THE (ESTRUS-PRODUCIXG HORMONE 109 



about the first day of menstruation, after wliich it rapidly 

 decreases. It is present in menstrual blood in larger amounts 

 than in the circulating blood. Frank also uses the blood oestrin 

 test to determine intersexual conditions. Eels (202) and 

 Trivino (615) found oestrin in the circulation only during 

 pregnancy. Aschheim (36) reports negative results from pre- 

 menstrual blood, inter-menstrual blood, and blood during 

 labour. 



During pregnancy, however, very considerable amounts of 

 oestrin are present in human blood, as shown by Zondek and 

 Aschheim (657), Eels (202), Trivino (615) and Smith (574). Eels 

 describes it as increasing rapidly in the circulating blood after 

 the sixth month of pregnancy, while Aschheim (36) found it 

 only after the fourth month. It is then so plentiful that 2 c.c. 

 of blood serum will give a positive reaction. 



The detection of oestrin in blood soon led to an examina- 

 tion of the possibility of its excretion. The presence of 

 oestrin in small amounts has been described in the urine 

 of the non-pregnant female (413), varying according to stages 

 of the menstrual cycle, but during pregnancy relatively 

 enormous amounts have been found by various workers, 

 including Aschheim and Zondek (38), Slotta (570), Zondek (648), 

 and Veler and Doisy (621) . Aschheim and Zondek (40) state that 

 it is doubtfully present during the first two months of pregnancy, 

 and as small amounts are found in the urine of the non-pregnant 

 female, this is not essentially a characteristic of pregnancy. 

 They described (38) the concentration in the urine of late 

 pregnancy as 1,000 m.u. per litre. Subsequently, the same 

 authors (40) gave the yield as 4,000-10,000 m.u. per litre 

 (see p. 168). The human female thus seems to excrete about 

 a million mouse units during pregnancy. The comparatively 

 rapid disappearance of oestrin from the urine after parturition 

 has been noted by Aschheim and Zondek (see p. 167) and 

 Veler and Doisy (621). The latter give their results as in 

 Table 7 (p. no). 



Occurrence in the male. The presence of oestrin in the testis 

 and also in the male body fluids has been reported by various 

 authors. Eellner (195), Laqueur and de Jongh (357). Brouha 

 and Simonnet (106) and Robinson and Zondek (538) have all 



