Steroid concentrations in rabbit oviducal fluid during oestrus and pseudopregnancy

The concentrations of progesterone and oestradiol in the oviducal fluid during oestrus and pseudopregnancy were measured. Progesterone concentrations ranged from 0.55 +/- 0.17 ng/ml during oestrus to a maximum of 2.86 +/- 0.82 ng/ml on Day 12 of pseudopregnancy. Serum progesterone concentrations were similar to those found in oviduct fluid during oestrus, but by Day 12 serum levels had risen to 14.13 +/- 1.97 ng/ml. Daily oviducal fluid oestradiol values ranged from 48.3 +/- 6.4 pg/ml to 119.7 +/- 23.6 pg/ml and were similar to serum concentrations.