Relationship between plasma and uterine oestradiol in pseudopregnant rabbits.

Plasma oestradiol concentrations did not change during hCG-induced pseudopregnancy except for a slight increase on Day 18. However, a marked decline was observed in tissue oestradiol on Day 3 whether expressed on the basis of tissue wet weight or protein. The lowest concentration was found at Day 6 but the Day 18 values were comparable to those of untreated controls.