Susceptiblity of the Reproductive Organs to Human Chorionic Gonadotropin in Various Strains of Mice

Investigations were made on the susceptibility of the reproductive organs of inbred strain mice subcutaneously injected with human Chorionic gonadotopin (HCG) . The doses of HCG given per mouse were 1.5, 3.0 and 6.0 I.U. respectively. Immature female dd mice and 9 strains of inbred mice were employed. Each of them had a specificity in physiological features. The results are summerized as follows:<BR>1) Body weight was found to be significantly different among the strains, both at time of injection (21 days) and autopsy (25 days) . However, no significant difference was observed with regard to doses of HCG.<BR>2) When the vaginal opening was tested at time of injection, a significant difference was found among the strains of mice: Such strains of mice as C3H/He, RR and CFW were positive, but the other 7 strains were negative. The rate with which the positive vaginal opening occurred was higher in the strains of C3H/He and RR than in CFW. When autopsied after the injection of saline, DDK mice were negative for this response, whereas the other 9 strains of mice were positive, varying from strong to mild. The vaginal opening response differed significantly between the mice injected with saline and those with HCG. This finding was observed in each strain. No difference in the positivity was found, among the doses of HCG injected.<BR>3) There was a significant difference in the hemorrhagic follicles and corpora lutea forming reaction among the strains of mice. A significant difference was found between AA and the following strains: DDK, C3H/He, NC and C57BL/6. On the other hand, significant differences were observed among all of the doses, except for 3.0: 6.0 I.U.<BR>4) The ovarian weight reaction differed significantly among the strains of mice and the doses of HCG. It appears that the difference in this reaction was more strongly influenced by the strain of mice than by the doses of HCG. Significant differences were recognized among all of the doses, with the exception of 3.0 : 6.0 I.U.<BR>5) As to the uterine weight reaction, a statistical difference was found in the strains of mice and the doses of HCG. The difference by doses was, however, more marked as compare with that by strains. The results of the uterine weight reaction differed from those of the ovarian weight reaction according to the doses of HCG given.<BR>6) In any strain the results of the rate of vaginal opening response and the weight of ovary and uterus of mice were not connected with the body weight.<BR>7) In any strain there were no relationship between the increase rate of the weight of ovary and uterus.<BR>8) In regard to the uterine weight reaction to HCG within a litter, the variation in dd mice was more apparent than in the 9 strains of inbred mice. The reactivity was not uniform in the litter of dd mice.<BR>9) The regression of the uterine weight reaction to HCG was significantly linear in various strains of mice. The variation ratio among the strains of mice was larger than that obtained for a single strain. The coefficient of Regression for the uterine weight reaction was linear and quodratic in C3H/He and CFW, linear and cubic in CF#1, but not in DDK, RR and NC. The coefficient of linear regression was statistically significant in AA, C57BL/6, SS and dd. This coefficient of the uterine weight reaction for AA mice was statistically higher than those for SS and dd.