In anaesthetized dogs whose renal pedicles were ligated the distribution time for I.V. administered raffinose was noted. In males the plasma concentration of raffinose fell for 7-10 min from the time of injection and in females it fell for 12-15 min; thereafter in both sexes the plasma concentration remained constant. 2. During I.V. infusion of oxytocin 10 mug/kg. min, the distribution time for raffinose was 12-16 min in males and 4-6 min in females. 3. During the period before stabilization of plasma concentration the concentration of raffinose was higher in the femoral artery than in the vein in both sexes. 4. In anaesthetized rats whose renal pedicles were ligated the distribution time for I.V. injected inulin was 7-8 min in males and 5 min in females. 5. Following alpha-adrenoceptor blockade with phentolamine the distribution time in both male and female rats was 14-15 min. 6. The sex differences in distribution time, both in normal and oxytocin-treated dogs, may be related to the state of contraction and differential sensitivity or pre- and post-capillary blood vessels and hence, of capillary pressure.
