Abstract
Evans et al 1 found that the simultaneous injection of extracts of the anterior pituitary and prolan from pregnancy urine, resulted in a greater effect on the ovaries of immature rats than could be accounted for by the additive effects of the 2 preparations when injected alone. Their theory is that prolan does not act on the ovaries directly but activates the anterior lobe growth hormone so that it becomes the agent which causes the ovarian growth. Leonard 2 found that anterior lobe preparations which contained the gonadotropic substances but were free from growth hormone, would produce augmentation effects when injected in combination with prolan, thus showing that the growth factor was not essential for the reaction. We reported 3 that an anterior lobe luteinizing preparation which produced little or no increase in weight of the immature ovaries when given alone, would augment the action of a given dose of a follicular stimulating preparation. These results, together with others, were interpreted as showing the presence of 2 gonad stimulating hormones. We have now succeeded in separating the 2 principles more completely 4 and have studied the ovarian effects when the 2 are recombined and injected, or used in combination with prolan and the anterior lobe-like hormone of human placentae.
The follicular stimulating extract, in the dosages employed, usually produced only follicular growth, though slight luteinization was present in a few cases. The luteinizing preparation had no noticeable effect on the ovaries of immature rats even when 25 mg. of the luteinizing powder was given. In the present experiments only 5 mg. were used. Castrated horse pituitary powder 5 was also used as a source for follicular stimulating hormone. Prolan was prepared from pregnancy urine by acetone precipitation followed by pyridine extraction and the placental hormone from dried human placentae by the same general method used for pituitary powder.
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