Abstract
Van Dyke and Wallen-Lawrence 1 have prepared an extract of fresh beef pituitary tissue (phyone) possessing marked growth promoting properties on the hypophysectomized as well as on the normal immature rat. This preparation was without effect on the gonads of such test animals. Phyone was consequently thought to contain only the growth promoting hormone of the pituitary gland, and to be free of the sex-stimulating factors known to exist in this gland.
We have assayed 3 different batches of phyone† upon juvenile chinchilla female rabbits from 12 to 13 weeks of age. Four litters of 4 rabbits each were employed. In each litter one rabbit was retained as an uninjected control. Two of the members of each litter were given 0.5 cc. of phyone either intravenously or subcutaneously for from 3 to 5 days. Since Leonard 2 has shown that a female rabbit, if fully adult, will ovulate upon the intravenous injection of phyone, the remaining rabbit in each litter was given a single intravenous injection of 1 cc. of phyone from the batch used on its own litter-mates. This single injection was without effect upon the ovaries of the juvenile rabbits, but 1 cc. samples from any batch invariably produced ovulation upon intravenous injection into an adult rabbit in oestrus. From this difference in response it is apparent that the young rabbits employed here were not sexually mature.
When given repeatedly, as described above, phyone produced marked follicular enlargement and extensive luteinization in the ovaries of the juvenile rabbits. No ovulation occurred, but numerous blood-points were produced. The degree of the response was proportional to the amount of phyone administered, and the route of injection caused no difference in the reaction obtained.
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