THE HORMONES IN HUMAN REPRODUCTION 



tion of the gonadotrophic mechanism of the pituitary. These 

 upsets produced with long-continued or very large doses are 

 however not altogether pertinent. The theory calls for rela- 

 tively small fluctuations, within the body's normal range of 

 hormone production. On this hypothesis, however, the very 

 first period should be prevented, and this did not occur. If 

 my dosage of hormone was really physiological, as we say 

 (that is, something like the amount the animal herself would 

 produce) then the cstrin-deprivation hypothesis in its simple 

 original form is not adequate to explain the observed facts. 



Progesterone and menstruation. On the other hand, ad- 

 ministration of the corpus luteum hormone even in small 

 doses prevents menstruation in experimental animals, abol- 

 ishing the very first menstrual period after injections are 

 begun (provided they are started a few days before the ex- 

 pected onset). Both Hisaw and I have found that experi- 

 mental estrin-deprivation bleeding, produced by removal of 

 the ovaries or by discontinuance of a course of treatment with 

 estrogenic hormone, is prevented by small doses of proges- 

 terone. Smith, Engle and Shelesnyak at Columbia University 

 arranged an exceedingly vigorous condition of estrin de- 

 privation. Their monkeys were first given a course of gonado- 

 trophic hormone from the pituitary gland (see p. 141) to 

 stimulate the output of estrogenic hormone from the ovaries. 

 They were also given generous doses of estrogens for good 

 measure. These hormones were suddenly discontinued and at 

 the same time the ovaries were removed. In the face of all 

 these reasons for deprivation bleeding, modest doses of 

 progestin (crude progesterone) completely prevented hemor- 

 rhage. 



On the other hand, progesterone deprivation, like estrin 

 deprivation, invariably causes menstruation-like bleeding. 

 This was very clearly apparent in a series of my experiments 

 in which progesterone was given to normally menstruating 

 monkeys. During the injections, menstruation ceased. When 



{ 164 } 



