Glucagon as a non species-specific regulator of the glycaemia in honeybee (Apis mellifica).

It is known that hormones which exist in vertebrates are very old in respect to evolution. The presence of insulin and glucagon in insects had already been suggested in the early sixties. In this study honeybees are living in an "artificial hive" in the German laboratory under exactly standardized conditions. In the French laboratory standardized conditions yielded because only emerging worker bees were used i.e. those which were just slipping from the honeycomb alveoli. It seemed of interest to introduce an in vivo model in which one animal is punctured at tergum III in order to gain 1 microliter hemolymph using a glass capillary tube . For the first time it is possible to puncture one animal three times. The main sugars in the hemolymph were silylated and determined by gas chromatography in the German resp. by nano thin layer chromatography in the French laboratory. 0-500 ng porcine glucagon resp. the same amount of purified bee glucagon were injected to the animals and the action on carbohydrates observed during 2 hours. Similar to the action of glucagon in vertebrates, carbohydrate metabolism although completely different, appears to be regulated in part in this invertebrate stem. It is concluded that glucagon may represent a key hormone for degradation of the glycogen stores.