JUVENILE-HORMONE INHIBITION IN CORPORA ALLATA FROM OVARIECTOMIZED BLATTELLA-GERMANICA

Ovariectomy has been used to study the role of the ovary in endocrine homeostasis. Our studies on young virgin adults of the cockroach Blatt ella germanica (L.) (Dictyoptera, Blattellidae) show that the cytologi cal development of the corpora allata (CA) in ovariectomized females p roceeds as in intact specimens, whereas the rates of Juvenile Hormone (JH) synthesis are lower. Stimulation of the CA from ovariectomized fe males in vitro by mevalonolactone suggests that enzymatic mechanisms w hich follow mevalonate formation in the biosynthetic pathway are funct ional. The synthetic capabilities of these CA are also illustrated by the kinetics of JH production in vitro, because hormonal release incre ases with time to reach 'normal' levels after 8h of incubation, Our da ta suggest that the absence of ovaries leads to effective inhibition o f JH biosynthesis rather than to an impairment of the developmental pr ocess in the CA cells.