The effect of novel steroidal oestrogens on isolated rat thoracic aorta rings. Cumulative concentration response curves were constructed in rubbed (•) and unrubbed (□) aortic rings. Ligands tested were (A) 17β-oestradiol (n = 12), (B) DME-oestradiol (n = 6), (C) Quat DME-oestradiol (n = 7), (D) Oestrone (n = 11), (E) DME-oestrone (n = 6), (F) Quat DME-oestrone (n = 6), (G) Oestrone oxime (n = 7). Rubbed versus unrubbed rings were compared by two-way anova (*P < 0.05).