D. Haack

Vasopressin-mediated blood pressure response to intraventricular injection of angiotensin II in the rat

Abstract1.The role of stimulation of argininevasopressin (AVP) release in the blood pressure (BP) response to intracerebroventricular (ivt) injection of angiotensin II (AII) was investigated.2.Ivt injection of AII to normal Long-Evans (LE) rats, which were conscious and unrestrained, induced a dose-related increase of BP in close correlation with the rise of plasma AVP concentrations (r=0.93;y=34.0 log X-14.4). This regression line crossed the X-axis at plasma AVP concentrations found under control conditions.3.In comparison with the correlation obtained after intravenous injection of AVP (r=0.99;y=35.6 log X-46.9), the correlation between BP increase and plasma AVP after ivt AII exhibited a parallel shift to the left by a factor of 7.5.4.When 0.5 ml of a specific AVP antiserum was injected intravenously, the BP response to subsequent ivt injection of AII was completely blocked in 2 of 7 rats tested and reduced by 50% or more in the other 5 rats.5.In Brattleboro rats homozygous for hereditary hypothalamic diabetes insipidus (DI), in which plasma AVP remained undetectable after ivt AII, BP response was reduced by 50–80% in comparison with the response in LE rats. Drinking response, however, was not altered. During spontaneous drinking, DI rats showed a BP increase of similar magnitude as that after the highest dose of ivt AII.6.We conclude that a close relationship exists in normal LE rats between the rise of BP and of plasma AVP after ivt AII; this correlation represents a cause-effect relationship, since after the intravenous injection of AVP antiserum the BP response to ivt AII is markedly or completely blocked; and sensitization to the vasopressor effect of AVP occurs after ivt AII. The BP increase observed in unrestrained DI rats after ivt AII as well as during spontaneous drinking might be related to a general arousal reaction which would be insignificant in normal LE rats.

Association of testosterone and dihydrotestosterone with externalizing behavior in adolescent boys and girls

BACKGROUND While an association between androgens and different types of aggression has been well documented in male offenders, the influence of androgens on externalizing behavior in adolescents at risk for antisocial behavior has not been investigated so far. METHODS Plasma levels of the main androgen metabolites testosterone (T) and 5alpha-dihydrotestosterone (DHT) were measured in N = 87 fourteen-year-old (36 boys, 51 girls) from a prospective longitudinal study of children at risk. Externalizing behavior at age 8, 11 and 14 was assessed using the Achenbach Child Behavior Checklist (CBCL) and Teacher Report Form (TRF). RESULTS Significant higher androgen levels (T, DHT) were found in male, but not in female adolescents with elevated scores of externalizing behavior. Moreover, boys with persistent externalizing behavior exhibited the highest levels of plasma androgens. CONCLUSIONS There is a link between T, DHT and externalizing behavior in male adolescents at risk for psychopathology. Due to the findings of highest androgen levels in boys with persistent externalizing behavior, a role of androgens in the development of disruptive or later antisocial disorders can be hypothesized.

Development of plasma 21-deoxycortisol radioimmunoassay and application to the diagnosis of patients with 21-hydroxylase deficiency

Specific 21-deoxycortisol (21-DF) antiserum was raised in New Zealand white rabbits using a 21-DF-3,20-oxime-bovine serum albumin complex. Plasma radioimmunoassay of 21-DF was developed and used together with a radioimmunoassay of 17-hydroxyprogesterone (17-OH-P) for diagnosis of patients with 21-hydroxylase deficiency of congenital and postpubertal forms. The assays were performed in plasma extracts after isolation by paper chromatography. The response of plasma 21-DF and 17-OH-P to i.v. ACTH (25 IU) was studied in 15 adult controls and compared to 8 women with the late onset form of 21-hydroxylase deficiency and 23 women with idiopathic hirsutism. Normal 21-DF values for women were 6.9 +/- 3.6 ng/dl and for men 9.71 +/- 2.73 ng/dl. Newborn children (age: 3-10 days) had a value of 8.3 +/- 4.8 ng/dl. These values are definitely lower than the lowest value ever published. This is possibly due to the specificity of the antibody. During the menstrual cycle the 21-DF values did not change. The baseline and post-stimulated concentrations of hormone were similar in controls and women with hirsutism but were significantly higher in women with the late onset form of 21-hydroxylase deficiency. In the congenital form of 21-hydroxylase deficiency the 21-DF values (baseline) were high. In general, the 21-DF and 17-OH-P values have shown parallel changes. However, one case of 21-hydroxylase deficiency with elevated 21-DF but normal 17-OH-P was observed. The use of 21-DF for the diagnosis of 21-hydroxylase deficiency is suggested.

Aldosterone diagnosis in hypertension: comparative evaluation of radioimmunoassays for urinary aldosterone and 18-OH-corticosterone.

ZusammenfassungAldosteron-18-Glucuronid Bestimmungen wurden von Urinproben (n=1119) vor und nach Chromotagraphie mit Hilfe von Antikörpern durchgeführt, die gegen drei verschiedene Typen von Aldosteron Antigenen erzeugt wurden. Die Werte vor und nach Chromatographie zeigten eine hochsignifikante Korrelation. Dennoch lagen die Bestimmungen, die ohne einen Isolierungsschritt vorgenommen wurden, im allgemeinen höher und in Einzelfällen gab es Dissoziationen der Werte. Mit einem Aldosteron-3-oxim-Antiserum wurden die zuverlässigsten Bestimmungen ohne Chromatographie erzielt. Auch mit diesem Antiserum wurden jedoch überhöhte Werte in 4,33% der Tests (n=854) bestimmt, die als klinisch irreführend bezeichnet werden können. Die Technik ohne Chromatographie ist deswegen nur für Screening-Zwecke akzeptabel.Aldosteron-18-Glucuronid, freies Aldosteron, freies 18-Hydroxycorticosteron, freies 18-Hydroxydeoxycorticosteron und Tetrahydroaldosteron wurden radioimmunologisch aus Urinproben von Normalpatienten, von Patienten mit essentieller Hypertonie und mit primärem Hyperaldosteronismus bestimmt. Die Resultate wurden untereinander verglichen. Die verschiedenen Größen korrelierten signifikant miteinander, doch die Korrelationskoeffizienten waren sehr unterschiedlich. Die besten Korrelationen wurden errechnet, wenn freie Urinaldosteron Werte mit den anderen Größen verglichen wurden. Die Bestimmung von Aldosteron-18-Glucuronid ist zur Zeit die am meisten durchgeführte Bestimmung. Bei einer Gruppe von Patienten mit essentieller Hypertonie und auch bei Patienten mit primärem Hyperaldosteronismus waren die Aldosteron-18-Glucuronid Werte innerhalb des Normbereiches, während die Exkretion des freien Urin-Aldosterons und des Tetrahydroaldosterons erhöht war. Wir schließen daraus, daß die Bestimmung des Aldosteron-18-Glucuronids für die Diagnose einer Aldosteron Hyperproduktion nicht immer ausreicht.Es wurde zusätzlich ein Assay für freies 18-Hydroxycorticosteron im Urin entwickelt, um die Aldosteron Diagnostik zu stützen. Der Normalbereich war 1,5–6,5 µg/24 h. Der Durchschnitt (± SD) lag bei 4,0±1,44 µg/24 h. Diese Werte korrelieren besonders gut mit den Bestimmungen von freiem Aldosteron.SummaryAldosterone-18-glucuronide, free aldosterone, free 18-OH-deoxycorticosterone, and tetrahydroaldosterone radioimmunoassays were performed in urine samples from normal subjects, as well as from patients with essential hypertension and primary hyperaldosteronism. The aldosterone-18-glucuronide measurements were made on 1119 urine samples, with and without chromatographic separation, with antisera raised against 3 different types of aldosterone antigens. Good correlations were found between the values obtained with the different methods. However, the values measured without chromatography were usually higher and individual discrepancies between results obtained with and without chromatography were observed. The antiserum raised against an aldosterone-3-oxime antigen produced the most reliable results without prior chromatography, but the values were still higher than after chromatography in 4.33% of 854 cases. These values may be clinically misleading, and we therefore recommend the aldosterone-18-glucuronide estimation without chromatography as a screening method only.When the results of the aldosterone-18-glucuronide, free aldosterone, free 18-OH-deoxycorticosterone, and tetrahydroaldosterone assays were compared, free aldosterone was found to correlate the best with the results of all other assays. There were also correlations among the other assays. The aldosterone-18-glucuronide estimation is currently the most frequently used assay. This study revealed, however, that in patients with essential hypertension and primary aldosteronism, normal aldosterone-18-glucuronide levels can be accompanied by high free aldosterone and tetrahydroaldosterone levels. We conclude, therefore, that the aldosterone-18-glucuronide assay may not be sufficient to select all patients with hyperaldosteronism.Additionally, a radioimmunoassay of urinary free 18-OH-corticosterone was developed and used as an aid in the aldosterone diagnosis. The excretion levels were 1.5–6.5, with a mean value (± SD) of 4.0±1.44 µg/24 h. These values also correlated with the different aldosterone measurements, and correlated best with the free aldosterone values.

Disturbed glucocorticoid receptor autoregulation and corticotropin response to dexamethasone in depressives pretreated with metyrapone

We studied glucocorticoid receptor autoregulation and corticotropin response to dexamethasone in depressed patients and controls, attempting to control for the confounding effect of endogenous glucocorticoids. After depletion of endogenous cortisol, depressed patients showed an attenuated suppressibility of corticotropin by dexamethasone in the face of unchanged dexamethasone plasma levels. Beta-endorphin levels were strongly correlated with adrenocorticotropic hormone (ACTH) concentrations. Although metyrapone administration resulted in a marked rise of glucocorticoid receptor sites per cell in controls, this effect was not present in depressives. These data support the hypothesis of a decreased glucocorticoid receptor plasticity and a partial steroid resistance in depression.

Urinary tetrahydroaldosterone as a screening method for primary aldosteronism: a comparative study

BACKGROUND The major aldosterone metabolite 3 alpha,5 beta tetrahydroaldosterone reflects up to 45% of the aldosterone secretion. Its 24-h urinary excretion is likely to provide an accurate index of the daily aldosterone production and to be an indicator for primary aldosteronism (PA). METHODS In a prospective study, the validity of tetrahydroaldosterone as a screening test for PA was evaluated in comparison to serum potassium, plasma aldosterone, plasma renin activity, plasma aldosterone/renin activity ratio (PARR), as well as 24-h urinary aldosterone-18-glucuronide and free aldosterone. A total of 111 normotensive individuals, 412 PA patients and 1453 essential hypertensive patients, were studied. The effect of blood sampling technique on potassium level was also investigated. RESULTS Tetrahydroaldosterone differentiated PA from essential hypertension with a sensitivity of 96% and a specificity of 95%. The sensitivity was 89% for plasma aldosterone, 87% for free aldosterone, 85% for PARR, 71% for aldosterone-18-glucuronide and 51% for renin activity. Specificities varied between 91% and 85%. The combined use of the parameters plasma aldosterone > or =9.0 ng/dL and PARR > or =25 resulted in a sensitivity of 82% and specificity of 95%. Forearm exercise proved to be a source of erroneous elevations of potassium sufficient to obscure the suspicion of PA. CONCLUSION The data suggest that tetrahydroaldosterone is the most reliable screening test for PA. Tetrahydroaldosterone determination in combination with aldosterone-18-glucuronide and free aldosterone increases diagnostic specificity for PA. Potassium, renin, plasma aldosterone, and basal PARR are inadequate screening procedures because they are subject to high rates of false-positive and false-negative results.

Aldosterone metabolites and possible aldosterone precursors in hypertension

The value of the urine tests: free aldosterone, aldosterone-18-glucuronide, tetrahydroaldosterone 18-hydroxycorticosterone and 18-hydroxydeoxycorticosterone in distinguishing primary aldosteronism from essential hypertension was studied in patients with typical and atypical primary aldosteronism and in patients with essential hypertension. The discriminating function of the tetrahydroaldosterone determination was the best, followed by 18-hydroxycorticosterone, free aldosterone and aldosterone-18-glucuronide. The measurement of 18-hydroxydeoxycorticosterone was without distinguishing value. Three cases with hypertension, adrenal adenoma, elevated 18-hydroxycorticosterone but normal aldosterone values were observed. In longitudinal studies the excretions of aldosterone, aldosterone metabolites and possible precursors periodically varied independently of each other. Determinations of urine aldosterone, aldosterone metabolites, 18-hydroxycorticosterone and 18-hydroxydeoxycorticosterone were not applicable for differential diagnosis of the adenoma and hyperplasia forms of primary aldosteronism.

The effect of chronic ACTH treatment on blood pressure and urinary excretion of steroids in the rat

ZusammenfassungACTH in Depotform wurde Ratten subcutan 14 Tage lang injiziert. Gemessen wurden die Veränderungen des Körpergewichtes im Verhältnis zur Wasserbilanz, des Blutdruckes und der Steroidausscheidung im Urin. Es fand sich eine Gewichtsabnahme, vorwiegend durch Wasserverlust bedingt und ein schneller Blutdruckanstieg bis zum 10. Tag. Während der Behandlung waren die Urinausscheidung von Corticosteron und 18-OH-Desoxycorticosteron um mehr als das zehnfache erhöht; die Aldosteronausscheidung war nur während der ersten zwei Tage erhöht. Nach Absetzen der ACTH-Therapie normalisierten sich Wasserbilanz und Steroidausscheidung weitgehend, während der Blutdruck nach 10 Tagen noch leicht erhöht war. Die Wirkungen von ACTH auf Wasserbilanz und Blutdruck gleichen im wesentlichen denen von Corticosteron, dessen Exkretion auch am stärksten stimuliert wurde. Die ACTH-Hypertonie der Ratte scheint durch einheitlich schnelle und anhaltende Blutdruckerhöhung ein geeignetes Modell zum Studium der Hochdruckentstehung zu sein.SummaryThe effects of subcutaneous injections of synthetic ACTH during 14 subsequent days has been studied in the rat. ACTH caused a loss in body weight which was related to a negative water balance. Blood pressure rose rapidly and reached values higher than 180 mm Hg in all rats after 10 days of ACTH administration. During this period, urinary excretion of corticosterone and 18-hydroxy-deoxycorticosterone (18-OH-DOC) was increased more than ten times, while aldosterone excretion was increased only during the first two days. After withdrawal of ACTH, excretion of steroids normalized, or in some cases was even suppressed and water balance and body weight gain returned to normal values. However, blood pressure remained slightly higher than in controls after ten days. The effects of ACTH on water balance and blood pressure resemble those of corticosterone in the rat. The rapidly induced and sustained changes in blood pressure by ACTH administration suggest that this may be an useful model of experimental hypertension.

IS VASOPRESSIN INVOLVED IN THE PATHOGENESIS OF MALIGNANT DESOXYCORTICOSTERONE HYPERTENSION IN RATS

Rats with unilateral nephrectomy were offered 1% sodium chloride as drinking fluid and were injected with desoxycorticosterone trimethylacetate (D.O.C.-T.M.A.) at weekly intervals. During the fourth to seventh week after the start of the experiment, malignant hypertension developed in most of the animals: body weight fell, reflecting volume depletion; serum osmolality and serum sodium and urea concentrations increased; in the kidneys malignant nephrosclerosis occurred. In such animals, plasma concentrations of arginine-vasopressin were increased ten-fold in comparison with control animals; intravenous injection of a specific vasopressin antibody resulted in a transient fall of blood-pressure (B.P.) to normal or subnormal levels, while the injection of an angiotensin-I or angiotensin-II antibody did not affect B.P. In control animals none of the antibodies had an effect on B.P. It is concluded that in the pathogenesis of malignant D.O.C. hypertension vasopressin plays a role similar to that of renin-angiotensin in malignant renal hypertension.

Elevated ‘free’ 18-hydroxy-corticosterone excretion as a possible indicator for early diagnosis of primary aldosteronism

Abstract Urinary “free” (unconjugated) 18-hydroxy-corticosterone (18-OH-B), together with aldosterone-18-glu-curonide, “free” aldosterone and tetrahydroaldosterone were determined in 20 patients with primary aldosteronism. In 19 out of 20 cases (both in adenoma and hyperplasia) the 18-OH-B excretion was at least temporarily increased. On the basis the measurement of the 18-OH-B excretion was applied-in addition to determinations of aldosterone and aldosterone-metabolites-to search for cases of primary aldosteronism. Increased 18-OH-B excretion was found in 20 of 165 pre-selected patients with essential hypertension. In 11 of them, at least one of the urinary aldosterone values was concomitantly elevated. In 9 patients the aldosterone values were found to be within normal ranges. Follow-up studies have shown elevated aldosterone values in some members of the latter group, and in 3 patients first believed to have essential hypertension adrenal adenomas were established. In 2 patients the adenoma was removed.