THE EFFECT OF OXYTOCIN ON HAND BLOOD FLOW IN MAN FOLLOWING THE ADMINISTRATION OF AN OESTROGEN AND ISOPRENALINE

Hot flushes during breast feeding?

The initiation of breast-feeding was accompanied by an increase in skin conductance followed by increased skin temperature. The pattern was similar to that observed during a menopausal hot flush and differed from sympathetic arousal and simple heating.

The distribution time of intravenously injected raffinose and inulin in intact animals and the effect thereon of sex and infusion of oxytocin

1. 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.

The effect of oxytocin on blood vessels of cremaster muscle of the rat

Oxytocin administered intravenously to the anaesthetized rat produced dilatation of the blood vessels of the cremaster muscle at concentrations ranging from 2.5 times 10-minus 11 to 2.5 times 10-minus 9 M. When applied topically to the exposed vessels it produced constriction at concentrations ranging from 2.5 times 10-minus 12 to 5.0 times 10-minus 8 M. Oxytocin was thus similar to adrenaline in eliciting opposite effects when applied to the serosa or to the intima of skeletal muscle blood vessels.