THE GONADOTROPIC HORMONES 



interstitial tissue which gradually receded as "antihormone" 

 was produced. The experiments of Bachman (1936) indi- 

 cated that prolan might produce hypertrophy of the inter- 

 stitial stroma or non-functional corpora lutea, if injected into 

 young rabbits. Padootcheva and her colleagues (1935) be- 

 lieved that prolan is of practical value in rearing rabbits. 

 Pregnancy was successfully initiated by causing ovulation by 

 the injection of prolan after a suspension of spermatozoa had 

 been injected into the uterus. The vaginal instillation of 

 spermatazoa also was successful. The authors stated that on 

 a rabbit farm pregnancy occurred in 74 per cent of animals 

 receiving an ovulating dose of prolan, whereas the propor- 

 tion was only 30 per cent without such treatment. The in- 

 jection of prolan by various routes brings about ovulation in 

 sheep without signs of oestrus, according to Zawadowsky and 

 others (1935). They recommended the administration of 

 100-500 mouse-units and found that corpora lutea due to 

 this treatment did not interfere with expected oestrous 

 cycles.^ 



Comparisons of the dose of prolan necessary to cause 

 ovulation in pregnant and non-pregnant rabbits have been 

 made by Rowlands (1935) and are discussed on pages 69-70,^ 

 Prolan has some replacement value in pregnant rabbits which 

 have undergone hypophysectomy, as was shown by Robson 

 (1937). The same author found that, although hypophysec- 

 tomy of the rabbit is followed by a rapid loss of ovarian 

 sensitivity toward gonadotropic hormone, the injection of 

 prolan will postpone the appearance of this refractory condi- 

 tion for nearly two weeks. In hypophysectomized rabbits 



* Markee and Hinsey (1936) injected urine of pregnancy into rabbits, so that the 

 course of ovulation could be carefully stud'ed by observing the ovary through an 

 abdominal window or in the anterior chamber of the eye after transplantation. 



Holtz and Wollpert (1937) used prolan to induce the formation of luteal tissue 

 in the ovaries of guinea pigs and cats. They were interested in the uterine response 

 to epinephrine under these conditions. 



' Weinstein and Makepeace (1937) estimated that the dose of prolan causing 

 ovulation in oestrous rabbits must be doubled or trebled in pseudopregnant rabbits. 



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