Survival of mouse ovarian tissue transplanted into the uterine horn of post-partum rats nursing pups of various numbers and sizes.

To investigate the effect of the number of pups being nursed on the survival of mouse ovarian tissue transplanted into the post-partum rat uterus.  Mouse ovarian tissue was transplanted into the uterine horn of post-partum rats. The number of pups nursed by each recipient rat was adjusted in a manner predetermined. Examinations were undertaken at 1-11 weeks after transplantation. Ovarian tissue containing healthy follicles was considered to have taken successfully. In rats with 12 pups, ovarian tissue remained viable at 11 weeks post-transplantation. No viable ovarian tissue remained when there were one or two pups. Viability improved as the number of pups increased. When mouse ovarian tissue is transplanted into post-partum lactating rats, viability improves as the number of pups increases. We concluded that these findings may be explained in terms of progesterone levels in the recipient rats. (Reprod Med Biol 2005; : 149-152).