Variation of spleen fibrinolytic activity in pregnant and puerperal mice.

A spleen fibrinolytic proteinase (non-plasmin) activity was measured in normal pregnant and puerperal mice. The weight of the spleen and blood parameters (APTT, PT, DBCL and fibrinogen level) were also examined.The normal pregnant mice were divided into two groups in accordance with their fetus length; group I: ≤1.5cm and group II: >1.5cm by the growing of the fetus. The changes of leukocyte count and PT were not significant compared with the control (non-pregnant). However, APTT was shortened, DBCL supressed and fibrinogen content slightly increased in group II. The spleen weight was significantly increased in the group I, while it recovered in group II. In the latter group, a apecial spleen fibrinolytic activity was remarkably enhanced by nearly three times compared with the control, in spite of the recovery of the spleen weight.The same examinations were made in the puerperal mice, either continuing lactation or non-lactation ones. The enhanced spleen fibrinolytic activity was slightly remained in both lactation and non-lactation groups 1-3 weeks after delivery. Results of other parameters were the same as those of pregnant mice.The inhibitor studies on the spleen extract indicated that the spleen fibrinolytic activity was not derived from plasmin but chymotrypsin like protease.