title: Inhibitory action of human serum on the isoprenaline-induced chronotropic effect in cultured rat heart cells. Influence of sex and pregnancy.
abstract: Cultures of beating rat myocardial cells brought into contact with various human sera during 24 hours were infused with isoprenaline. The isoprenaline-induced positive chronotropic effect (IIPCE) was not found with all sera. IIPCE was present in all the male sera, but was absent in the cases of clinically beta-blocked pindolol treated men. IIPCE was present only in about 50% of the female sera, menopaused or not. IIPCE was absent in 95% of the sera of pregnant women in the late phase of pregnancy. This suggests the presence in female sera, especially during pregnancy, of a circulating factor capable of "in vitro" inhibition of isoprenaline-induced positive chronotropic effect.
mesh_terms: D000328:Adult; D000818:Animals; D001769:Blood; D002478:Cells, Cultured; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D011247:Pregnancy; D051381:Rats; D012737:Sex Factors; D013268:Stimulation, Chemical
chemical_list: D007545:Isoproterenol