Mechanical and metabolic effects of diazoxide in rat uterus.

Diazoxide relaxed both polarized and depolarized rat uterus. The drug also conteracted the contractions elicited by Ca2+ in a competitive manner. The relaxing effect was associated with an increase in the tissue level of cyclic AMP. This metabolic effect of diazoxide was inhibited by propranolol-treatment and in preparations from reserpinized animals, while the mechanical effects were only partially reduced. Diazoxide was also found to increase the release of tritium from preparations preloaded with [3H]-noradrenaline. It is suggested that diazoxide may induce some of its mechanical and metabolic effects by releasing the adrenergic transmittor substance noradrenaline. An effect of diazoxide on the Ca2+-metabolism is also probable.