PHYSIOLOGY OF EGG EXTRUSION IN FEMALE XENOPUS FROG TEST FOR PREGNANCY11

Abstract

IN 1930, HOGBEN (1) first showed that anterior pituitary lobe extracts could cause external deposition of ova in the hypophysectomised mature female Xenopus laevis (the South African clawed frog). Following this original observation Hog-ben, Charles and Slome (2), Shapiro and Zwarenstein (3, 4), and Bellerby (5, 6) cor-roborated Hogben's finding. Hence the use of the female Xenopus as an assay animal for gonadotropic substances came into use in South Africa. In 1934, Shapiro and Zwarenstein (7, 8) and Bellerby (9) working independently, simultaneously suggested the use of the Xenopus frog reaction as a test for gonado-tropic hormones in pregnancy urines. Many confirmatory papers on this simple test for pregnancy were soon forthcoming (10–22). This characteristic extrusion of eggs by the female Xenopus is rapidly becoming widely used as a quick test for the early diagnosis of pregnancy.