ level of combined the first and second fractions was significantly higher than those at 0–5 and 5–10 min after the start of ejaculation of the third fraction. Semen volume but not quality increased after PGE₂ administration. In conclusion, large amounts of PGE₂ are released from the prostate gland during the early part of ejaculation, and PGE₂ plays an essential role in secretion of seminal plasma.