SUMMARY
Fruit flies have eight identified Drosophila insulin-like peptides (DILPs) involved in regulation of carbohydrate concentrations in hemolymph as well as accumulation of storage metabolites. In the present study, we investigated diet-dependent roles of DILPs encoded by genes dilp1–5, and dilp7 in regulation of insect appetite, food choice, accumulation of triglycerides, glycogen, glucose, and trehalose in fruit fly body and carbohydrates in hemolymph. We found that dilp2 gene predominantly influences body glycogen level, dilp3 – trehalose level in hemolymph, while dilp5 and dilp7 affect triglyceride level. Fruit fly appetite was found to be regulated by dilp3 and dilp7 genes. Our data contribute to the understanding of Drosophila as a model for further studies of metabolic diseases and may serve as a guide for uncovering the evolution of metabolic regulatory pathways.
HIGHLIGHTS Different Drosophila insulin-like peptides play distinctive roles in metabolism, physiology and appetite regulation.
Lack of Dilp2 and Dilp5 abrogates glycogen accumulation on high carbohydrate diets
Lack of Dilp3 leads to build-up of trehalose in haemolymph on high-carbohydrate-low-protein diets
Lack of Dilp3 and Dilp7 leads to increased consumption of protein on low-carbohydrate-high-protein diets
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