WOODHEAD, A.P.; THOMPSON, M.E.; HASS, J.K.; STAY, B.; University of Iowa; University of Iowa; University of Iowa; University of Iowa: Allatostatin in ovaries of the cockroach Diploptera punctata

Allatostatins (ASTs), a family of peptides of widespread occurrence in invertebrates, were first isolated from brains of D. punctata as an inhibitor of juvenile hormone production by the corpora allata. Since then they have been found to have diverse localizations, including nerves of gut muscle, hemolymph and blood cells, and functions, including neuromodulation and myomodulation. In the present study a stage- specific and localized occurrence of allatostatin has been demonstrated in the ovaries of adult females during the 7 days of the first vitellogenic cycle. ELISAs, using antibody against one of the allatostatins (Dippu AST 7), showed that the content increased from 6 fmol/ovary pair on day 3 to 120 fmol/ovary pair on day 7 with the largest increase (3.4 fold) between days 6 and 7 when chorion is formed. AST was released into medium in which ovaries were incubated only during chorionogenesis. Immunocytochemistry demonstrated that AST occurs in the basal oocytes. It is distributed in the cortical cytoplasm of the entire oocyte during vitellogenesis and early chorionogenesis and at the anterior end of the oocyte where the micropyle is formed in late stages of chorionogenesis. During ovulation it appears on the surface of the chorion and in the lumen of the oviduct. Ovarian allatostatin may serve a myomodulatory function.