Patterns and Control of Neurosecretion for the Cytochromogenic Hormone in Blaberus Discoidalis Cockroaches

1. Corpora cardiaca (CC) from immature and adult Blaberus discoidalis Serville of both sexes contained approximately equal amounts of activity for the cytochromogenic hormone (CGH), a neurohormone which stimulates cytohaem synthesis in fat body mitochondria on day 4 of adult life. 2. CGH activity remained at a constant level in the CC of males during days 0 and 1 of adult life, decreased during days 2 and 3, and then returned to the original level by day 4. Female CC followed a similar pattern except that the period of low CGH activity occurred 1 day later. 3. Variations in early adult feeding patterns or in daily photoperiod did not change the secretory pattern of CGH. However, injections of juvenile hormone III stimulated a precocious release of CGH on days 0—1. Thus, CGH and juvenile hormone may function in this insect as a coordinated endocrine sequence directing metabolic maturation of the fat body during early adult life.