Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU
(Received 9 February 1978)
It has been shown that prostaglandins play an important role in the mechanism of parturition in many species, including the goat (Currie & Thorburn, 1977; Thorburn, Challis & Robinson, 1977). Recently we have demonstrated that intra-uterine tissues from pregnant goats, when superfused in vitro, produce prostaglandins E and F (PGE, PGF) and 13,14-dihydro-15-oxo-prostaglandin F at various rates (Mitchell, Flint, Robinson & Thorburn, 1978). The exciting discoveries of two potent prostaglandin-like compounds, thromboxane A2 (TXA2; Hamberg, Svensson & Samuelsson, 1975) and prostacyclin (PGI2; Moncada, Gryglewski, Bunting & Vane, 1976), have radically altered our thinking on prostaglandins and basic data are urgently required concerning these compounds. Since prostaglandin endoperoxides are the immediate precursors of both prostaglandins and TXA2 (and PGI2) and since TXA2 has been shown to cause contraction of a number
