groups of rats were also killed on days 8 , 15 , 19 , 22 and 23 and on the day of pro-oestrus of the 4-day cycle for the assay of progesterone , 20 alpha-dihydroprogesterone ( dhp ) , oestradiol-17 beta , lh and fsh .
C0033308
progesterone
C0012311
20