[Endogenous beta-adrenomimetic substance as a constituent of the adrenergic beta receptor blocking mechanism].

In order to reveal endogenous beta-adrenomimetic in the blood the authors proposed the biological testing of the serum and plasma on the isolated myometrium of the rat. For this purpose obsidan was used as a beta-adrenoblocker. It was shown that endogenous beta-adrenomimetic different from adrenaline was present in the blood of males, nonpregnant and pregnant females and parturients. Besides, its concentration increased in pregnancy and remained high early in labor.