FUJIE, one of the authors, has reported previously (this Archiv, Vol. 1, No. 4 Oct. 1950) that when food reaches the stomach, production of zymogen granules always occurs in the pancreatic cells, and this takes place without any relationship to the discharge of the granules, and is an effect of direct stimulation from the stomach. The authors then took up the question of the stimuli and the conclusion was reached that the most interesting and yet possible answer was hematogenous stimulation, which is due to some hormone.
To substantiate this idea, the authors carried out the following experiments. As the first stage, food, which stroagly stimulates the function of the pancreatic cells (discharge and production of zymogen granules), was given to rats and blood then collected from each rat, and injected into other rats which were kept in a condition of hunger, in other words the pancreatic cells were in a condition of functional rest.
In the second experiment, the function of the pancreatic cells was artificially divided and only the production of zymogen granules held in an active state. For this purpose, the pylorus was ligatured and then food given. Blood was collected from these rats and injected into other rats as in the previous experiment.
According to the results of these two experiments, it was positively demonstrated that the factor which stimulates production of zymogen granules is found in blood. Therefore as the the third experiment, the authors injected an extract of the mucous membrane of pig's stomach into starved rats, and a very clear cut of zymogen granules production in the pancreatic cells was observed.
Thus the authors demonstrated that the factor in blood which stimulates production of zymogen granules is a hormone, whish is secreted from the mucous membrane of the stomach.
Whether this hormone, secreted from the mucous membrane of the stomach, is identical with gastrin of EDKINS (1906), or something entirely new, can not be determined without future research.
The results obtained here and those previously obtained by FUJIE and his collaborator show positively that 1. the secretory function of pancreatic cells can be divided into two, that is discharge and production of zymogen granules, 2. the former is initiated by a hormone, secretin, secreted from the duodenum, and 3. the latter by a hormone, secreted from the mucous membrane of the stomach.
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