Reduction in human urinary MHPG excretion by guanethidine: urinary MHPG as index of sympathetic nervous activity.
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Blood Pressure↗
Biomedical subjects
H R Keiser
Publications and source records attributed to H R Keiser.
Effect of indomethacin and adrenocorticotrophic hormone on renal function in man: an experimental model of inappropriate antidiuresis.
The effect of prostaglandin synthesis inhibition on basal and ACTH-stimulated adrenal and renal function was investigated in normal volunteers. Data were collected during control and experimental study periods (13 days each). Adrenocorticotrophic hormone (Cosyntropin, 80 U/day) was administered i.v. on days 8 and 9 of each period. Indomethacin (150 mg/day) was given on days 5 through 13 of the experimental period. The subjects ate a constant diet containing 9 mEq of sodium, 100 mEq of potassium, and 2,500 ml of fluid daily. Indomethacin markedly inhibited urinary PGE excretion and plasma PGE concentration. The effect of ACTH alone as compared to the effect of ACTH and indomethacin showed: plasma sodium concentration, 139 +/- 1 vs. 131 +/ 3 mEg/liter (P less than 0.01, mean +/- SEM); plasma osmolality, 287 +/- 3 vs. 270 +/- 3 mOsm/liter (P less than 0.01); free water clearance, 97 +/- 66 vs. -1100 +/- 380 ml/24hr (P less than 0.01); urine volume, 2,000 +/- 60 vs. 950 +/- 200 ml/day (P less than 0.01); and urine osmolality 282 +/- 12 vs. 720 +/- 144 mOsm/liter (P less than 0.01). We conclude that the effects of ACTH and prostaglandin synthesis inhibition interact to result in inappropriate antidiuresis.
Adrenal Glands↗
Human urinary and plasma kinins: relationship to sodium-retaining steroids and plasma renin activity.
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Adrenocorticotropic Hormone↗
Relationship of human urinary and plasma kinins to sodium-retaining steroids and plasma renin activity.
In these studies we have shown that: 1. urinary kallikrein is an index of sodium-retaining steroid activity and may participate in the anti-natriuretic and kaliuretic effects of these hormones; 2. urinary kinin excretion is independent of changes in urinary kallikrein excretion; 3. levels of plasma bradykinin are highly correlated with levels of plasma renin activity probably because both respond to changes in extracellular fluid volume; and, 4. plasma bradykinin may act to antagonize angiotensin II to maintain normal blood pressure in hyper-reninemic states.
Adolescent↗
Effect of orthostatic changes on urokinase excretion.
The effects of orthostatic changes on the excretion of urokinase were studied in healthy normal volunteers. Urokinase excretion rose (average +69%) significantly (p less than .005) while urine volume fell (average-59%) significantly (p less than .001) after the subjects had been standing. There was no difference between men and women nor was there an apparent diurnal variation in urokinase excretion of recumbent subjects. A relationship between urokinase excretion and sympathetic nervous system activity is suggested.
Adult↗
Prostaglandin synthetase inhibitors in Bartter's syndrome. Effect on immunoreactive prostaglandin E excretion.
Urinary excretion of immunoreactive prostaglandin E (iPGE) was measurably increased in five of seven patients with Bartter's syndrome. The effects of indomethacin were compared with those of either aspirin or ibuprofen in four patients. Indomethacin produced notably greater suppression of urinary iPGE, greater sodium and potassium retention, greater increases in serum potassium, and decreases in plasma renin activity and in creatinine clearance than the other inhibitors. This demonstration that there is a close correlation between the suppression of urinary iPGE excretion and the extent of correction of the clinical abnormalities in Bartter's syndrome, regardless of the chemical structure of the prostaglandin synthetase inhibitor, is further evidence for the importance of prostaglandins in the pathogenesis of this syndrome.
Adolescent↗
Reduction of renal function by newer nonsteroidal anti-inflammatory drugs.
Because aspirin and indomethacin, two structurally dissimilar anti-inflammatory agents which reduce prostaglandin synthesis, both alter renal function, we studied the effect on renal function of three new nonsteroidal anti-inflammatory drugs which also reduce prostaglandin synthesis. We have shown that ibuprofen, naproxen, and fenoprofen are able to reduce renal function in patients with systemic lupus erythematosus and that such changes are associated with reduced excretion of urinary prostaglandin E (PGE)-like compounds. The changes may attenuate despite continued drug administration. These findings emphasize that renal function must be assessed with caution in patients taking these and perhaps other drugs which inhibit prostaglandin synthesis.
Adult↗
Postoperative management of patients with pheochromocytoma.
The optimal preoperative and postoperative management of patients with pheochromocytoma demands a multidisciplinary approach. We report on 5 recent patients to illustrate the large volumes of fluid needed in the early postoperative period. This large fluid requirement is owing to a combination of a change in vascular compliance after excision of a pheochromocytoma, the residual effects of specific preoperative medications (phenoxybenzamine and alpha-methyl-p-tyrosine) and the loss of fluid into the retroperitoneal compartment (third space) produced by extensive dissection. It takes 3 half-lives (36 hours) to dissipate the effects of phenoxybenzamine and alpha-methyl-p-tyrosine, which corresponds to the time in which these patients require large volumes of intravenous fluids.
Adrenal Gland Neoplasms↗
Effect of adrenal steroids on vasopressin-stimulated PGE synthesis and water flow.
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Adrenal Cortex Hormones↗
The kallikrein-kinin system in Bartter's syndrome and its response to prostaglandin synthetase inhibition.
The kallikrein-kinin system was characterized in seven patients with Bartter's syndrome on constant metabolic regimens before, during, and after treatment with prostaglandin synthetase inhibitors. Patients with Bartter's syndrome had high values for plasma bradykinin, plasma renin activity (PRA), urinary kallikrein, urinary immunoreactive prostaglandin E excretion, and urinary aldosterone; urinary kinins were subnormal and plasma prekallikrein was normal. Treatment with indomethacin or ibuprofen which decreased urinary immunoreactive prostaglandin E excretion by 67%, decreased mean PRA (patients recumbent) from 17.3+/-5.3 (S.E.M.) ng/ml per h to 3.3+/-1.1 ng/ml per h, mean plasma bradykinin (patients recumbent) from 15.4+/-4.4 ng/ml to 3.9+/-0.9 ng/ml, mean urinary kallikrein excretion from 24.8+/-3.2 tosyl-arginine-methyl ester units (TU)/day to 12.4+/-2.0 TU/day, but increased mean urinary kinin excretion from 3.8+/-1.3 mug/day to 8.5+/-2.5 mug/day. Plasma prekallikrein remained unchanged at 1.4 TU/ml. Thus, with prostaglandin synthetase inhibition, values for urinary kallikrein and kinin and plasma bradykinin returned to normal pari passu with changes in PRA, in aldosterone, and in prostaglandin E. The results suggest that, in Bartter's syndrome, prostaglandins mediate the low urinary kinins and the high plasma bradykinin, and that urinary kallikrein, which is aldosterone dependent, does not control kinin excretion. The high plasma bradykinin may be a cause of the pressor hyporesponsiveness to angiotensin II which characterizes the syndrome.
Adolescent↗
Effects of dietary potassium and race on urinary excretion of kallikrein and aldosterone in man.
Urinary excretion of kallikrein by 16 normal and 8 hypertensive subjects was studied at three levels of dietary potassium: 85 meq/day for 5 days, 185 meq/day for 7 days, and 25 meq/day for 10 days. Excretion of kallikrein varied directly with potassium intake and paralleled excretion of aldosterone in both normotensive and hypertensive subjects. Mean levels of excretion of kallikrein at 85, 185, and 25 meq intake of potassium were 10.8, 19.1, and 5.8 esterase U/day (EU/day), respectively, for the normotensive subjects and 8.8, 13.9, and 6.1 EU/day for the hypertensive subjects. Mean levels of excretion of kallikrein were significantly higher in white that in black subjects among normals and hypertensives [13.0 vs. 5.9 EU/day for normals (P less than 0.05) and 13.7 vs. 4.0 EU/day for hypertensives (P less than 0.05) on the 85 meq/day diet]. The parallel changes in excretion of kallikrein and aldosterone support the hypothesis that changes in effective levels of aldosterone induce changes in the excretion of kallikrein. Because of racial differences in excretion of kallikrein, matched groups should be used for comparisons of the kallikrein system in disease states.
Adult↗
Elevated urinary prostaglandins and the effects of aspirin on renal function in lupus erythematosus.
We studied the urinary excretion of immunoreactive prostaglandin E-like material (iPGE) and renal function in seven women with systemic lupus erythematosus to evaluate the relation between urinary iPGE and the increase in serum creatinine in patients taking aspirin. The mean pretreatment excretion of urinary iPGE in patients with lupus erythematosus, 42.7 +/- 6.4 ng/h, was significantly higher than the value of 29.0 +/- 1.9 ng/h for normal subjects (P less than 0.02). With aspirin, the urinary iPGE decreased an average of 45% (P less than 0.001). Increases in serum creatinine and blood urea nitrogen confirmed our previous clinical observations. The concomitant mean fall in creatinine clearance of 18% (P less than 0.001) was accompanied by a 14% decrease in inulin clearance (P less than 0.005); p-aminohippurate clearance fell 29% (P less than 0.005). The decline in urinary iPGE preceded the fall in creatinine clearance but was significantly correlated with it (r = 0.78; P less than 0.001). The observed changes reversed rapidly when aspirin was stopped. These data show that, in these patients with high urinary iPGE excretion, aspirin causes significant changes in renal function that may be mediated by the inhibition of prostaglandin synthesis.
Adult↗
Blood and urine histamine levels in normal and pathological states as measured by a radiochemical assay.
The utility of the enzymatic radiochemical assay of histamine in diagnosing diseases with known abnormalities in histamine production was investigated. Whole blood histamine levels were abnormal only in patients with basophilia, i.e. chronic myelocytic leukemia or polycythemia vera. Histamine was not detectable (less than 1 ng/ml) in normal plasma but was detected in plasma of some patients witheither mastocytosis or chronic myelocytic leukemia. These patients also had symptoms which could be attributed to histamine release as, for example, hyperchlorhydria and hypotension. Urinary histamine excretion was also abnormally high in these diseases compared to normal subjects (range less than 5-42 microgram/24 h, n = 31). Patients with systemic mastocytosis had higher urine values (greater than 150 microgram/24 h) than those with cutaneous mastocytosis (39-88 microgram/24 h), and the urinary histamine excretion appeared to be an index of the severity of the diseases. Studies with L-histidine loading suggest that the kidney is one possible source of urinary histamine.
Adult↗
Prostaglandin E2 biosynthesis by rabbit renomedullary interstitial cells in tissue culture. Mechanism of stimulation by angiotensin II, bradykinin, and arginine vasopressin.
The mechanism of hormone-stimulated prostaglandin E2 biosynthesis was investigated in rabbit renomedullary interstitial cells in tissue culture. Angiotensin II, bradykinin, and arginine vasopressin stimulated arachidonic acid release and subsequent prostaglandin biosynthesis. Indomethacin completely inhibited prostaglandin biosynthesis without affecting arachidonic acid release. Mepacrine, a phospholipase inhibitor, inhibited arachidonic acid release without affecting subsequent synthesis of prostaglandin E2. Our studies suggest that arachidonic acid release via hormone-activated phospholipase or acylhydrolase (or both) is the mechanism of hormone-stimulated prostaglandin E2 biosynthesis.
Angiotensin II↗
Urinary excretion of immunoreactive prostaglandin E: a circadian rhythm and the effect of posture.
The excretion of urinary immunoreactive prostaglandin E (iPGE), sodium, potassium, creatinine and volume was studied in 4 hr collections in normal women at normal activity. iPGE exhibited a circadian rhythm with an amplitude of 29% and peak excretion at 4:55 P. M. There were also significant circadian rhythms for sodium, potassium, creatinine, and volume, all peaking in late afternoon. There were no significant changes either in the total excretion or in the circadian rhythms of iPGE, potassium, or creatinine excretion when the subjects remained in bed for an entire day while the circadian rhythms of sodium and volume were significantly modified in amplitude and phase, respectively. Urinary aldosterone excretion decreased significantly when the subjects were at bed rest. iPGE excretion increased 33% when subjects were first recumbent and then erect for consecutive 4 hr period on the same day (but when subjects were erect 1 day for a 4 hr period, iPGE excretion was lower by 32% than for the same 4 hr period the preceding day when they were recumbent). These data indicate that: 1) the sympathetic nervous system and renin-angiotensin-aldosterone system do not affect the circadian rhythms of urinary iPGE, and 2) short-term experiments of prostaglandin E excretion must be designed to avoid misleading results due to the circadian rhythm.
Adult↗
Continuous measurement of tissue blood flow by laser-Doppler spectroscopy.
Laser light scattered from tissue in vivo is broadened in line width as a result of the Doppler shift produced by moving red cells in the microcirculation. A feasibility study was carried out to demonstrate use of this effect to measure and monitor tissue blood flow. Light from a helium-neon laser illuminated a 1-mm area of tissue (human skin or rat renal cortex), and the backscattered light was detected with a photomultiplier. The spectrum of the Doppler beat notes was analyzed directly with a digital spectrum analyzer, or processed by analog circuitry to yield a flow parameter based on the root-mean-square Doppler line width. This parameter was compared with 133Xe washout in the skin of volunteers subjected to UV-induced erythema and the skin of volunteers subjected to UV-induced erythema and was found to vary in an approximately linear manner with skin blood flow. The laser instrument provided continuous monitoring of blood flow fluctuations, including the pulsatile component. The instrument was used to monitor flow in the outer cortex of the rat kidney during administration of norepinephrine, angiotensin, hydralazine, dextran, dopamine, nitroprusside, and angiotensin blocked by saralasin. Dynamic and steady-state responses were consistent with known pharmacology and renal physiology, and with the assumption that vasoconstrictor angiotensin II receptors in the kidney are accessible to blood-borne inhibitors. The laser-Doppler method is a promising tool for rapid monitoring of dynamic changes in tissue perfusion.
Adult↗
Prostaglandin biosynthesis by rabbit renomedullary interstitial cells in tissue culture. Stimulation by angiotensin II, bradykinin, and arginine vasopressin.
Rabbit renomedullary interstitial cells were isolated and grown in tissue culture. These cells synthesize 0.8 ng of prostaglandin E2 (PGE2) per microgram cellular protein per hour in monolayer tissue culture; prostaglandins A2 and F2alpha (PGA2 and PGF2alpha) biosynthesis was 10 and 5% of PGE2 biosynthesis, respectively. Arachidonic acid markedly stimulated the production of PGE2 and PGF2alpha, with conversion rates of 0.24 and 0.02%/h, respectively. Angiotensin II, hyperosmolality, bradykinin, and arginine vasopressin each stimulated PGE2 biosynthesis; maximum stimulation was 20, 3.7, 3.6, and 3.2 times basal production, respectively. PGE2 biosynthesis by the renomedullary interstitial cells was inhibited by isoproterenol, potassium, nonsteroidal anti-inflammatory agents (indomethacin, naproxen, ibuprofen, suprofen, meclofenamate, and acetylsalicylic acid), mepacrine (a phospholipase inhibitor), hydrocortisone, and cortisone. The rabbit renomedullary interstitial cell in tissue culture is a model system for the study of hormonal regulation of PGE2 biosynthesis.
Angiotensin II↗
Vasopressin-stimulated prostaglandin E biosynthesis in the toad urinary bladder. Effect of water flow.
Prostaglandin E biosynthesis and its effect on water permeability were investigated in the toad urinary bladder. Arginine vasopressin (1 mU/ml) increased prostaglandin E (PGE) biosynthesis from 0.5+/-0.1 to 5.0+/-0.4 pmol/min per hemibladder (mean +/-SEM, n= 8, P less than 0.001). Maximal vasopressin-stimulated PGE biosynthesis, 6.4+/-0.2 pmol/min per hemibladder, occurred at vasopressin concentrations in excess of 3 mU/ml. Half-maximal stimulation of PGE biosynthesis occurred at a vasopressin concentration of approximately 0.7 mU/ml, whereas half-maximal stimulation of water flow occurred at a vasopressin concentration of approximately 5 mU/ml. Vasopressin-stimulated PGE biosynthesis did not depend on water flow along an osmotic gradient or upon sodium transport. Thin-layer chromatographic analysis of the lipids released from hemibladders labeled with tritium-arachidonic acid revealed that vasopressin stimulates the release of arachidonic acid from intracellular lipid stores without affecting the percentage of free arachidonic acid converted to PGE. Neither cyclic AMP nor theophylline stimulated PGE biosynthesis although they mimic arginine vasopressin (AVP) in stimulating water permeability. Biosynthesis of PGE was inhibited by mepacrine, a phospholipase inhibitor, and by agents that inhibit arachidonic acid oxygenase. The inhibition of PGE biosynthesis resulted in augmented vasopressin- and theophylline-stimulated water flow, but had no effect on cyclic AMP-stimulated water flow. We interpret these results to mean that endogenous PGE inhibits basal and vasopressin-stimulated adenylate cyclase activity. In contrast to the effects of AVP on permeability and transport, AVP stimulates PGE biosynthesis by a mechanism that does not depend on an increase in cellular cyclic AMP levels. The water permeability response of the toad urinary bladder to vasopressin is inhibited by PGE synthesized by the bladder in response to vasopressin.
Adenylyl Cyclases↗