endometrium was recovered from a total of 37 pigs sacrificed on d 4 , 10 , 12 , 16 and 19 of the estrous cycle and on d 10 , 12 , 16 and 19 of gestation to determine whether the concentrations of cytoplasmic and nuclear estrogen receptors were altered during pregnancy .
C0014939
estrogen
C0032961
pregnancy