Changes in the activities of general esterase, L-alanine:2-oxoglutarate aminotransferase (GPT), L-aspartate:2-oxoglutarate aminotransferase (GOT), acid and alkaline phosphatase after allatectomy, brain-cauterization and juvenoid treatment have been studied. It has been shown that allatectomy reduces the GPT, GOT, general esterase and acid phosphatase activity in all tissues from both sexes and alkaline phosphatase activity in all the cases excepting the testis. Treatment with juvenoid in allatectomized insects reverses the effects of allatectomy. Both allatectomy and brain-cauterization cause the drastic decrease of all the enzymes in both sexes. The physiological significance of these findings has been discussed in this paper.
