HEMOLYMPH AND TISSUE TITERS OF ACHETAKININS IN THE HOUSE CRICKET ACHETA-DOMESTICUS - EFFECT OF STARVATION AND DEHYDRATION

Achetakinin-like immunoreactive material in tissues and haemolymph of adult male crickets was quantified by radioimmunoassay. Achetakinin-li ke material was found in the brain, suboesophageal ganglia and the tho racic and abdominal ganglia, but the largest amount was within the ret rocerebral complex. A Ca2+-dependent release of achetakinin-like immun oreactive material was demonstrated from retrocerebral complexes incub ated in vitro in saline containing a high concentration of K+. The con centration of achetakinin-like material in haemolymph from fed cricket s was estimated to be 2.8 nmoll(-1) and increased more than 10-fold in insects starved for 48 h without access to water. The presence of ach etakinin-like material in haemolymph suggests that these peptides are released in vivo and function as circulating neurohormones.