Spontaneous synthesis and release of C 16 juvenile hormone by isolated corpora allata of female locust Schistocerca gregaria and female cockroach Periplaneta americana

Abstract

Isolated pairs of corpora allata (CA) from adult females of both Schistocerca gregaria and Periplaneta americana incorporate radioactivity from [methyl- 14C] methionine into C 16 juvenile hormone (JH) when incubated for up to several hours, such that the rate of JH synthesis can be accurately determined. Analysis of the medium shows that CA from P. americana continue to release newly synthesised JH at constant rates for at least 5 hr, whereas those from S. gregaria may show a marked decrease in rate of JH release after 3 hr, particularly in the case of glands having high initial rates of synthesis and release. In both cases the rates of release of JH are strictly proportional to the rates of JH synthesis when measured over a period of 3 hr incubation, independent of the rate of synthesis. It is concluded that the spontaneous level of endocrine activity in glands from both these species can be faithfully quantified by precise radiochemical methods using the short-term incubation procedures described.