LH/hCG receptor has been found in extragonadal tissues in human and animals. The myometrium presents such receptors but their functional role is still not clear. Aim of our study was to test the activity of human chorionic gonadotropin (hCG) on bovine uterine contractility. Uterine strips from cows both during follicular and luteal phases were mounted in an organ bath and then exposed to increased doses of hCG. The amplitude of the myometrium contractions were significantly decreased in the follicular and luteal phase but the frequency was not affected. These findings prove a relaxing effect of hCG in the bovine uterus, as already shown in the sow and human, and its possible functional role in modulating uterine contractility.

Rosiglitazone is a drug used in human medicine for treating type II diabetes mellitus. It activates Peroxisome Proliferators-Activated Receptors gamma (PPAR-gamma), which regulate energetic metabolism. We aimed to evaluate the effects of rosiglitazone on bovine myometrial contractility in vitro. Myometrial strips were collected from uteri of cows in estrus, diestrus, and pregnancy. Contractions were recorded using an isometric force transducer. After the equilibration period, rosiglitazone (1 x 10(-6)) was added to the bath. Its effects on the amplitude and frequency of spontaneous contractions were evaluated. Data were analyzed using an ANOVA and Student's t-test and were considered significant at P < 0.05. Rosiglitazone increased the mean amplitude during estrus (P < 0.01), diestrus (P < 0.05), and pregnancy (P < 0.01); the frequency of contractions in both pregnancy (P < 0.05) and diestrus (P < 0.05) increased as well. These effects are likely due, in our opinion, to an increase in intracellular calcium concentrations, as well as enhanced uptake of glucose from the Krebs' solution. The differences observed according in the different phases are ascribable to the different hormonal milieu. Our study indicates that rosiglitazone affects bovine myometrial contractility. It may be considered a starting point for further studies on the application of this drug in veterinary obstetrics.

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