Influence of mycotoxins on spontaneous contraction in myometrial strips of prepubertal lamb.

The effects of mycotoxin zearalenone and their major metabolites alfa- and beta-zearalenol on spontaneous contractions in isolated lamb uterine smooth muscle were examined. The study was carried out on 20 female prepubertal lambs aged between 45 and 50 days. Myometrial strips were set up in two isolated organ baths (10 ml) at 37 C and were exposed to increasing concentrations (10_11 M–10_6 M) of these mycoestrogens and results were compared with the effect, at the same concentrations, of natural estrogen 17beta-estradiol. Our findings suggest that mycotoxins and 17beta-estradiol, at nanomolar concentrations, rapidly enhance phasic spontaneous smooth muscle contraction. In particular, zearalenone increases the uterine activity similarly to 17beta-estradiol. On the contrary, its metabolite alfa-zearalenol significantly inhibits myometrial contractility.