糖尿病の原因に関する研究 : 累代アロキサン処置による高血糖のパターンについて

The work was designed with the purpose of groping for origins of diabetes mellitus. Change of the blood sugar level was pursued in hybrid mice of the CF#1 strain that were successively given a diabetogenic agent extending over five generations. In each generation, alloxan of 50mg per kg body weight was injected intravenously to matured virgin mice. The alloxanized female mice were mated with intact male mice of the same strain. Blood sugar in pregnant mice was determined on the fifth day of gestation, and that in the offspring, on the 90th day after birth. Mean of blood sugar levels following the alloxan injection rose above 200mg percent in each generation, but, in the offspring, levels were distributed around the normal. It was found that the average of blood sugar levels in offsprings born to mothers with hyperglycemia above 200mg percent was higher than that in offsprings from mothers showing blood sugar levels under 200mg percent. Regression coefficients of correlations between blood sugar levels of diabetic mothers and of their offsprings increased by degrees with going through five generations, but, on the other hand, no correlationship was found between blood sugar levels of grandmother mice and of their grandchildren. It appeared striking that a negative correlation existed between blood sugar levels before alloxan injection in mice of the fourth generation and blood sugar levels of their mothers in the third generation. After the alloxan injection in the fourth generation, correlation-ship became reversed. From the above-mentioned, the author infers that a fetus of a diabetic mother may be compelled hyperinsulinism in order to dispose hyperglycemia from the mother. Consequently, a tendency of overcompensation of the pancreatic beta-cells in the fetus may remain for a short period of time even after birth. However, as the necessary condition has already been extinguished, the pancreatic function may fall before long. Repetition of these phanomena in every generation may lead to an increased receptivity against a diabetogenic agent. In this connection, it would be important to realize that no correlaticn was seen between blood sugar levels of grandmother-and grandchild-animals. Excepting the genetic mechanism, therefore, intra-uterine environment seems to play a considerable role in the causation of diabetes mellitus.