The adrenalin index as used in this paper means the amount of adrenalin in milligrams per gram of gland. As in our hands the chemical colorimetric method has proved more accurate, these values rather than the physiological values will be given in the final analysis. The two adrenal glands in the same individual as a rule contain about the same amount of adrenalin per gram, but variations of 10 to 20 per cent. are not unusual.
Normal dogs show an index which may vary from 1.2 to 1.8 milligrams. The dogs were killed by short ether anesthesia and bleeding from the carotid.
Normal human beings, dying from trauma, rupture of aneurysm, etc., show an index of 0.35 to 0.50 of a milligram, when autopsy takes place a few hours after death. Deterioration of uncut glands or of a gland hash kept on ice in the dark is not rapid and rarely exceeds 10 per cent. in twenty-four hours.
Acute intoxication in dogs shows a low adrenalin index, especially the intoxication associated with intestinal obstruction and the closed intestinal loop. Intravenous injection of the poison found in closed duodenal loops sufficient to cause fatal shock causes a great drop in the adrenalin index, at times to one fourth normal or even lower.
After recovery from a sublethal toxic dose the adrenalin index may rise rapidly to a point considerably above normal. The same may hold for recovery after chloroform poisoning.
Anesthesia by chloroform or ether causes a drop in the adrenalin index depending upon the length of anesthesia and probably in part on the depth of anesthesia.
Liver poisons (chloroform, phosphorus, hydrazine) cause a drop in the adrenal index to a low level, perhaps one half normal in acute cases.
Pancreas extirpation with prolonged glycosuria and death produces a great drop in the adrenalin index (cat). There is evidence that this may hold in some cases of human diabetes.
In man disease of one adrenal (tuberculosis) may be associated with an adrenalin index of double the normal value in the intact adrenal.
Pernicious anemia is the only disease so far found to present an abnormally high adrenalin index, and the single case shows an index at least twice normal. This is of interest especially in relation to the views recently put forward to indicate that the spleen and adrenal may be concerned in the lipoid metabolism which is thought to be profoundly disturbed in this disease.
Secondary anemia due to repeated hemorrhage or the intoxication of cancer or tuberculosis causes a fall in the adrenalin index. Cachexia due to neoplasm or tuberculosis may cause a marked fall in the adrenalin index, perhaps to less than one half of normal.
Acute infections (typhoid fever), septicemia, peritonitis, and similar conditions may be associated with a normal adrenalin index or one somewhat below normal.
Diseases of the kidneys, heart, or blood vessels associated with elevated blood pressure show no constant variation in the adrenalin index, which may be normal or slightly subnormal.