The changes in urinary output caused by administration of the extract of the pituitarybody (posterior lobe) have hitherto been investigated by many workers, and some have reported diuretic, some antidiuretic results, and others both.
Rabbits and toads (Bufo formosus) were chiefly used, in a narcotic or non-narcotic state (urethane or chloralose). Beside commercial preparations (Pituitrin, Hypophysin and Pituglandol), a special preparation was procured by Ishikawa of the Imperial Hygienic Laboratory, (Tokyo), which, containing no preservative, was injected subcutaneously or intravenously. The amount of urine was counted in drops per minute from the cannulae inserted in the ureter on both sides.
In experiments on rabbits and toads, the changes in urinary output after the administration of pituitary substances, showed four stages in the following intervals of time: 1) antidiuretic (2-30 minutes), 2) diuretic (30-60 minutes), 3) antidiuretic(2-12 hours), 4) diuretic (20-180 minutes). Differences in species and individuals of laboratory animals as well as the conditions under which the experiments were carried out (e. g., administration of water per os or, immersion in water, or narcotization ect.) had influences only on the duration and strength each stage, but never affected the order of appearance of the above-mentioned four stages. In order to observe each stage clearly, it is recommended to give water per os before the injection. Narcosis makes the third stage (antidiuretic) appear rather obscure. In the experiments eliminating the bladder and ureters form the urinary passage, the author confirmed that the first stage (antidiuretic) was not due to the contractions of bladder or ureters; but the direct observation of the living frog (Rana nigromaculata) and the toad's kidney revealed, after the injection of pituitary substances cessation or slowing down of glomerular circulation. This is due to the contraction of afferent and efferent vessels of glomeruli (chiefly afferent vessels), and is to be regarded as the important factor in the important factor in the diminuition of urine in the first stage (antidiuretic).
Blood components (red blood cells, heamoglobin and Cl.) and Cl-concentration in urine were measured at each stage of the urinary changes and the following results were obtained. “Primäre Bluteindickung” appeared, but was practically negligible. For two to five hours after the injection hydraemia continued, reaching its maximum in the third stage and returning to its normal level before the commencement of the fourth stage (diuretic). As usual, the highest point of the second stage (diuretic) preceded the maximum of hydraemia; i. e., hydraemia and diuresis did not go parallel. The antidiuretic phenomenon of the third stage can be explained as result of a higher “watr-threshold” of glomerular membrane. The Cl-concentration in the blood fluctuated little throughout the four stages. On the contrary, the Cl-concentration in urine showed a marked increase in the second stage (diuretic).
Next, observing the exposed heart (in situ) in a rabbit, the slowing down of heart-beats and the stagnation of the blood in the right auricule (as well as in the pulmonary system) during the first stage (antidiuretic) was confirmed. Intravenous injection of the preparation of pituitary posterior lobe caused a great rise in carotid-pressure: this was preceded by a fall, sometimes a considerable one. This rise of carotid-pressure always reached its highest point before the commencement of the second stage (diuretic). Although therefore, it cannot be simply concluded that the rise of carotid-pressure is the chief moment of the second stage (diuretic), it certainly produce advantageous influences on the diuresis. At the time of high carotid-pressure so-called “vagistimulation” occured, but almost disappeared by cutting of both vagi. The peripheral venous blood-pressure at first showed a slight

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