the release of prostaglandin e ( pge ) and prostaglandin f ( pgf ) into the medium , and their concentration in the zygotes after incubation , increased sharply on days 6 and 7 of pregnancy , reaching , by day 7 , values close to 200 ng of each pg released in 1 h per mg of protein .
C0033559
prostaglandin e
C0033554
pg