Table 2. Incorporation of cells rat XEN-P cell lines into postimplantation conceptuses.

No. of Expts.	Cell line	Host species	Injected embryos	Implanta-tion sites	Regressed embryos	Recovery Day	VYS	PYS	Unclear
3	RX1	Rat	30	24	5	8.0–11.5		1
4	RX5	Rat	59	39	9	8.5–9.5	1	7
3	RX1	Mouse	34	25	15	7.0–8.0	2	6	1*
4	RX5	Mouse	59	37	20	7.5–8.5		7
						Sum (%)	3 (12)	21 (84)	1* (4)

A total of 145 rat and 168 mouse embryos were injected and transferred in 13 and 15 experiments, respectively. Included in the table are only those experiments in which labeled cells could be recovered in a structure of the intact conceptus, including visceral yolk sac (VYS) endoderm and parietal yolk sac (PYS) endoderm. (*) Abnormal embryo with a patch of fluorescent cells.