564 



PHYSIOLOGY OF GONADS 



Fig. 9.7. Exteriorized uteii. Tlie uteri were divided transversely from fundus to cervix. 

 The anterior half is seen deflected to the right and the posterior half to the left. A and B 

 are of the same uterus taken 13 days after exteriorization showing the "blush" and "blanch" 

 reaction of uterine contractions. It can be seen that during blanching the endometrium 

 of the cervix does not become ischemic. C. Uterus 18 days after exteriorization, showing 

 response to estrogen. Ridges formed by growth of the endometrium surrounding the in- 

 ternal OS of the cervix can be seen at the upper edge of the photograph. D, taken 83 days 

 after exteriorization, shows response produced by a series of injections of 10 ^ig. estradiol 

 and 1 mg. progesterone daily. The transverse ridge is formed by the two opposed lips of 

 endometrium derived from the area surrounding the internal os of the cervix. Growth when 

 the two hormones are given is greater than when only estrogen is injected. (From F. L. 

 Hisaw, in A Symposium on Steroid Hormones, University of Wisconsin Press, 1950.) 



The endometrium on the exposed anterior 

 and posterior halves of the uterus underwent 

 deterioration despite the best of care that 

 could be given, but that surrounding the in- 

 ternal OS of the cervix survived and retained 

 its capacity to grow, in one animal, for as 

 long as 9 months. When estrogen was given 

 this endometrium grew rapidly and within 

 a few days stood out as large elliptic lips 

 surrounding the internal os (Fig. 9.7). 

 Within 2 to 3 weeks the lips appeared to 

 reach their full size and further growth was 

 slow or absent. When estrogen treatments 

 were discontinued the endometrial lips un- 

 derwent bleeding within a few days and 

 were entirely lost. At no time were activities 

 observed that could be ascribed to coiled 

 arterioles, nor did ischemia occur during in- 

 volution previous to bleeding. It seems that 

 the response of this tissue to estrogen is like 

 that found in other experiments but the ab- 

 sence of ischemia preceding bleeding is ex- 



ceptional. The endometrium on the anterior 

 and posterior walls of uterine fistulae in- 

 variably showed ischemia for several hours 

 before active bleeding following the with- 

 drawal of estrogen. 



Markee (1940) approached the problem 

 of endometrial growth in monkeys by study- 

 ing the changes that occur in bits of endo- 

 metrial tissue transplanted to the anterior 

 chamber of the eye. Such transplants retain 

 in large measure the normal morphology of 

 endometrial tissue and changes in their cy- 

 clic growth parallel those going on simul- 

 taneously in the uterus. So much so that if 

 the animal has an ovulatory cycle, the ocu- 

 lar implants show conditions characteristic 

 of both the follicular and luteal phases, but 

 if ovulation fails to occur then the luteal 

 phase is omitted. Also, the morphologic 

 events taking place at menstruation can be 

 seen and recorded, since the transplants re- 

 gress and bleed at each menstrual period. 



