Effect of diabetes on the rhythm of [3H]thymidine incorporation in Con-A-stimulated mice splenocytes.

The chronogram of hyperglycaemia in alloxan-induced diabetic DBA/2 mice (living under conditions standardized for light-synchronized periodicity and fed ad libitum) presented an ultradian rhythm (during spring) different from the circadian blood glucose chronogram of normal control mice. Simultaneously, the [3H]thymidine ([3H]TdR) incorporation chronogram of diabetic mouse splenocytes, stimulated or unstimulated with Concanavalin-A (Con-A), was changed and unbalanced, compared to that of normal control mice. Previous experiments showed that the [3H]TdR incorporation chronogram of stimulated or non-stimulated splenocytes of normal DBA/2 mice presented seasonal variations. They were characterized generally by an ultradian rhythm. Yet, during spring, they exhibited a circadian rhythm because one phase was advanced and superimposed on the other, the latter being typically unvarying. It seems probable that the unbalanced rhythm of [3H]TdR incorporated in diabetic mouse splenocytes, stimulated or not, was responsible for a dysfunction of that population in diabetes.