The Antagonism between Juvenile Hormone and Ecdysone

Abstract

The aim of this paper is to discuss the following three questions: 1) is there an antagonism between juvenile hormone (JH) and ecdysone (Ec); 2) if so, what is the nature of the antagonism; 3) what is its role in insect development? However, it is not the aim of this paper to disprove the notions of those people (Doane, 1973; Laufer and Calvet, 1972; Wyatt, 1972; Willis, 1974) who use other terms to describe the interaction between JH and Ec. We emphasize this point for three reasons: 1) whether or not one designates the effect of JH in relation to that of Ec “antagonistic”, “modificatory” or “in concert” is, in our opinion, mainly a matter of semantics; 2) we have never claimed that antagonism is the only mode of JH-Ec interaction as we have always agreed that the JH-Ec antagonism is not strict (Lezzi and Frigg, 1971) because there are conditions under which JH does not antagonize the effect of ecdysone (Lezzi and Gilbert, 1969); 3) we ourselves shall present some evidence that JH and Ec are not likely to bind to each other or to a common receptor. Thus, the interaction between JH and Ec is not an antagonism in the strict molecular or pharmacological sense. However, in a general sense we may speak of an antagonism whenever one hormone interferes with a step previous or subsequent to the interaction of another hormone with a receptor.