986 



SPERM, OVA, AND PREGNANCY 



Goss (1943), on the other hand, concluded 

 that the endometrial cups are the source of 

 the hormone. Recent evidence tends to con- 

 firm the endometrial cups as the source of 

 the hormone (Clegg, Boda and Cole, 1954). 

 The endometrial cups form in the endo- 

 metrium opposite the chorion in the area 

 where the allantoic blood vessels fan out. 

 The cups develop precisely at the time when 

 the hormone is first obtained in the serum 

 of the pregnant mares and desquamation of 

 the enclometrial cups is complete at the time 

 of the disappearance of the hormone from 

 the maternal blood. Analyses of the cups for 

 gonadotrophin content reveal a correlation 

 between the concentration of the hormone in 

 the maternal blood and the concentration in 

 the endometrial cups. Finally, histochemical 

 stains for glycoprotein indicate the presence 

 of this substance only in the epithelial cells 

 lining the uterine lumen and the uterine 

 glands in the cup area ( for complete discus- 

 sion of the subject see the chapter by Wis- 

 locki and Padykulal. 



VI. Pregnancy Tests 



The discovery of gonadotrophic activity 

 in the urine of pregnant women by Asch- 

 heim and Zondek in 1927 led to introduction 

 of the first valid test for pregnancy (Asch- 

 heim and Zondek, 1928). These investigators 

 used the innnature mouse and reported the 

 presence of corpora hemorrhagica as indica- 

 tive of the presence of a gonadotrophin in 

 the urine and a positive reaction for preg- 

 nancy. The Aschheim-Zondek test for preg- 

 nancy was the first successful test of its kind 

 and has been used both as a qualitative and 

 quantitative test. In the latter instance, a 

 serial dilution of the urine is made in order 

 to obtain the minimal effective dose. 



It is not too surprising that many tests 



for pregnancy have been described. In gen- 

 eral, all of the successful tests involve the 

 detection of chorionic gonadotrophin in the 

 urine, and to some extent in the blood. The 

 changes that have appeared in the develop- 

 ment of new pregnancy tests have been 

 those concerned with the use of different 

 species of animals, the rapidity with which 

 the test could be completed, and conven- 

 ience to the laboratory. Thus the Friedman 

 test (Friedman, 1929; Friedman and Lap- 

 ham, 1931 ) followed soon after the Asch- 

 heim-Zondek test and in turn was suc- 

 ceeded by several newer tests. 



Ap])roximately five reliable tests are now 

 available (Table 16.6). All are concerned 

 with the detection of HCG and have an ac- 

 curacy of 98 to 100 per cent. The Aschheim- 

 Zondek suffers from a time requirement of 

 96 hours and was largely supplanted by 

 the Friedman test that used the isolated 

 rabbit and required only 48 hours. Within 

 recent years several new tests have been 

 reported using the frog, toad, and imma- 

 ture rat. Frank and Berman (1941) first 

 noted the occurrence of hyperemia in the 

 ovary of the immature rat, following the 

 injection of HCG. Albert (1949) reported 

 excellent results with the use of this test 

 in 1000 cases. Comparison of the rat hy- 

 peremia test with the Friedman test was 

 on the whole very good and revealed the 

 same order of accuracy for both tests. The 

 Friedman test, however, will detect about 

 5 I.U. of HCG which would mean a concen- 

 tration of 500 I.U. of HCG per 24-hour out- 

 put of urine ( assuming a 24-hour urine out- 

 put of 1500 ml.). Positive results in the rat 

 test require a 24-hour output of 1000 I.U., 

 indicating that the ovarian hyperemia test 

 in the rat is about one-half as sensitive as 

 the Friedman test. Nevertheless, the rat 



