HYPERTREHALOSEMIC HORMONES INCREASE THE CONCENTRATION OF FREE FATTY-ACIDS IN TROPHOCYTES OF THE COCKROACH (PERIPLANETA-AMERICANA) FAT-BODY

The effect of the hypertrehalosemic hormones, HTH-I and HTH-II, on fre e fatty acid levels in trophocytes prepared from Periplaneta americana fat body by collagenase treatment was investigated. Following a chall enge from either of the hormones the content of palmitic, stearic, ole ic, and linoleic acid in the trophopcytes increased. The increase in f ree fatty acid concentration due to the action of the synthetic hormon es was generally in the range of 40-95% for each of the four fatty aci ds. Crude corpus cardiacum extract containing the native hormone also had a stimulatory effect, which was comparable to that of the syntheti c hormones. In the intact insect the injection of synthetic hormone wa s followed by an increase in the level of the four fatty acids in the hemolymph. HTH-II was more potent in this respect than HTH-I. Free fat ty acids in the mycetocytes and urate cells did not respond to either of the synthetic hormones. (C) 1997 Elsevier Science Inc.