Abstract
Although some studies have been reported on the concentration of estrogenic and gonadotropic substances in whole blood and serum during pregnancy, their number and accuracy have been limited by the large quantities of blood necessary for the biological tests employed.
By using unextracted sera as the test solutions, rather than extracts of blood or sera which contain only a fraction of the hormones, and mice, rather than rats, as the test animals, it was found that reliable results could be obtained with from 20 to 50 cc of blood.
Estrogenic Hormone. A modification of Fluhmann's technic 1 was employed. Whole or diluted serum was injected subcutaneously in 6 divided doses over a period of 3 days into castrated mice of approximately 8 weeks of age and 25 g in weight, beginning on the 8th day after oöphorectomy. The animals were sacrificed on the 4th afternoon. Biopsies were taken from the middle portion of the vagina and histologic sections prepared by a rapid technic. The least amount of serum which produced complete hyperplasia to vaginal cornification (reactions 4 to 5, Fluhmann) were regarded as containing 1 mouse unit. Also the uterine cornua were examined macroseopically for estrus, since macroscopically positive uteri indicated dosages several times the amount necessary to produce vaginal cornification.
For the initial titration 3 to 6 mice were injected with varying amounts of sera. When the approximate quantity necessary to produce cornification was found, 3 to 6 animals were injected with more closely grouped dosages. Further titrations were conducted if necessary. Six to 12 animals were generally used for each titration, while 3 to 6 animals were injected with amounts close to the finally accepted value.
The values obtained in 88 determinations on 26 pregnant women (Table I) were approximately 20 times greater than those of Smith, 2 who used ether extracts of whole blood.
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