Effect of a vasopressin analogue (Nalpha-glycyl-glycyl-glycyl-[8-lysine]-vasopressin) on organ blood flow in the pregnant guinea pig.

Nalpha-triglycyl-(8-lysine)-vasopressin (TGLVP) was administered intravenously to pregnant guinea pigs and the effect on regional blood flow examined by the radioactive microsphere technique. A dose of 10 mug/kg TGLVP caused an elevation of the mean arterial blood pressure, from 6.4 to 11.1 kPa, a significant reduction in blood flow to the gut, skin and skeletal muscle and a significant increase in blood flow to the spleen. The number of 15 +/- 5 mum microspheres reaching the lungs diminished significantly after 10 mug/kg TGLVP, indicating that this dose constricted arterio-venous short circuits in the systemic circulation. There was also a decrease in blood flow to the urogenital tract, including the placentae. When 3 mug/kg TGLVP was injected, the mean arterial blood pressure rose from 6.5 to 8.7 kPa and there was no longer any consistent effect on maternal placental blood flow. It is suggested that pregnancy constitutes a contraindication for TGLVP, since a reduction in uterine and maternal placental blood flow might occur with clinically relevant doses.