Activity in the corpora lutea resulting from sterile matings in Clethrionomys glareolus: a histochemical study

The capacity for steroid production in the corpora lutea (CL) of bank voles was examined by enzyme histochemistry for 3 beta-hydroxysteroid dehydrogenase. The results revealed similar activity in the CL resulting from sterile matings and the CL of pregnancy 2 days after mating. Six days after mating, the CL of pregnancy showed a strong reaction, while there was almost no reaction in the CL from sterile matings, which were clearly regressed at this time. It is suggested that the CL from sterile matings produce progesterone before regression and that this progesterone may prime the luteotrophic complex, increasing fertility of subsequent matings.