Age and endocrine effects on fat body metabolite composition in adult male Blaberus discoidalis cockroaches

Abstract

AbstractEndocrine‐and age‐related changes in metabolite contents were used as a measure of fat body development and function in adult male Blaberus discoidalis cockroaches. Fat body dry weight, protein, glycogen, and lipid levels coordinately decreased at days two to three of adult life, increased at day four, then declined to lower stable levels by days six to seven. The metabolite contents remained stable from days seven through ten and were still at this level on day 30. Long‐term endocrine deficiencies resulting from corpora cardiaca‐allata extirpation did not change the amounts of metabolites present at 30 days of age. The fat body DNA content remained constant regardless of age or endocrine balance. Unlike other metabolites, the RNA content increased to twice its original level during the first six days of adult life and was unaffected by either age or endocrine balance thereafter. The findings suggest that the adult fat body changes from a storage function at the time of the nymphal‐adult molt to a biosynthetic function by day six. The transition is independent of endocrine control by the corpora cardiaca‐allata complex.