Recent advances in endocrinology / by A.T. Cameron.

  • Alexander Thomas Cameron
Date:
1936
Catalogue details

Licence: In copyright

Credit: Recent advances in endocrinology / by A.T. Cameron. Source: Wellcome Collection.

    445/498 page 425
    conclusive, evidence that it is the sole secretory excitant present in such extracts, so that “ gastrin ” is probably histamine (30). Brown and Smith (4) have found a histamine-like substance in the gastric juice. Babkin has shown that injection of histamine produces selective stimulation of the parietal cells of the gastric mucosa and in addition an inhibitive action on the “ vagal ” phase of gastric secretion (3, 2). Evidence is accumulating that histamine should be classed as an endocrine principle. Cholecystokinin. Ivy found by cross-circulation experiments that when acid is injected into the duodenum, something passes into the blood which causes the gall-bladder to contract. He claims (20) to have prepared an extract from the upper intestinal mucosa free from secretin, which when injected into dogs, cats, or man (but not rabbits), causes eontraction and evacuation of the gall-bladder. He considers that an endocrine prineiple is involved, which he terms cholecystokinin. Still has obtained similar results (34). (Cf. also 37, 18.) The Insulmotropic Principle of the Duodenum. Heller (17) showed that when extracts of duodenal mucosa were injected into normal rabbits just prior to injection of a definite amount of glucose solution, the degree of hyperglycaemia was less than would be produced by the glucose alone. This could not be attributed to secretin, which possesses no hypoglycaemic action (35). Laughton and Macallum prepared an extract from the duodenal mucosa freed from protein and peptone, and still showing the activity described by Heller (24). This extract, when injected into depancreatized dogs, was inactive. This suggested that the effect is produced through increased output of insulin. A more concentrated extract was made by extracting a desiccated preparation of duodenal mucosa with acid alcohol, evaporating the extract, and extracting the residue with hydro¬ chloric acid ; calcium phosphate was added to the acid extract and the solution adjusted to pH 7-8 to 8, The precipitated calcium phosphate carried down the active principle, and was dried and desiccated for use. Laughton and Macallum state that this preparation has no hypoglycaemic action on normal animals, but controls experi¬ mental hyperglycaemia in them. It has no effect on the hyper¬ glycaemia in totally depancreatized dogs, but lessens that follow¬ ing the administration of glucose to partially depancreatized animals. Good results have been reported following the clinical use of this extract, given orally, in diabetes mellitus (9). La Barre and his colleagues (23) have proceeded from the observation of Freud and Saadi-Nazin (1926) that the intra- duodenal injection of dilute hydrochloric acid provoked both a
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