Table 2. Concentration of endometrial tissue P4 in the cranial part of the ipsilateral and contralateral horns.

Stages (n)	Endometrial tissue P4 (ng/g)
	Ipsi-horn	Contra-horn	Overall means
ELP (6)	32.6 ± 3.7	15.9 ± 2.0	24.3 ± 3.2
MLP (6)	25.8 ± 1.4	14.4 ± 2.7	20.1 ± 2.2
LLP (5)	18.8 ± 3.7	12.5 ± 2.7	13.7 ± 2.4
Overall means	26.1 ± 2.1a)	14.4 ± 1.4b)

a, b) Significant differences at P<0.01 between the horn ipsilateral to a CL (ipsi-horn) and horn contralateral to the CL (contra-horn). The luteal phase was divided into three stages (ELP, early luteal phase, n=6; MLP, mid-luteal phase, n=6; and LLP, late luteal phase, n=5). Results are presented as the mean ± SEM.