Induction of blastocyst implantation in mice by cyclic AMP.

Oestrogen administration to female mice with 'delayed' implantation induces changes in the uterus and blastocysts followed by implantation and normal gestation. The second messenger for oestrogen, adenosine 3' :5'-cyclic monophosphate (cAMP), was instilled into the uterine lumen of females with 'delayed implanting' blastocysts to determinewhether it also is able to induce implantation. Implantation of the blastocysts was induced by cAMP but the pregnancies were not maintained to tem. These results are discussed with respect to the changes in blastocysts induced by cAMP and with respect to the reported contraceptive effects of cAMP in normal mice.