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Biomedical subjects

M Wisgerhof

Publications and source records attributed to M Wisgerhof.

At least 19 recordsLinked to original sources

Cushing's disease: dilemmas of diagnosis and management.

Determining the cause of Cushing's disease and correcting the abnormality presents a continuing challenge to the clinician despite remarkable advances in diagnostic and therapeutic techniques. We present seven cases to illustrate 1) the classic disorder cured by pituitary adenomectomy; 2) persistence of the disease after adenomectomy; 3) Cushing's disease manifesting in the puerperium and remitting with dopamine agonist therapy; 4) a patient whose disease relapsed at least five times during 20 years of treatment by adrenalectomy, pituitary radiation, mitotane, and pituitary adenomectomy; 5) the Nelson syndrome; 6) the ectopic adrenocorticotropic hormone (ACTH) syndrome in a patient with dexamethasone suppressible urinary cortisol who had a pituitary adenoma which stained positively for ACTH but who was not cured by total hypophysectomy; and 7) a patient whose ACTH-secreting tumor proved fatal despite repeated surgical, radiologic and pharmacologic measures.

Adrenocorticotropic Hormone↗

Conn's syndrome with rhabdomyolysis mimicking deep vein thrombophlebitis.

We have reported a case of Conn's syndrome, with pain, tenderness, and swelling of the calf mimicking deep vein thrombophlebitis. The symptoms were associated with sever hypokalemia and rhabdomyolysis, and these findings subsequently explained by primary aldosteronism, which was cured by adrenalectomy.

Adenoma↗

Effect of bromocriptine treatment on the aldosterone response to angiotensin II and adrenocorticotropin in idiopathic hyperaldosteronism.

Bromocriptine can prevent an increase in plasma aldosterone during the infusion of angiotensin II in normal subjects and during upright posture in some patients with idiopathic hyperaldosteronism. To determine if bromocriptine prevents the increase in plasma aldosterone concentration during angiotensin II infusion in idiopathic hyperaldosteronism, we infused angiotensin II in five patients with idiopathic hyperaldosteronism, before and after treatment with bromocriptine (2.5 mg, three times daily for 5 days), and measured the resulting plasma aldosterone and angiotensin II concentrations. We also determined the adrenal response to ACTH infusion before and after bromocriptine treatment in four of these patients. Bromocriptine treatment did not significantly change the plasma concentrations of aldosterone before or during the infusions of angiotensin II and ACTH. It did significantly decrease mean blood pressure and increase the plasma corticosteroid concentrations in the preinfusion periods, but it did not alter the response of blood pressure to angiotensin II or of plasma corticosteroid concentrations to the ACTH infusions.

Adrenal Cortex Hormones↗

In vitro responses of aldosterone-producing adenomas to angiotensin II and ACTH after treatment with spironolactone before adrenalectomy.

Aldosterone-producing adenomas in patients who have not been given spironolactone are more responsive to ACTH than to angiotensin II. In vitro, adenomas respond to ACTH, but their response to angiotensin II has not been clearly defined. Treatment with spironolactone has been given before the removal of some of the adenomas studied in vitro, and it can blunt increases in plasma aldosterone concentrations that occur in response to increases in renin activity. To assess the effect of preoperative spironolactone therapy on the responsiveness of aldosterone-producing adenomas in vitro, tissue from five patients with adenomas was incubated for 4 hours with and without angiotensin II and ACTH, 10(-7) to 10(-5) mol/L. The responsiveness of the adenomas was then related to the duration of preoperative spironolactone therapy. The serum potassium concentration was normal in the patients before the operations. Adenoma tissue from a patient given spironolactone for 4 days was responsive to angiotensin II and to ACTH. Treatment of longer duration with spironolactone appeared to be associated with a pattern of decreasing responsiveness to ACTH and an absence of response to angiotensin II in vitro. Aldosterone production by nonadenomatous adrenal tissue did not respond to angiotensin II or to ACTH. Our results suggest that preoperative spironolactone therapy might decrease the responsiveness of aldosterone-producing adenomas to angiotensin II and ACTH in vitro. Therefore, studies of aldosterone-producing adenomas in vitro should consider the possible effects of preoperative treatment with spironolactone on the responsiveness of the adenomas to angiotensin II and ACTH.

Adenoma↗

Aging and aldosterone.

We measured urinary and plasma aldosterone in normal subjects, aged 20 to 59 years, during a period of unrestricted sodium intake and after sodium depletion, using furosemide or a 20 meq sodium diet. Before and after sodium depletion, the mean and the upper limit of the range of urinary aldosterone excretion were considerably lower in subjects over 50 years compared with subjects under 30 years. Aging had no effect on plasma aldosterone concentration when the subjects were on an unrestricted sodium diet and blood was sampled while they were recumbent. In contrast, when the subjects were upright, both before and after sodium depletion, the mean and the upper limit of the range of plasma aldosterone concentration were lower in the subjects over 50 years compared with those under 30 years. The metabolic clearance of aldosterone was the same in the younger and the older subjects. Of eight patients over 40 years of age with aldosterone-producing adenoma, four had normal aldosterone excretion rates when the normal range was not age adjusted, but with age adjustment, all of the patients had clearly elevated excretion rates. Similarly, six of seven patients over 40 years of age had normal upright plasma aldosterone concentrations if the normal range of plasma aldosterone concentration was not age adjusted. We conclude that aldosterone secretion declines with advancing age. The effect of age on aldosterone secretion is an important consideration when evaluating older hypertensive patients for primary aldosteronism.

Adenoma↗

Failure of angiotensin II to stimulate increases in concentrations of adrenal androgens, 17-hydroxyprogesterone, or adrenocorticotropin in congenital 21-hydroxylase deficiency.

To determine if angiotensin II stimulates an increase in the plasma concentration of androstenedione, dehydroepiandrosterone, 17-hydroxyprogesterone, or ACTH in a patient with congenital 21-hydroxylase deficiency, we measured these plasma concentrations before and after the plasma angiotensin II concentration was increased by upright posture and angiotensin II infusion in a surgically castrate XX adult patient with this disorder. The patient was studied before treatment, after treatment with 1 mg dexamethasone daily for 3 weeks, and after treatment with both dexamethasone and 0.2 mg fludrocortisone daily for 3 weeks. The plasma concentrations of androstenedione, dehydroepiandrosterone, and 17-hydroxyprogesterone did not change consistently during increases in the angiotensin II concentration. The ACTH concentration did not increase in response to raised angiotensin II concentrations before or after steroid treatment. During the infusion of angiotensin II, blood pressure increased and renin activity decreased appropriate in degree to the preinfusion concentration of angiotensin II. The results from the study of this patient do not support the hypotheses that in congenital 21-hydroxylase deficiency, angiotensin II directly stimulates adrenal androgen secretion or that angiotensin II stimulates ACTH secretion.

17-alpha-Hydroxyprogesterone↗

The plasma aldosterone response to angiotensin II infusion in aldosterone-producing adenoma and idiopathic hyperaldosteronism.

To determine if the adrenal sensitivity to angiotensin II in patients with an aldosterone-producing adenoma differs from that in patients with idiopathic hyperaldosteronism, we infused graded doses of angiotensin II into 17 patients with primary aldosteronism and measured their plasma aldosterone concentrations after each dose. At a rate of 0.5 ng angiotensin II/kg.min, the mean increase in the plasma aldosterone concentration in the 8 patients from whom an aldosterone-producing adenoma was subsequently removed was 4 +/ 2.4 ng/dl (mean +/- SE), which was significantly less (P less than 0.01) than the mean increase (23 +/- 4.8 ng/dl) in the 9 patients with idiopathic hyperaldosteronism. The threshold dose of angiotensin II in the patients with aldosterone-producing adenoma was 1.0 +/- 0.24 ng/kg.min, significantly greater (P less than 0.05) than the threshold dose (0.3 +/- 0.07 ng/kg.min) in the patients with idiopathic hyperaldosteronism. We conclude that the sensitivity of aldosterone-producing adenomas to angiotensin II is significantly less than that of the hypersecreting adrenal tissue in patients with idiopathic hyperaldosteronism. This difference in adrenal sensitivity might in part explain the difference in the response of plasma aldosterone concentrations to upright posture in these two subsets of aldosteronism with low renin activity.

Adenoma↗

Effect of metoclopramide on the secretion and metabolism of aldosterone in man.

We performed this study to determine whether metoclopramide increases the concentration of plasma aldosterone in normal man by increasing the secretion rate of aldosterone or by decreasing aldosterone metabolic clearance. On the first day that metoclopramide was administered orally to seven normal subjects, the secretion rate of aldosterone increased significantly (P less than 0.05) from the rate during the preceding placebo period. By the fourth day of treatment, the secretion rate had returned to control values and remained there during an ensuing placebo period. The excretion rate of aldosterone followed a similar pattern. The increase in aldosterone secretion was accompanied by a transient but significant decrease in urinary sodium excretion. Metoclopramide administered iv had no effect on the metabolic clearance of aldosterone. Metoclopramide stimulated aldosterone-producing adenomas and nodular hyperplastic adrenal tissue resected from patients with primary aldosteronism to produce aldosterone in vitro. We conclude that metoclopramide increases the concentration of aldosterone in plasma by stimulating the secretion of aldosterone rather than by decreasing aldosterone metabolic clearance, and that metoclopramide probably stimulates aldosterone secretion by acting directly on adrenal tissue.

Adult↗

The metabolic clearance of aldosterone decreases similarly during infusion of angiotensin II in patients with essential hypertension and in normal subjects.

To determine if the abnormally large increases in levels of plasma aldosterone which occur during infusion of angiotensin II in some patients with essential hypertension are due to abnormal decreases in the metabolic clearance of aldosterone, we measured clearances of aldosterone before and during infusion of angiotensin II in 12 patients with essential hypertension and in 10 normal subjects. The metabolic clearance of aldosterone in the patients and that in the normal subjects were the same before angiotensin II was infused and the clearances decreased similarly during infusion of angiotensin II. In agreement with our previous observations, the plasma aldosterone responses to angiotensin II were greater than normal in most of the patients with low renin essential hypertension. Thus, the brisk increases in levels of plasma aldosterone during infusion of angiotensin II in patients with essential hypertension reflect abnormally large increases in the secretion of aldosterone. These results add further support to the idea that adrenal sensitivity to angiotensin II is increased in some patients with essential hypertension.

Adult↗

Increased adrenal sensitivity to angiotensin II in low-renin essential hypertension.

Studies were undertaken to determine if the dissociation of aldosterone and plasma renin activity in low-renin essential hypertension is due to altered adrenal responsiveness to angiotensin II. The responsiveness of the adrenal glands to angiotensin II was determined by infusing graded doses of angiotensin II into normal subjects and into patients with essential hypertension and measuring changes in levels of plasma aldosterone in response to the infusion. To minimize the influence of endogenous angiotensin II and ACTH, supplemental sodium and dexamethasone were given before the infusions. Levels of plasma aldosterone and plasma renin activity were determined in normal subjects and in the same patients after the combined stimuli of furosemide and upright posture, a maneuver used to increase the level of endogenous angiotensin II. To determine if the changes in levels of plasma aldosterone during infusion of angiotensin II were due to alteration of the metabolic clearance of aldosterone, the metabolic clearance of aldosterone was measured before and during the infusion of angiotensin II. After sodium loading, dexamethasone treatment, and supine posture, levels of plasma aldosterone of normal subjects and patients with essential hypertension were suppressed equally. In response to the infusion of angiotensin II, the levels of plasma aldosterone of patients with low-renin essential hypertension were significantly higher than those of normal subjects or of patients with normal-renin essential hypertension. After furosemide and upright posture, levels of plasma aldosterone of patients with low-renin essential hypertension were significantly higher than those of patients with normal-renin essential hypertension, despite a blunted response in plasma renin activity of the patients with low-renin essential hypertension. Decreases in metabolic clearance of aldosterone during infusion of angiotensin II were similar in patients with normal-renin essential hypertension and in patients with low-renin essential hypertension and accounted for only a small fraction of the marked increase in levels of plasma aldosterone of patients with low-renin essential hypertension. It is concluded that patients with low-renin essential hypertension have increased adrenal sensitivity to angiotensin II. This increased sensitivity may explain the dissociation of aldosterone and plasma renin activity in low-renin essential hypertension.

Adrenal Glands↗

Increased adrenal sensitivity to angiotensin II in idiopathic hyperaldosteronism.

Plasma aldosterone increases briskly during upright posture in patients with idiopathic hyperaldosteronism, despite only small increases in PRA and presumably small increases in angiotensin II. To examine the postulate that small increments in angiotensin II mediate these brisk increases in aldosterone, we infused graded doses of angiotensin II into normal subjects and patients with idiopathic hyperaldosteronism and compared the changes in levels of plasma aldosterone in the two groups. Supplemental sodium and dexamethasone were given before the infusion to minimize the influence of endogenous angiotensin II and ACTH. In response to the infusion of angiotensin II, increases in the levels of plasma aldosterone of patients with idiopathic hyperaldosteronism were significantly greater than those of normal subjects. In addition, levels of plasma aldosterone increased at a lower rate of infusion of angiotensin II in patients than in normal subjects. It is concluded that patients with idiopathic hyperaldosteronism have increased adrenal sensitivity to angiotensin II. This increased sensitivity may explain the brisk increases in aldosterone that occur during upright posture in these patients.

Adrenal Glands↗