220 



Discussions 



cornification 96 hr after the first injection; one month after hypophyscctomy, LH 

 0.32 fig twice daily for 3 days was effective in 50% of the animals tested (Table 2). 

 FSH, ACTH, GH and LTH were without cfTcct. 



Thus, from Dr. Ast wood's experiments (Emlocrinohi^y 28, 309, 1941) it would 

 appear that the secretion of progesterone by the corpus luteuni of the rat may be 

 under the control of LTH, and from Dr. Parlow's study that the secretion of estrogen 

 may be under the control of LH. This demonstration of a luteotropic action of LH 

 in the rat tends to place the corpus luteum in physiologic alignment with the adrenal 

 cortex and its response to ACTH. 



Table 2. The Effect of LH and FSH administered 80 Days after Hypophysectomy 



UPON the Secretion of Estrogen by Corpora Lutea persisting in the Ovaries of 



Rats which had been pre-treated with PMS and HCG. 



Dr. Roy O. Greep: I am very much interested in this observation. I well remember the 

 experiments with HCG and the available luteinizing hormone in hypophysectomized 

 adult female rats. I was greatly impressed with the fact that the LH then available 

 would knock out the corpora lutea in 48-72 hr. Admittedly the LH was not pure 

 and did produce some follicle stimulation. Later, at the Squibb laboratories we 

 obtained a luteinizing preparation that was more highly purified. I tried the same 

 experiment again and it did not work. I did not smear the animals and could very 

 well have missed a response in terms of estrogen secretion as Dr. Parlow has now 

 described. 



Dr. Sturgis raised the point that it isn't the estrogens that cause the secretion of 

 LH, but the metabolic product of estrogen. I would like to point out that under these 

 circumstances described, you have essentially a "castrate" type of pituitary. It will 

 contain a lot more luteinizing hormone, and there is evidence that it also secretes more. 

 This would account for the spleen-implanted ovaries filled with corpora lutea. I don't 

 think that one needs invoke metabolic products to account for ovaries of that appear- 

 ance, under the circumstances. 



Chairman Astwood: We might limit our discussion, now, to five or ten minutes, and then 

 go on with Dr. Rock's paper, and then take as much time as there is left for further 

 discussion. 



Dr. Carl Gemzell: Dr. Sturgis mentioned the polycystic ovary syndrome, and he also 

 mentioned the excellent studies that Dr. McArthur has done with these patients. 



We have treated a couple of cases with FSH, and in all these cases we obtained 

 ovulation much earlier than the previous three or four days, which I think confirms 

 the thought of Dr. McArthur that if there is too much delay it may induce FSH. 



Regarding the question of progesterone production in these follicles that Dr. Sturgis 

 brought up, we have no cases where the progesterone is produced in the follicles 

 before ovulation or before the factor is added. 



Dr. Ernest Knobil: I have a question to ask Dr. McArthur. What is the current status 

 of the improved method, as far as assaying LH in biological fluids is concerned? 

 Can this now be done successfully ? 



