Variations in epidermal cyclic Nucleotide-dependent protein kinase activity during moult cycle of the crayfish Orconectes limosus and hormonal control of kinase activity by 20-hydroxyecdysone

Abstract

1. 1. In correlation to changes in ecdysone hemolymph titers during moulting of the crayfish high kinase activity is observed in the moult stages D 0− D 2 3 and in postmoult stage B. 2. 2. Both basal (measured in the absence of cyclic nucleotides) and total (in the presence of cyclic nucleotides) protein kinase activity were enhanced, probably caused by an increase in tissue Levels of cAMP and cGMP and furthermore by the disapperance of a kinase inhibirory protein. 3. 3. Injection of 20-hydroxyecdysone into intermoult animals increased integumental kinase activity in a time- and dose-dependent manner, maximal activity occurring after 5 hr at a dose of 1 μg/g fresh weight. 4. 4. In vitro incubation of an integumental extract with 20-hydroxyecdysone showed no enhancement of cAMP and cGMP levels in the tissues.