568 



PHYSIOLOGY OF GONADS 



Fig. 9.10. Uteru.s of a castrated monkey which 

 was given 1 mg. progesteione (lail>' for 18 days 

 following an estrogen treatment. The uterus was 

 opened as described for Figure 9.9, and the injec- 

 tions of progesterone continued for 20 days. (From 

 F. L. Hisaw, in A Syiyiposium on Steroid Hor- 

 mones, University of Wisconsin Press, 1950.) 



through the opening of the fistula. Within a 

 few days tongue-like processes of endome- 

 trial tissue are thrust out of the opening 

 with each uterine contraction and are en- 

 tirely or i^artially withdrawn at each re- 

 laxation. 



Such outgrowths are difficult to protect 

 from mechanical injury and consequent tis- 

 sue loss so it is not possible to determine ac- 

 curately how much endometrium is pro- 

 duced in a given time. In one experiment an 

 animal was kept on 10 fxg. estradiol and 2 

 mg. progesterone daily for 98 days and it 

 was found that the endometrium continued 

 to grow, but the rate seemed considerably 

 slow^er toward the conclusion of the treat- 

 ment than at the beginning. How long an 

 endometrium would continue to grow under 

 these conditions was not determined, but it 

 is obvious that much more endometrial tis- 

 sue was produced by the treatment than is 

 ever found at one time in the uterus of a 

 monkey during a normal menstrual cycle. 

 This takes on added significance when it is 

 compared with the endometrial response in 

 the intact uterus of an animal given the 

 same dosage of estrogen and progesterone 

 for a similar length of time. 



The progestational development of the 

 endometrium, when both hormones are 

 given, passes through the same stages as 

 those following the injection of only proges- 

 terone; i.e., presecretory swelling of the 

 glandular epitlielium, active secretion, and 



secretory exhaustion. The endometrium, 

 however, is considerably thicker than when 

 a comparable dose of progesterone is given 

 alone, and secretory exhaustion may not be 

 so pronounced by the 30th day (Fig. 9.11). 

 The glandular epithelium in the necks of 

 the glands may be reduced to a thin mem- 

 brane scarcely thicker than the nuclei 

 whereas some secretion is usually present in 

 the dilated basal parts of the glands. Also 

 dilation of the glands in the basalis is 

 more pronounced following a 30-day estro- 

 gen-])rogesterone treatment than when the 

 same amount of progesterone is given sepa- 

 rately. 



Secretory exhaustion appears to be the 

 initial indication of an involutionary proc- 

 ess that ensues when an estrogen-progester- 

 one treatment is continued for a long time 

 (Hisaw, 1950). When a combination of the 

 two hormones, known to be capable of pro- 

 ducing a large uterus with a thick, fully de- 

 velojied, progestational endometrium within 

 al)out 20 days, is given for 100 days, an 

 astonishingly different endometrium results 

 (Fig. 9.12). It is thin, the stroma is dense 

 and the narrow straight glands are reduced 

 to cords of cells in the basal area. The con- 

 dition is one suggesting inactivity and at- 

 rophy. 



When such dosages of estrogen and i)ro- 

 gesterone are given to castrated monkeys 

 for 200 days or a year further changes in 

 the endometrium occur. By 200 days the 

 epithelium of the surface mucosa and glands 



Fk;. 9.11, .\ late i)r()ges1ati()iial condition pro- 

 duced in tlie endometrium of a castrated monkey 

 by giving 10 (ig. estradiol daily for 18 days followed 

 by 10 /xg. estradiol and 2 mg. progesterone daily 

 for 31 davs. 



