The effect of adipokinetic hormones on the activity of digestive enzymes |
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| Authors: | Karolina Bodláková Michaela Beňová Dalibor Kodrík |
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| Affiliation: | 1. Gymnasium ?eská, ?eské Budějovice, Czech Republic;2. Institute of Entomology, Biology Centre, CAS, ?eské Budějovice, Czech Republic;3. Faculty of Science, University of South Bohemia, ?eské Budějovice, Czech Republic |
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| Abstract: | The role of the adipokinetic hormone (AKH) in the control of protease, amylase and lipase activities is examined using the cockroach Periplaneta americana and the fruit fly Drosophila melanogaster as model species. The effects of Peram‐CAH‐I and ‐II on the activity of cockroach digestive enzymes in the gastric caeca and midgut are measured both in vivo and in vitro. The results show the activity of proteases, amylases and lipases in both parts of the gut: amylase activity is higher in the gastric caeca than in the midgut; lipase activity presents the opposite trend; and protease activity is similar in both organs. The applied hormones stimulate the activity of all digestive enzymes, although this stimulation is not uniform; AKHs affect enzymes selectively, and in some cases unequally, in the gastric caeca and midgut. No substantial differences between Peram‐CAH‐I and ‐II stimulation are recorded. The in vitro results demonstrate that AKH stimulates digestive enzyme activity directly. In agreement with the cockroach results, enzymatic activity in D. melanogaster larvae producing nonfunctional AKH is lower than that in the larvae with ectopically expressed Akh gene, where enzyme activity reaches or even exceeds that of the controls. Overall, the results demonstrate the active role of AKHs in the stimulation of digestive enzyme activity in insects. |
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| Keywords: | Adipokinetic hormone AKH amylase digestion Drosophila Akh mutant enzyme lipase midgut Periplaneta cockroach protease |
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