Operational correlates of prostanoid TP receptor expression in human non‐pregnant myometrium are unaffected by excision site or menstrual cycle status of the donor

Abstract

1 Cumulative concentration-e ect curves for the selective prostanoid TP receptor agonist, U46619, were constructed in strips of human non-pregnant myometrium grouped according to tissue excision site (top, lateral wall, lower uterine segment, sub-serosal or sub-endometrial), tissue orientation (strips cut either parallel or perpendicular to the serosa) and donor menstrual status (proliferative or secretory phase). 2 U46619 was excitatory in all tissues. There was no signi®cant di erence in either pEC 50 or maximum response between groups (P50.05). The range of pEC 50 values was 6.8+0.1 (lateral wall, proliferative phase, n=5) to 7.1+0.3 (lateral wall, secretory phase, n=5). The range of maximum response values was 0.9+0.8 N cm 72 (lateral wall, proliferative phase, n=5) to 3.1+1.0 N cm 72 (lateral wall, secretory phase, n=5). 3 Saturation binding analyses were conducted using the radiolabelled TP receptor agonist, [ 125 I]-BOP. Binding parameters were estimated for membranes prepared from human non-pregnant myometrium excised from the lateral wall and grouped according to donor menstrual status.

Effect of the oestrous cycle, pregnancy and uterine region on the responsiveness of the isolated mouse uterus to prostaglandin F2α and the thromboxane mimetic U46619

“…Our data have shown that there are no differences in the response to U46619 between the different stages of the oestrous cycle. This was comparable with data obtained from non-pregnant human myometrium that suggested that the response to U46619 is not influenced by menstrual status (Senchyna & Crankshaw 1999).…”

“…Regional variation in responsiveness to PGF 2 has also been observed in human myometrium taken during labour, with the lower segment showing little responsiveness to PGF 2 (Wikland et al 1984). However, the population of TP receptors is purported to be functionally homogenous throughout the human myometrium (Senchyna & Crankshaw 1999).…”

“…The response to U46619 in non-pregnant human myometrium is not believed to be dependent on the excision site (Senchyna & Crankshaw 1999); unfortunately this information is not available for myometrium from pregnant and labouring women at present.…”

Loss of prostaglandin F2α, but not thromboxane, responsiveness in pregnant human myometrium during labour

“…Significant attenuation with selective TP antagonists SQ29,548 and GR32191B confirmed TP-mediated responses in this study. In uterine muscle from non-pregnant donors, in vitro responses to U46619 were irrespective of menstrual status and excision site (Senchyna & Crankshaw 1999) and functional potencies were analogous to myometrium from term pregnant, non-labouring donors (Senior et al 1992(Senior et al , 1993. In addition, no regional or labour-related changes in the expression of TP receptor genes were detected in isolated baboon myometrium (Smith et al 2001).…”