Effects of rat adrenal homogenate on induction of atherosclerosis in cholesterol-fed rabbits

Virgin male Sprague-Dawley rats are resistant to atheroma formation. An adrenal homogenate from such rats delayed the increase in serum cholesterol concentrations in cholesterol-fed New Zealand white rabbits. More importantly, aortic atherosclerosis was markedly reduced when compared to a similar population fed cholesterol without adrenal homogenate for 14 weeks. The nature of the active constituent in this homogenate and its mode of action are unknown.

Ischemic cardiovascular complications concurrent with administration of captopril. A clinical note

Administration of potent vasodepressor agents such as the angiotensin converting enzyme inhibitor, captopril, may precipitate myocardial ischemic events in patients with coronary artery disease, particularly if this treatment is preceded by a discontinuation of beta-blocking drugs such as propranolol. In one case studied, a patient experienced three episodes of angina pectoris under these conditions; in another, acute anterior myocardial infarction was suspect.

Hypercalcemia associated with chronic lymphocytic leukemia

A patient with chronic lymphocytic leukemia (CLL) is described in whom hypercalcemia occurred in association with elevation of the peripheral lymphocyte count and expansion of total tumor mass. Hypercalcemia was ameliorated with the institution of chemotherapy for the leukemic process and subsequent fall in WBC count and decrease in total tumor burden; hypercalcemia recurred with relapse of the leukemic process. The serum immunoreactive parathyroid hormone (iPTH) concentration, when measured, was inappropriately elevated for the degree of hypercalcemia. The hypercalcemia would appear to be a direct consequence of the leukemia, and possibly involved secretion of a parathyroid hormone-like polypeptide by the CLL cells. Although a possible role for either an osteoclast-activating substance or prostaglandins was not excluded, they would not account for the elevated serum iPTH levels observed.

Identification and differentiation of surgically correctable hypertension due to primary aldosteronism

During a protocol study for the evaluation of patients with primary aldosteronism, a variety of diagnostic studies were employed in an attempt to identify patients with primary aldosteronism and to differentiate patients with adrenal adenoma from patients with idiopathic adrenal hyperplasia. In this study, we are able to demonstrate the utility of (1) absent postural increase in plasma aldosterone concentration, (2) adrenal scanning and (3) normalization of blood pressure with spironolactone therapy in identifying patients with primary aldosterone excess who have an adrenal adenoma, surgical removal of which results in eliminating their hypertension.

Estimating compliance with diuretic therapy: urinary hydrochlorothiazide-creatinine ratios in normal subjects

We gave 21 healthy young men 100 mg of hydrochlorothiazide daily to determine whether or not urinary detection of the drug was feasible as a measure of compliance on a standard antihypertensive regimen. All subjects took the drug daily for 6 days, after which they were divided into four groups with differing patterns of medication administration. Urine hydrochlorothiazide and creatinine measurements were obtained to validate the urinary hydrochlorothiazide-creatinine ratio (UHCR) as an accurate quantitative index of compliance. The subjects achieved a constant level of UHCR of 13 +/- 3.0 within 48 hours of hydrochlorothiazide administration. The UHCR levels decreased to 5.0 +/- 0.8 48 hours after discontinuation of the drug (p less than 0.001). UHCR values in the range of 13 +/- 6 indicate that the subject has ingested hydrochlorothiazide 24 hours previously. The UHCR is a potentially useful means of assessing compliance in hypertensive patients taking hydrochlorothiazide.

Hemodialysis-resistant hypertension: control with an orally active inhibitor of angiotensin-converting enzyme

In two patients with end stage renal disease and dialysis-resistant hypertension, the orally active inhibitor of angiotensin-converting enzyme, captopril (SQ14,225; 2-D-methyl-3-mercaptopropranoyl-L-proline, dramatically lowered blood pressure both before and during dialysis. This agent holds promise as an alternate to bilateral nephrectomy in such patients.

Effects of metoclopramide and bromocriptine on the renin-angiotensin-aldosterone system in man. Dopaminergic control of aldosterone

This study was designed to investigate the possible role of dopaminergic mechanisms in the control of the renin-angiotensin-aldosterone system in normal man. Six normal male subjects in metabolic balance at 150 meq sodium, 60 meq potassium constant intake received the specific dopamine antagonist, metoclopramide, 10 mg i.v. or placebo followed by angiotensin II infusion 1 h later on 2 consecutive days. Metoclopramide increased plasma aldosterone concentration from 8.2+/-2.2 to 21.0+/-3.3 ng/100 ml (P < 0.005) and plasma prolactin concentration from 18.0+/-4.0 to 91.7+/-4.0 ng/ml (P < 0.001) within 15 min of its administration. At 1 h, plasma aldosterone and prolactin concentrations remained elevated at 16.8+/-2.1 ng/100 ml (P < 0.01) and 86.8+/-15.9 ng/ml (P < 0.005), respectively. Angiotensin II at 2, 4, and 6 pmol/kg per min further increased plasma aldosterone concentration to 27.2+/-3.4, 31.9+/-5.7, and 36.0+/-6.7 ng/100 ml (P < 0.02), respectively. Placebo did not alter plasma aldosterone or prolactin concentrations, but angiotensin II increased plasma aldosterone concentration to 13.7+/-2.4, 19.0+/-1.9, and 23.3+/-3.2 ng/100 ml (P < 0.005). The increment of plasma aldosterone concentration in response to angiotensin II was similar after metoclopramide or placebo. The six subjects also received the dopamine agonist, bromocriptine, 2.5 mg or placebo at 6 p.m., midnight, and 6 a.m. followed by angiotensin II infusion on 2 consecutive d. Bromocriptine suppressed prolactin to <3 ng/ml. After placebo, plasma aldosterone concentration increased from 5.2+/-1.4 to 12.3+/-1.7, 17.2+/-2.2, and 21.8+/-3.5 ng/100 ml (P < 0.01) and after bromocriptine from 7.2+/-1.0 to 14.7+/-3.0, 19.8+/-3.2, and 23.4+/-1.6 ng/100 ml (P < 0.001) with each respective angiotensin II dose. No difference in the response to angiotensin II after bromocriptine or placebo was observed. Plasma renin activity, free 11-hydroxycorticoid concentration, and serum potassium concentration were unchanged by metoclopramide or bromocriptine. The results suggest that aldosterone production is under maximum tonic dopaminergic inhibition which can be overridden with stimulation by angiotensin II in normal man.

Activity of [des-aspartyl1]-angiotensin II in primary aldosteronism

This study describes the effects of [des-Aspartyl(1)]-angiotensin II ([des-Asp]-AII) on blood pressure and aldosterone production in patients with primary aldosteronism due to aldosterone-producing adrenal adenoma (APA) and idiopathic adrenal hyperplasia (IHA), and in normotensive control subjects. 10 patients with primary aldosteronism, 7 with APA and 3 with IHA, and 6 normotensive control subjects were placed on a constant 150-meq sodium diet for 4 days. [des-Asp]-AII was infused for 30 min at 6, 12, and 18 pmol/kg per min. Three groups of patients were identified on the basis of aldosterone response to [des-Asp]-AII. Group I, composed of normotensive control subjects, showed incremental increases in plasma aldosterone concentration from 6+/-1 to 14+/-3 ng/100 ml (P < 0.01) with [des-Asp]-AII infusion. Group II, composed of patients with primary aldosteronism, showed incremental increases in plasma aldosterone concentration from 33+/-8 to 65+/-13 ng/100 ml (P < 0.05) with 12 pmol/kg per min of [des-Asp]-AII. Group III, also composed of patients with primary aldosteronism, showed no increase of plasma aldosterone concentration with [des-Asp]-AII. Groups I and II showed similar percentage increases in plasma aldosterone concentration (P = NS). Group III showed significantly lower aldosterone responses than group I (P < 0.01). Group II included all patients with IHA and two patients with APA. Group III included only patients with APA. The blood pressure responses to [des-Asp]-AII of subjects in group I did not differ significantly from those of groups II or III.Thus, patients with IHA and a subgroup of patients with APA showed responsiveness to [des-Asp]-AII which was limited to adrenal cortical stimulation of aldosterone biosynthesis. This suggests that adrenal responsiveness to angiotensin is a major control mechanism in some forms of primary aldosteronism. The differential adrenal responsiveness to [des-Asp]-AII in patients with APA indicates either that there are two distinct subpopulations of APA, or that alteration in tumor response to angiotensin occurs during the natural progression of the disease history.

Pseudohypoaldosteronism: multiple target organ unresponsiveness to mineralocorticoid hormones

The first report of a 7-month-old male with pseudohypoaldosteronism in which unresponsiveness to mineralocorticoids has been demonstrated in the kidney, colon, and sweat and salivary glands is presented here. This is documented by urinary, salivary, and sweat sodium wasting in the presence of elevated urinary aldosterone excretion, plasma aldosterone concentration, and PRA. There was no mineralocorticoid response in the kidney or salivary or sweat glands to the administration of high doses of 9 alpha-flurocortisol. Furthermore, in this patient, the colonic mucosal cells failed to respond to exogenous aldosterone administration. Repeat evaluation at 25 months of age showed persistence of the sodium wasting and multiple target organ insensitivity to administered mineralocorticoid. Since this patient has defective mineralocorticoid response in the major sodium-conserving organs, the only therapy possible was administration of sodium to compensate for total sodium loss.

Poorly differentiated lymphocytic lymphoma with ectopic parathormone production: visulization of metastatic calcification by bone scan

Metastatic soft tissue calcification is known to occur in hypercalcemia and is usually present in the kidneys, stomach and lungs. 1--3 This case presents two unusual features: 1) ectopic parathormone production in association with poorly differentiated lymphocytic lymphoma; and and 2) uptake of 99mTc-pyrophosphate in the liver in the absence of demonstrable abnormality at autopsy. The more usual sites of metastatic calcification also showed uptake of the radionuclide. We will discuss metastatic soft tissue calcification, ectopic parathyroid hormone production, hypercalcemia in malignancy and bone scan agent localization in soft tissues.

Evidence for a splanchnic sodium input monitor regulating renal sodium excretion in man. Lack of dependence upon aldosterone

Eight normal male subjects were placed on a constant 10 mEq sodium, 60 mEq potassium diet for 5 days. At 8:00 a.m. on the 5th day, the subjects were given a standard dose of 100 mEq of sodium orally or intravenously. Subjects receiving oral sodium also received 200ml of 5% dextrose in water intravenously, and those receiving intravenous sodium also received placebo capsules orally. Water intake and posture were controlled. The subjects then returned to a free diet for 1 month and subsequently were restudied by using the opposite route of sodium administration. The subjects given the oral sodium load excreted greater quantities of sodium in their urine than those repleted intravenously. The differential natriuresis was significant as early as 2 hours after sodium loading. Plasma aldosterone concentration was similar irrespective of the route of sodium administration. Six patients with primary adrenocortical insufficiency and documented hypoaldosteronism were studied with the same protocol after 5 days of 50 mEq sodium, 60 mEq potassium intake. They also had significantly greater natriuresis after oral than intravenous sodium administration. The data suggest the presence of a splanchnic input monitor for sodium which partially regulates renal sodium excretion and is not dependent upon a turn-off mechanism for aldosterone secretion.

The immediate pressor effect of saralasin in man

An immediate pressor response to [Sar1-Ala8]-angiotensin II (saralasin) is described in all of 16 hypertensive subjects. Blood pressure rose within 1-3 min, peaked at 4-6 min, then returned toward baseline. Plasma norepinephrine and dopamine beta-hydroxylase activity were unchanged by saralasin, indicating that the pressor response is not mediated by saralasin-induced catecholamine release. Ten normal renin hypertensives had diastolic pressor responses of 19.4 +/- 3.3 mm Hg. After 5 weeks of diuretic therapy, the diastolic pressor responses to saralasin were decreased to 4.9 +/- 2.4 mm Hg. Six low renin hypertensives had diastolic pressor responses of 26.2 +/- 6.2 mm Hg, but 5 weeks of diuretic therapy did not decrease these pressor responses significantly. In two normal and two low renin hypertensives, the diastolic blood pressure rose to levels greater than 150 mm Hg. The amplitudes of the immediate pressor responses were inversely correlated with the base-line plasma renin activities, r = -0.46. The data support the concept that the agonist activity of saralasin occurs at the angiotensin II vascular receptor level with clinical expression mediated by sodium and/or volume changes.

Activity of (des-Aspartyl1)-angiotensin II and angiotensin II in man. Differences in blood pressure and adrenocortical response during normal and low sodium intake

This study was designed to compare the effect of [des-Aspartyl(1)]-angiotensin II ([des-Asp]-A II) and angiotensin II (A II) on blood pressure and aldosterone production in man under conditions of normal and low sodium (Na) intake. Seven normal male subjects in balance on constant normal Na intake (U(Na) V 160.3+/-5.0 meq/24 h) for 5 days received A II and [des-Asp]-A II infusions on two consecutive days; 1 mo later they were restudied after 5 days of low Na intake (U(Na) V 10.5+/-1.6 meq/24 h). Each dose was infused for 30 min, sequentially. During normal Na intake, [des-Asp]-A II from 2 to 18 pmol/kg per min increased mean blood pressure from 85.2+/-3 to 95.3+/-5 mm Hg and plasma aldosterone concentration from 5.2+/-1.1 to 14.3+/-1.9 ng/100 ml. During low Na intake, the same dose of [des-Asp]-A II increased mean blood pressure from 83.7+/-3 to 86.7+/-3 mm Hg and plasma aldosterone concentration from 34.4+/-6.0 to 51.0+/-8.2 ng/100 ml. In contrast, A II from 2 to 6 pmol/kg per min during normal Na intake increased mean blood pressure from 83.3+/-4 to 102.3+/-4 mm Hg and plasma aldosterone concentration from 7.0+/-2.2 to 26.8+/-2.0 ng/100 ml; during low Na intake, A II increased mean blood pressure from 83.0+/-3 to 96.0+/-4 mm Hg and plasma aldosterone concentration from 42.0+/-9.7 to 102.2+/-15.4 ng/100 ml. A II and [des-Asp]-A II were equally effective in suppressing renin release. Plasma cortisol and Na and K concentration did not change. The effects of two doses (2 and 6 pmol/kg per min) of each peptide on blood pressure and aldosterone production were evaluated. During normal Na intake, [des-Asp]-A II had 11-36% of the pressor activity and 15-30% of the steroidogenic activity of A II. Na deprivation attenuated the pressor response and sensitized the adrenal cortex to both peptides, but the increase in steroidogenesis was greater with [des-Asp]-A II than with A II. The dose-response curves for [des-Asp]-A II with respect to blood pressure and aldosterone production were not parallel, and although no maximum was established for A II, [des-Asp]-A II was less efficacious.In summary, (a) [des-Asp]-A II has biologic activity in man, (b) [des-Asp]-A II is less efficacious than A II in stimulating aldosterone production, (c) Na deprivation sensitizes the adrenal cortex more markedly to [des-Asp]-A II than A II, and (d) dose-response curves for the two peptides differ, suggesting the possibility that they act at different receptor sites in vascular smooth muscle and the adrenal cortex.

Clinical experience with saralasin infusion in hypertensive patients

Renal arteriography gives a reliable anatomic delineation of the renal vasculature. However, the presence of renal arterial disease does not determine the physiologic significance of the lesion. The intravenous infusion of saralasin, a specific angiotensin II antagonist, has been investigated as a method for identifying patients with hypertension dependent upon excessive angiotensin II activity. Correlations between the blood pressure response to saralasin infusion, peripheral and differential renal vein plasma renin levels and renal angiography have been obtained in 35 hypertensive patients. The results suggest that a hypotensive response to saralasin infusion provides an adjunct to renin determinations for recognizing angiotensinogenic renovascular hypertension. However, false negative responses to saralasin occur. The reasons for these negative responses need to be determined before saralasin infusion can be employed as the sole screening test for renovascular hypertension.

The effects of ovine prolactin on water and electrolyte excretion in man are attributable to vasopressin contamination

Prolactin is an important osmoregulatory hormone in several lower vertebrate species. The present study was undertaken to clarify the effects of prolactin, if any, on human renal function. Eight normal adult male subjects on a 150 mEq sodium (Na), 60 mEq potassium (K) diet for 5 days were studied during 12 h of oral water (H2O) loading on 2 consecutive days. On day 1, after a 6 h control period, a 1 ml normal saline placebo was given im; on day 2, 25 mg of ovine prolactin (OP) was substituted. The subjects were supine and received a constant infusion of Na and K. After OP, serum prolactin rose from 6.9+/-0.8 ng/ml to 15.0+/-2.5 ng/ml (P less than .01) at 1 h, 27.6+/-4.0 ng/ml (P less than .002) at 2 h, 33.1+/-4.3 ng/ml (P less than .001) at 3 h and remained elevated for the remaining 3 h of study. The ovine prolactin had 20-25% of the potency of human prolactin in the human prolactin radioimmunoassay system. In response to OP, free H2O clearance (CH2O) promptly decreased from 10.1 +/- .06 ml/min to 6.1 +/- .05 ml/min (P less than 0.1) at 1 h, to a nadir of 5.1+/-.3 ml/min (P less than .001) at 2 h, and returned to control levels by 4 h. CH2O was unchanged after placebo, and urinary Na and K excretion, creatinine and osmolar clearance (COSM), plasma Na, K, osmolality and aldosterone were unchanged after OP or placebo. Control plasma vasopressin was 1.0+/-0.1 micronU/ml and was not changed after prolactin (1.1+/-0.1 micronU/ml at 1 h, 1.1+/-0.1 micronU/ml at 2 h and 1.1+/-0.1 micronU/ml at 3 h). The ovine prolactin contained 2 micronU of immunoassayable vasopressin per microng of powder. Aqueous vasopressin, 50 mU (containing in 25 mg of ovine prolactin), produced a decrease in CH2O not significantly different from prolactin in 6 water loaded subjects. Four different subjects given 100 mg of OP had decreased CH2O from 8.3+/-0.3 to 2.7+/-0.7 ml/min at 1 h (P less than .001) and to 2.8+/-0.7 ml/min at 2 h (P less than .01). Control plasma osmolality was 301+/-4 mOsm/1 and decreased to a maximum of 288+/-5 mOsm/1 4 h after OP (P less than .001). After prolactin administration, plasma vasopressin rose from 0.44+/-0.15 to 0.80+/-0.41 micronU/ml (P =NS) at 1 h. The transient antidiuresis in response to ovine prolactin is due to contamination of the preparation with vasopressin. Prolactin does not acutely influence renal electrolyte excretion and probably does not influence water excretion in man.

Production of sustained hypertension by chronic intrarenal norepinephrine infusion in conscious dogs

The purpose of this study was to determine whether increased sympathetic nervous system activity with proportionally greater stimulation to the kidney could result in sustained hypertension. This was simulated by continuous intrarenal norepinephrine infusion. Effects of chronic infusion of norepinephrine (0.285 microng/kg per min) into the renal artery and inferior vena cava were compared in uniephrectomized conscious dogs. Ten days of intrarenal norepinephrine infusion produced a sustained rise in mean arterial pressure (25 mm Hg), and a 32-mEg positive sodium balance occurred. Inferior vena caval infusion caused a transient rise, lasting 24 hours, in mean arterial pressure which was associated with a 54-mEq natriuresis. With renal artery infusion, peripheral plasma renin activity rose from 1.0 +/- 00.2 to 4.4 +/- 0.8 ng angiotensin I/ml per hour at 1 hour (P less than 0.002) and fell to 1.4 +/- 0.4 at 24 hours (not significant). Inferior vena caval infusion produced a similar result. [Sar1,ala8]angiotensin II (6 MICrong/kg per min) produced no significant change in arterial blood pressure. (alpha-Adrenergic blockade with phentolamine normalized the blood pressure. Renal plasma flow was chronically decreased by about 25% in dogs given intrarenal norepinephrine; no significant change in glomerular filtration rate occurred. The cardiac output decreased from a control of 7.2 +/- 0.6 to 4.8 +/- 0.1 liters/min (P less than 0.01) and total peripheral resistance was increased from a control of 13 +/- 1 to 26 +/- 1 resistance units (RU) (P less than 0.0005) in dogs given intrarenal norepinephrine. The data indicate that chronic intrarenal infusion of norepinephrine in uninephrectomized conscious dogs results in sustained hypertension characterized by decreased renal plasma flow, normal glomerular filtration rate, positive sodium balance, and increased total peripheral resistance due to norepinephrine-dependent vasoconstriction.

The Charlottesville blood pressure survey: the role of the physician in hypertension case finding

The population of a community of 29,608 adults was screened door-to-door for elevated blood pressure. A questionnaire was administered and analyzed to profile the hypertensive person who is most likely to be unaware of his problem. One hundred and one people with documented sustained hypertension were "unaware" of their problem. Of these, 58% had a diastolic blood pressure consistently greater than 100 mm Hg. Sixteen per cent of all hypertensive males were unaware of their problem compared to 5% of hypertensive females. Of those less than 35 years old, 38% of males were unaware compared with 4% of females. White (11%) persons were more apt to be unaware than non-white persons (6%). No person with a positive family history of hypertension was unaware. Ninety-one per cent of all unaware hypertensives had a regular physician. Sixty per cent had consulted a physician within 18 months, and 92% had consulted a physician within 60 months of the survey. The screening process was completed on only 21% of all adults in the target community. These data suggest that the young, white, hypertensive male with no family history of hypertension is most likely to be unaware of his problem. Routine measurement of blood pressure by physicians may be more efficient than door-to-door surveys in contacting the unaware hypertensive person.

Intrarenal renin-angiotensin-sodium interdependent mechanism controlling postclamp renal artery pressure and renin release in the conscious dog with chronic one-kidney Goldblatt hypertension

We studied postclamp renal artery pressure and renin release in eight conscious dogs with one-kidney Goldblatt hypertension. On normal sodium intake, intrarenal blockade of angiotensin II with Sar1-Ala8-angiotension II (P-113, saralasin acetate) markedly decreased postclamp renal artery pressure and increased renin release during the first 5 days after renal artery constriction. We found that 10-14 days after renal artery constriction, the maintenance of postclamp renal artery pressure and negative feedback on renin release became markedly less dependent on angiotensin II, as shown by almost no change in postclamp renal pressure or renin release with intrarenal blockade of angiotensin II. At this stage of our study the dogs were given a sodium diet of less than 5 mEq/day and we found that within 5-10 days intrarenal blockade of angiotensin II once again markedly decreased postclamp renal artery pressure and increased renin release. These observations support the concept of an angiotensin II-sodium interdependent negative feedback mechanism for renin release.