ON THE EFFECT OF CASTRATION UPON THE GROWTH OF VARIOUS ORGANS IN THE ALBINO RAT

In the previous number of this journal (Vol. III, No. 3), Matsuba, one of the authors, published the first part of this experiment under the article "On the effect of castration upon the thyroid gland, hypophysis, thymus and adrenal in the albino rat." This paper is the second part of the same experiment, dealing with the growth of various organs and the effect of castration upon them excluding endocrine organs.The material used included 300 rats of male sex, varying from newborn to 300 days of age. The 300 rats were all raised up in our laboratory and divided into 500 lots according to litter and age. One to three rats from each lot which consisted of three to eight rats were fed as controls.All the rats excepting the controls were castrated on the 15th, 30th, 40th, 50th, 60th, 75th, 90th, 120th, and 150th day of age and killed with controls at an interval of about 30 days, extending from 60 days to 300 days of age.During the course of experiment all the rats were weighed every other day and the organs to be examined were obtained immediately after the animal were killed and then precisely weighed.The results obtained from the experiment can be summarized as follows.1. The post-natal growth of the castrated rats was in a fair agreement with that of the controls. No remarkable increase was observed in the body weight of the castrated animals; the fatty condition of the animals employed, possibly due to lack of proper feeding and management, might have caused no difference in the body weight of the castrated and the centrols.2. No effect of castration was observed in the body weight of rats, but the tail length of the castrated animals increased by 5% on an average.3. The hearts of the castrated animals develop as good as those of the controls before 180 days of age, but hereafter they showed decrease in their development. A decrease has also been found in the growth of hearts of animals castrated in younger age than those operated in advanced age.4. The weight of kidneys was less by 20-30% in the castrated than in the controls. In the weight of liver no effect of castration was observed. The spleen of the operated was all heavier than that of the control during a certain course of time after castration, but in the operated animals a decrease was found in its weight after 200 days of age.5. The effect of castration upon the length of long bones was quite remarkable; they have been found especially shorter in the animals castrated before 60 days of age. As in the case of the length, the weight of the long bones was also much less in the animals operaied before 60 days of age.6. The better was the deposit of calcium in the bone, the later the castration was performed. As regards the P and Mg contents in the bone no difference has been constated between the castrated and the controls.7. The resistance of long bones against the artificial fracture seemed to decrease due to castration. The femor was weaker in the animals operated after 60 days of age and the tibia in those castrated before the age mentioned.8, The castrated animals were generally stronger in pulling weight. The inferiority of the pulling power in the controls may probably due to their unrestless behaviour.