Genomic and non-genomic effects of steroidal drugs on smooth muscle contraction in vitro.
The effect of steroidal drugs on KCl (60 mM)-induced tonic contraction in in vitro rat uterus has been assayed. Ouabain had no effect and aldosterone only relaxed the KCl contraction up to 27 +/- 7.3%. However, estradiol, testosterone, progesterone, cortisol and alphaxalone relaxed the contraction in a dose-dependent way, and CaCl2 (0.1 to 6 mM) counteracted this effect. Cycloheximide (1 and 10 micrograms/ml) did not modify the effect of progesterone, testosterone or alphaxalone. Cycloheximide, but not actinomycin D (5 micrograms/ml), reduced the effect of cortisol. Both cycloheximide and actinomycin D shifted righward the relaxing effect of estradiol. This suggests that the steroidal relaxing effect in smooth muscle is preferably non-genomic and at plasma membrane level. However, cortisol and estradiol also act at intracellular levels and induce transcriptional (estradiol) or non-transcriptional (cortisol) effects.
Departamento de Medicina, Facultad de Medicina, Oviedo, Spain.
M
M
Gutiérrez
V
V
Martínez
B
B
Cantabrana
A
A
Hidalgo
D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000494:pharmacology; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013256:Steroids / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects*; D014590:Uterine Contraction / Q000187:drug effects
D012739:Gonadal Steroid Hormones; D013256:Steroids; D011189:Potassium Chloride; D003513:Cycloheximide