Abstract
There are 7 preparations of the gonadotropic principle of human pregnancy urine in common use at the present time. All of these are standardized in rat units. However, each manufacturer defines his unit differently, using various criteria as a basis.
Estrous type of vaginal smear, follicular maturation and luteini-zation, and change in ovarian weight are some of the criteria employed. The age of the test animals, the time elapsed during the assay, and the number of injections, are also variables.
Since different quantities of the human urinary gonadotropic material are required to produce these criteria, and since an older test animal is more easily brought to maturation than a younger one, the commercial human urinary gonadotropic units are not comparable by definition alone.
D'Amour and D'Amour 1 have attempted to make an effective comparison of these units, employing ovarian weight as a criterion. We have adopted the estrous type of smear in 21-day-old rats as the criterion in our assays. All our animals were females of the Sherman strain, and at least 10 rats were utilized for each assay. All available human urinary gonadotropic products were then assayed by this method.∗
Daily injections of 0.5 cc of the test material were given sub-cutaneously for 3 consecutive days, and the animals were tested for the estrous type of smear at 120 hours following the initial dose. Their ovaries were examined grossly for evidences of maturation. A result was considered positive if at least 50% of the animals had an estrous type of smear.
If the number of rat units of the test substance first employed was insufficient to give a positive result, a greater number of units was injected into each of the next group of 10 rats.
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