Changes in plasma kininogen levels induced by cellulose sulphate during pregnancy in the rat.

1 Cellulose sulphate (1 mg/kg) produced a 30-40% depletion of plasma kininogen in rats.2 The time course of repletion of kininogen in the plasma was compared in rats in the oestrous and dioestrous stages of the cycle and in 22 day pregnant animals. A partial repletion occurred, 3 h after the cellulose sulphate injection, which was followed by a secondary fall in plasma kininogen. Plasma kininogen values were back to control levels 10 h after the treatment in all groups.3 Treatment of rats from days 19-22 of pregnancy with cellulose sulphate resulted in 40% depletion of plasma kininogen and in prolongation of pre-parturition behaviour.4 It is suggested that the increase which normally occurs in plasma kininogen levels towards the end of pregnancy in the rat may play a role in the process of parturition.