Comparison of adrenaline-induced hyper- and hypoglycaemia by histological and biochemical investigation.

Chronic treatment of rats by subcutaneously implanted A-depot capsules lead through a ca. 12 h hyperglycaemia to hypoglycaemia at 18 h p.o. SDH and G-6-Phase activities in the liver were compared during hyper- and hypoglycaemia using both histochemical and biochemical methods. The results show high triglyceride-contents, lack of glycogen and high G-6-Pase activities in the livers of animals during both hyper- and hypoglycaemia. Striking differences were found concerning SDH-activities: While biochemical measurements show enhanced activities during hyperglycaemia, hypoglycaemic values remain in the "normal" range. Nevertheless histochemical investigations show an amazing re-distribution of SDH-activities from the periportal areas towards the lobule centre. Therefore we think, that biochemical and histochemical methods should be combined to unveil such pseudonormalities. Further, this re-distribution shows the ability of the liver to cope with damage by shifting important processes away from fat-infiltrated areas.

Evidence for adrenalin secretion regardless of high extraglandular levels.

Chronic adrenalin administration (4 mg/18 hrs) by means of a subcutaneous depot capsule leads to hypoglycaemia and adrenalin depletion of the suprarenal gland within 18 hrs. Stimultaneous application of glucose prevents hypoglycemia as well as adrenalin depletion. By injection of 3H-labelled tyrosine 10, 20 or 30 min before killing and subsequent detection of the quantity of labelled tyrosine and adrenalin in the sera by mixing them with a standard solution containing considerable amounts of unlabelled tyrosine and adrenalin, and by passing them through a Sephadex G-10 column and finally detecting the radioactivity of the fractions in a liquid scintillation-counter, we could prove that during the stage of hypoglycaemia an enhanced adrenalin synthesis and secretion did take place regardless of a high extraglandular level. In animals treated with adrenalin and glucose, NaCl solution or alpha-methyl-tyrosine methylester-HCl no increased resp. no turnover at all could be seen. Therefore, we conclude that there is not only a lack of a direct negative feedback system between adrenalin synthesis, secretion and extraglandular level but also that the enhanced synthesis of adrenalin that can take place in spite of a high serum level can initiate a fatel circulus vitiosus.