Inhibition of adrenalin depletion in hypoglycaemic rats following permanent adrenalin application by depot capsule.

Chronic treatment of rats with adrenalin by means of a subcutaneous depot capsule (cont. 40 mg dry adrenalin/HCl, Merck, ca. 10 mg ascorbic acid and ca. 0.4 ml 0.9% NaCl, and sealed with a dialysis membrane to provide constant adrenalin output) leads after a primary hyperglycaemic phase to hypoglycaemia. At the onset of hypoglycaemia the adrenalin contents of the suprarenal glands decrease to levels of about one third of their normal state. Simultaneous glucose infusions by intraperitoneal depot capsules prevent hypoglycaemia as well as adrenalin depletion. The fact that adrenalin depletion does not always correspond with blood sugar levels below 80 mg/dl and that this depletion could be prevented by glucose infusions altogether seems to provide a strong hint that the mentioned depletion is due to hypersecretion and not to the blocking of adrenalin synthesis. If is true, then there must be no direct negative feed-back system between adrenalin secretion and its extraglandular level.