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THE MECHANICAL FACTORS WHICH AFFECT THE SECRETION OF URINE IN MAMMALS, AND THEIR OPERATION DURING PREGNANCY
Author(s) -
Theobald G. W.,
Verney E. B.
Publication year - 1935
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0370-2901
DOI - 10.1113/expphysiol.1935.sp000692
Subject(s) - diuresis , endocrinology , blood pressure , antidiuretic , medicine , chemistry , kidney , urine , hormone
1. No decrease in the response of the kidneys to the ingestion of water was found to follow an increase of pressure in the renal veins sufficient to cause albuminuria. 2. An increase of the ureter pressure by 5 mm. Hg over that of the atmosphere causes dilatation of the pelvis and calyces of the kidney, and a diminution in the rate of urinary secretion which is relatively greater the lower the rate of urine flow. On the other hand, if during water‐diuresis a pressure of 60 mm. Hg be applied to the ureter, the rate of urinary secretion may still be as high as one‐quarter of the normal rate at the peak of diuresis. 3. A sustained intra‐abdominal pressure between 11 and 18 mm. Hg produces no significant change in the course of water‐diuresis in the dog. 4. Determinations of the colloid osmotic pressure of the blood serum before and during water‐diuresis show no significant variations. 5. The marked effect of a change to the upright posture on water‐diuresis is only obtained after the position has been adopted for some 10 minutes, and if the subject remains motionless. 6. The effect of the upright posture on diuresis is to be explained by stagnation of the blood in the lower extremities, due to gravity and the absence of muscular contractions. The stagnation of blood leads to an increase in pressure in the capillaries and consequent loss of fluid from the circulation to the tissues. This can to a considerable extent be prevented by previous bandaging of the legs. 7. The abnormal partition of urine during the latter months of pregnancy can be adequately explained by assuming that the pressure in the veins draining the legs is increased by the weight of the pregnant uterus. The fluid lost to the tissues by day re‐enters the circulation and is excreted by night. 8. If the fluid thus lost to the tissues by day is excessive and is not presented to the kidneys for secretion by night, œdema of the tissues commencing in the lower extremities will occur. 9. We suggest that the best way of avoiding the pyelitis of pregnancy is to ensure a daily water‐diuresis during the whole course of pregnancy.