A Study of the Quantitative Relationship Between Antidiuretic Hormone (Vasopressin) and the Renal Tubular Reabsorption of Water1

134

It has been observed that the saluretic agent chlorothiazide (6-chloro-7-sulfamyl-1,2,4-benzothiadiazine-1,1 dioxide) and its analogs produce alterations in the process of urinary dilution which differ from those expected from a simple increase in electrolyte excretion (1-3). Heinemann, Demartini and Laragh (2) observed in human subjects undergoing water diiuresis that the augmented electrolyte excretion resulting from the injection of chlorothiazide was associated with no increase, or a fall, in the clearance of free water. In a single experiment the authors observed no effect of the drug on the elaboration of a concentrated urine, and suggested that chlorothiazide may in part interfere with the reabsorption of electrolyte at sites in the distal convoluted tubule where urinary dilution normallv occurs. The absence of an effect on the concentrating mechanism has been confirmed by others (4).Crawford and Kennedy (3) found that the continuous administration of chlorothiazide (or hv-(lrochlorothiazide) per cent dextrose in water was infused at a constant rate of 10 to 14 ml per minute. Urine was collected by free flow through an indwelling catheter with the dog in the upright position. After at least 1 hour had been allowed for equilibration, urine specimens were collected and the rate of flow and osmolality determined. \Vchen these were stable for 3 consecutive 10-minute periods collection of "control" periods was begun. Venous blood samples were collected every 30 to 40 minutes by free flo\w through an indwelling needle into a heparinized tube.In 4 experiments, after the collection of 3 "control"periods, chlorothiazide (50 mg per kg body weight) was administered intravenously and a like amount was given by constant infusion each hour. Four 10-minute periods were then collected. The acute change in solute excret.on and free water clearance produced by the drug under these conditions was thus determined. In order to examine the relationship between Cos.g and Ci12o during water diuresis, 2.5 per cent mannitol in water was infused in 3 experiments to produce progressively increasing rates of solute excretion. The relationship was re-examined during the administration of chloro-.hiazide. The drug was administered either before the 2.5 per cent mannitol infusion was begun or after the mannitol had been infused and a high rate of solute excretion attained. In the former instance the mannitol infusion was then started in order to increase solute excretion, and in the later instance it was then stopped in order to decrease solute excretion. The effect of chlorothiazide was thus examined under conditions of both increasinog and decreasing rates of solute excretion.Thle effect of an equivalent dose of acetazolamide was examined in the same manner.Maximial hydropenia and aWtidincretc hlormiione. In order to examine the effects of chlorothiazide on urinary concentration, 11 experiments were performed on 5 trained unanesthetized mongrel female dogs. The dogs w\ere 857

Section: Resultsmentioning

confidence: 99%

The Effects of Infusions of Chlorothiazide on Urinary Dilution and Concentration in the Dog

Earley¹,

Kahn²,

Orloff³

1961

134

“…One would expect, were the membrane freely permeable to water during vasopressin administration, that superimposed osmotic diuresis would invariably result in some degree of urine hypertonicity. It is likely that: 1) permeability to water is never absent, and therefore that the rate of outward diffusion of water is dependent on intraluminal osmotic pressure even during water diuresis (11); and 2) the permeability of the tubule membrane in the distal segment varies in a graded fashion as a function of the dosage of vasopressin (12).…”

Section: Discussionmentioning

confidence: 99%

“…The studies of Hollander, Williams, Fordham, and Welt (12) posing effects, the former diminishing outward diffusion of "freed" water and the latter enhancing it. Which effect is greater will determine whether urine is hypotonic or isotonic when delivered to the segment in which water can be removed to produce hypertonicity.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Variations in Solute Excretion and Vasopressin Dosage on the Excretion on Water in the Dog

Orloff¹,

Wagner²,

Davidson³

1958

It has been known for some time that osmotic diuretics may modify the effect of vasopressin on urine concentration (1, 2). However, it has been generally assumed that urine will remain hypertonic to plasma if sufficient hormone is administered irrespective of the extent of the solute diuresis. This conclusion was based on the thesis that the major action of vasopressin is to promote the elaboration of a hypertonic urine presumably by a process involving active water reabsorption. Smith (3) and Wesson and Anslow (4), on the other hand, have suggested that vasopressin increases permeability of the tubule membrane to water in the distal segment, permitting osmotic equilibration in this area, and thereby diminishing the volume of isosmotic fluid delivered to a hypothetical concentrating site in the collecting duct.The experiments to be reported were designed to reexamine in a quantitative fashion the effect of solute excretion on the renal response to purified arginine vasopressin. The data have been interpreted in the light of present information concerning the probable mode and sites of action of the hormone. METHODS AND MATERIALExperiments were performed on trained, unanesthetized female dogs weighing approximately 20 Kg. each. Preliminary studies were performed on animals which had undergone section of the supraoptico-hypophyseal tracts and pituitary stalk. Despite persistent polyuria and polydipsia it was impossible to rule out the presence of residual antidiuretic hormone in these animals. The infusion of hypertonic saline during water diuresis resulted in a gradual decrease in free water clearance (CH20, see below), albeit at a lesser rate than in normal dogs; and further, early morning urine was invariably hypertonic to plasma. Consequently it was concluded that these preparations afforded no significant advantage over normal dogs for the purpose of these studies.All experiments were performed following a 12 to 16 hour fast. Water was allowed ad lib. when necessary. Dogs were loosely restrained and maintained in the supine position throughout the experimental procedure. Extraneous stimuli were reduced to a minimum to insure adequate suppression of antidiuretic hormone release in hydrated animals. Bladder urine was collected by means of a soft indwelling rubber catheter. At the beginning of each study the dogs were given a quantity of water by stomach tube equal to 3 per cent of their body weight. Thereafter this positive water balance was maintained by administering 2.5 per cent glucose in water intravenously at a rate sufficient to maintain plasma osmolality relatively constant. Solute diuresis was produced by intravenous administration of an isotoni'c solution of mannitol into the opposite limb.The clearance of inulin or crtatinine was used as a measure of glomerular filtration rate. Creatinine was determined by the method of Kennedy, Hilton, and Berliner (5) and inulin by the method of Walser, Davidson, and Orloff (6). Urine and plasma osmolality were determined cryoscopically using the instrument develop...

“…Within the limits of urinary collections, peak (12) from the data of Hollander, Williams, Ford-water diuresis was obtained when the plasma conham, and Welt (20) and Lauson (21). From the centration of ADH was either zero or slightly greater (Table VIII).…”

Section: Served Values Confirm the Tj Calculated By Lausonmentioning

confidence: 99%

Physiologic Studies of Antidiuretic Hormone by Its Direct Measurement in Human Plasma *

Czaczkes¹,

Kleeman²,

Koenig³

et al. 1964

153

Research on mammalian antidiuretic hormone (ADH) has been seriously limited by the lack of techniques for detection of physiological levels of ADH in blood and plasma.The bioassay of Jeffers, Livezey, and Austin (1), using the ethanol-anesthetized rat for ADH in mammalian plasma, was significantly refined by Dicker (2), who was able to detect as little as 2 uU ADH per ml of plasma. More recently, Heller and Stulc (3), using rats with exteriorized urinary bladders, could detect as little as 0.65 ,uU per ml of plasma. With this technique Heller and Stulc (4) found mean levels of 1.67 ,uU per ml of ADH in the plasma of "normally" hydrated men.The present study was undertaken to evaluate Heller's procedure and, if possible, to utilize it to study the release, turnover, and action of ADH. MethodsA. Assay method for ADH 1) Exteriorization of the urinary bladder. Female rats of the Sprague-Dawley strain, weighing 100 to 120 g, were anesthetized with ether. After shaving the skin about 1 cm above the symphysis pubis, the linea alba was incised and the peritoneum was opened. The top of the bladder was drawn out with fine forceps. The upper half of the bladder was cut off, and the edges were sutured with thin catgut (50) to the edges of the skin * Submitted for publication May 11, 1963 incision. Eight sutures were utilized, the first two being placed at the superior and inferior margins in the mid-line of the bladder. The mid-line can be identified by a fine dorsal or posterior mesentery. Care was taken not to twist the bladder during suturing. Distortion of the trigone could lead to ureteral obstruction. Four to five days after surgery the rats could be used for the assay. The same rats could be used twice at an interval of 4 to 6 days. After this period there frequently developed ascending pyelitis and pyelonephritis.2) Assay. The rats were hydrated as well as anesthetized by giving 12% ethanol in water by stomach tube. The rats were given two doses, each equal to 3% body weight, at 30-minute intervals; a third dose, given after 20 minutes, was about 2% of the body weight. The amount of ethanol given with the third dose varied according to the state of the individual animal. Some rats were completely anesthetized by the first two doses, and in this case only tap water was administered as the third dose; others were quite awake and therefore needed an additional dose of 12%o ethanol. Infrequently, in-between doses were given. Care was taken not to give larger amounts of ethanol than necessary to anesthetize the rats as this could bring on shock and even death.When anesthesia was sufficiently deep, at the longest, 10 to 15 minutes after the third dose, a little vaseline was applied around the exteriorized bladder, and the animal was laid prone on a table-like board. A small funnel that fitted through a hole in the board was put in contact with the skin around the exteriorized bladder so that the urine flowed directly through this funnel into graduated tubes that could be read to 0.05 ml. These tubes were made from 5.0-ml ...