title: Inhibitory effects of sexual steroidal hormones on the responses of the isolated guinea-pig lleum to acetylcholine and histamine.
abstract: Six sexual steroidal hormones (progesterone, pregnenolone, testosterone, ethinyl-oestradiol, oestriol and oestrone) inhibit acetylcholine- and histamine-induced contractions of the isolated guinea-pig ileum. Different degrees of inhibitory capacity were found. High concentrations of PGE1 and F2alpha reverse some of these inhibitions. This reversal seems to be non-specific and probably related to sensitization of the ileal smooth muscle by prostaglandins. The inhibitory action of sexual steroids might be non-specific as well. But a "corticoid-like" effect cannot be excluded.
mesh_terms: D000109:Acetylcholine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000818:Animals; D012739:Gonadal Steroid Hormones / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D006633:Histamine Antagonists; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D011458:Prostaglandins E / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology
chemical_list: D012739:Gonadal Steroid Hormones; D006633:Histamine Antagonists; D011458:Prostaglandins E; D011460:Prostaglandins F; D006632:Histamine; D000109:Acetylcholine