The action of extracts of the pituitary body / by H.H. Dale.

  • Dale, Henry Hallett, 1875-1968.
Date:
1909
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: The action of extracts of the pituitary body / by H.H. Dale. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    can also be studied in tig. 1. It will be seen that, immediately after the injection, it becomes slightly slower and considerably more vigorous: later, with persistent retardation, it becomes weaker than before the injection. Similar effects, in the same order, have been previously described by Hedbom (17) and by Cleghorn (18). It is difficult, however, to decide how far these changes in ventricular activity are due to primary action on the cardiac muscle, how far to reduction of the oxygen supply by coronary constriction. Neither effect is modified by previous atropinisation, so that there can be no question of the peripheral vagus-mechanism being concerned. There is further, in the case of the effect on the heart-beat, as in that of the coronary constriction, no resemblance whatever to the effect of accelerator nerves or of adrenaline. The safest conclusion is to regard the action on the coronary arteries as certainly a primary effect of the extract, that on the heart-beat as probably in part due to direct effect on the heart-muscle, and in part secondary to the altered rate of coronary perfusion. It should be noted, in this connection, that under conditions of natural circulation, in which the effect of coronary constriction would be antagonised by the great rise of systemic pressure, the secondary weakening of the beat is not usually observed. The renal arteries. Schafer with Magnus (19), and later with Herring (5), found that the kidney expanded when pituitary extfact was injected intravenously. It was of interest, therefore, to examine the effect of pituitary extract on the rate of perfusion through the renal vessels. The perfusion was made with oxygenated Ringer’s solution under constant pressure, as for the isolated heart, the outflow from the renal veins being measured by the drop-counter. The kidneys used were those of cats and dogs. Both kidneys of the cat were perfused, the cannulae being inserted into segments of aorta and vena cava. From the dog one kidney was used, with cannulae in the renal artery and vein. The pituitary extract was added by injection into the circulating Ringer’s fluid. The following results were obtained: — Rate op Outflow in Drops pf,r Injection of Pituitary Extract 20 seconds Experimenl I.—Oat. 5 minims Before injection 34 After injection 20 Experiment II.—Cat. 1st. 5 minims 39 27 2nd. 10 minims 29 31 Experiment III.—Dog. 1st. 5 minims 24 20
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