Effect of the duration of streptozotocin-induced diabetes on turnover of central biogenic amines in mice.

The relationship between central catecholaminergic and serotonergic neurons and the development of streptozotocin-induced diabetic mice was examined over periods of 3, 14, 50 and 100 days. The accumulation of 3,4-dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP) were measured after central decarboxylase activity was inhibited by m-hydroxybenzylhydrazine (NSD-1015). Results indicated that DOPA accumulation in the hypothalamus was not altered during the entire time course of the experiment. On the other hand, DOPA accumulation in the striatum was decreased in 50- and 100-day diabetic mice. The DOPA levels in the pons medulla were not increased until the mice had been diabetic for 100 days. The accumulation of 5-HTP was decreased in the hypothalamus of 14-day diabetic mice and was also present at 50 and 100 days, that in the striatum and pons medulla was not decreased until the mice had been diabetic for 50 days and persisted to 100 days in the striatum. These data showed that both DOPA and 5-HTP accumulation in the striatum and pons medulla were changed only in long-term diabetic mice and suggested that changes in catecholamine and serotonin turn-over rates are not generalized, but restricted only to some particular brain regions and time courses.