The use of preparations of urinary bladder smooth muscle for bioassay of and discrimination between polypeptides.

Eleven polypeptides, two prostaglandins and three amines were assayed, in parallel, by measurement of their spasmogenic effect on the isolated urinary bladder of eight animal species, the in situ bladder of three species and the isolated ureter of three species. Several of the smooth muscle preparations examined proved to be sensitive and suitable test-objects for the quantitative bioassay of different peptides. At the same time they appeared to be useful for discriminating not only between peptides belonging to different groups, but also between members of the same peptide family. It is tentatively suggested that biogenic peptides may interfere in the physiological control of motility and tone of the urinary tract smooth muscle.