[Biological assay of prostaglandin using the rat uterus]

Isometric contraction of rat uterus with PGF2alpha was more reliable and stable than when a stomach preparation was used. The method of PG bioassay using rat uterus was as follows: ovariectomized rats were given 10 mug of estrone s.c. 48 hr before the decapitation. Uterine strips were suspended in 2 ml of organ bath containing modified Locke-Ringer solution at 25 degrees C, and the isometric contraction was determined. As little as 4 ng/ml of PGF2alpha was determined quantitatively with this method.