The study showed that ET 1 inhibits testosterone secretion of rat Leydig cells in vitro by combining with ETA and ETB.Mobilization of Ca 2+ may not flow from extracellular to intracellular.

• ET 1通过与ETA及ETB结合而发挥作用。 其Ca2 +的动员可能不是细胞外Ca2 +进入细胞内。