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Biomedical subjects

B Ambrosi

Publications and source records attributed to B Ambrosi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Usefulness of the desmopressin test in the postoperative evaluation of patients with Cushing's disease.

OBJECTIVE: To evaluate the plasma ACTH and serum cortisol responses to desmopressin in patients with Cushing's disease either before or after pituitary adenomectomy during long-term follow-up, and to compare the results with those obtained after corticotrophin-releasing hormone (CRH) testing. DESIGN: Plasma ACTH and serum cortisol concentrations were evaluated after the administration of desmopressin (10 microg i.v.) or CRH (1 microg/kg i. v.) in 34 patients with Cushing's disease. Twenty-four patients with active Cushing's disease were evaluated both before and after transsphenoidal pituitary surgery (TSS); these patients were followed up for 1-36 months. Ten patients were studied only after a long-term period (1-19 years, median 4 years) after TSS (six patients), TSS plus external pituitary irradiation (three patients) and TSS plus radiosurgery (one patient). RESULTS: In 24 patients with active Cushing's disease a significant ACTH/cortisol response (P<0.001) was induced by either desmopressin (ACTH from a baseline of 15.3+/-2.7 pmol/l to a peak of 40.9+/-7.3 pmol/l; cortisol from 673+/-59 nmol/l to 1171+/-90 nmol/l) or CRH (ACTH from a basal of 14. 2+/-2.5 pmol/l to a peak of 47.2+/-7.7 pmol/l; cortisol from 672+/-50 nmol/l to 1192+/- 80 nmol/l). In all patients a positive cortisol response to desmopressin was found. After pituitary adenomectomy the 14 'cured' patients were followed up for 1-36 months; desmopressin administration never induced ACTH or cortisol responsiveness in any patient. In contrast, a progressive recovery of ACTH and cortisol responses after CRH was observed at different intervals of time in all patients but one. Five patients, in whom the cortisol concentration only normalized after surgery, showed a persistent responsiveness to desmopressin, and two of them relapsed 12 and 24 months later. In five patients who were not cured, the hormonal responsiveness to either CRH or desmopressin was similar before and after operation. Of 10 patients studied only after long-term follow-up, six were cured and a normal response to CRH was present, whereas no changes in ACTH/cortisol concentrations were induced by desmopressin. The other four unsuccessfully operated patients underwent pituitary irradiation and showed different and equivocal hormonal responses to desmopressin and to CRH. CONCLUSIONS: During the postoperative follow-up of patients with Cushing's disease, the maintenance or the disappearance of the hormonal response may be related to the persistence or the complete removal of adenomatous corticotrophs, respectively. It is suggested that desmopressin test should be performed in the preoperative evaluation and follow-up of patients with ACTH-dependent Cushing's syndrome.

Adolescent↗
PubMed1998

Evaluation of markers of bone and collagen turnover in patients with active and preclinical Cushing's syndrome and in patients with adrenal incidentaloma.

Although steroid-induced negative effects on bone and collagen have been well described in corticosteroid-treated patients, few studies have extensively evaluated bone and collagen turnover in patients with endogenous Cushing's syndrome. In this work serum bone-Gla protein (BGP), C-terminal cross-linked telopeptide of type I collagen (ICTP) and N-terminal propeptide of type III procollagen (PIIINP) levels were determined in patients with active (n = 12) and preclinical (n = 6) Cushing's syndrome, adrenal incidentalomas (n = 35) and in healthy controls (n = 28). In patients with overt Cushing's syndrome, serum BGP (0.9+/-0.2 ng/ml), ICTP (2.7+/-0.2 ng/ml) and PIIINP (1.9+/-0.2 ng/ml) levels were significantly lower (P < 0.0001) than in controls (5.5+/-0.2, 3.9+/-0.2 and 3.2+/-0.2 ng/ml respectively). In preclinical Cushing's syndrome, serum BGP (2.5+/-0.8 ng/ml), ICTP (2.2+/-0.1 ng/ml) and PIIINP (2.2+/-0.2 ng/ml) levels were significantly lower than in normal subjects (P < 0.0001, P < 0.0001 and P < 0.02 respectively), being similar to those recorded in overt Cushing's syndrome. In patients with adrenal incidentaloma, serum BGP (4.2+/-0.5 ng/ml) and ICTP (2.9+/-0.2 ng/ml) levels were significantly lower than those found in controls (P < 0.05 and P < 0.001 respectively), while serum PIIINP levels (3.6+/-0.2 ng/ml) did not differ from those of normals. In particular, 9/35 patients with adrenal incidentaloma had markedly depressed BGP levels (<2.0 ng/ml; mean 0.8+/-0.1 ng/ml): all patients of this subgroup showed an exaggerated 17-hydroxyprogesterone increase after ACTH administration. In the same patients, serum ICTP (3.0+/-0.4 ng/ml) and PIIINP (3.6+/-0.2 ng/ml) levels did not differ from those found in the incidentaloma group. In conclusion, our study indicates that bone and collagen turnover are markedly affected in patients with overt and preclinical Cushing's syndrome. Although patients with adrenal incidentaloma do not show any signs or symptoms of overt hypercortisolism, the presence of reduced BGP and ICTP levels might be considered a further index of an 'abnormal' pattern of steroid secretion in some of them. As a consequence, the presence of early alterations in markers of bone turnover might be useful for selecting those patients who need more accurate follow-up of the adrenal mass.

Adrenal Gland Neoplasms↗
PubMed1998

The one microgram adrenocorticotropin test in the assessment of hypothalamic-pituitary-adrenal function.

The possibility of assessing hypothalamic-pituitary-adrenal (HPA) function by the standard ACTH test (250 microg) has been widely discussed in the past years and compared with the role of the insulin tolerance test (ITT). Recently, it was shown that low doses of ACTH, such as 1 microg i.v., induce a maximal adrenal response and, by reducing the discrepancies compared with the ITT also allow one to detect mild forms of secondary hypoadrenalism. In the present study the 1 microg ACTH test was performed in patients with hypothalamic-pituitary disease in order to assess adrenal function, and the results have been compared with those obtained after the insulin test. Fifty-seven patients (31 men and 26 women, aged 19-73 years) with hypothalamic-pituitary diseases were studied: 51 patients were affected with pituitary tumor and 6 patients had hypothalamic disorders. All these patients and 18 healthy volunteers (7 men and 11 women, aged 19-46 years) received 1 microg i.v. ACTH injection. In addition, the ITT (0.1-0.15 U/kg body weight) was performed in all patients. In normal subjects mean cortisol levels significantly (P<0.001) increased from a baseline of 393+/-43 nmol/l to a peak of 770+/-41 nmol/l after 1 microg ACTH. In 44 patients with hypothalamic-pituitary disease 1 microg ACTH caused a cortisol rise similar to that of normal subjects (from 332+/-17 to 769+/-24 nmol/l; P<0.001), while an impaired response (from 124+/-23 to 312+/-46 nmol/l) was observed in 13 cases (23%), 7 of them with low morning cortisol levels (10-127 nmol/l) and 6 with basal values at the lower limit of normality. The cortisol response to ITT was compared with that obtained after the 1 microg ACTH test: 10 patients failed both challenges, 4 patients who passed the ACTH test failed the ITT, while 3 patients who failed the ACTH test passed the ITT. The 23 out of 57 patients (40%) who showed a cortisol peak greater than 750 nmol/l after 1 microg ACTH had a normal response to ITT. A positive correlation between cortisol peaks after ACTH and after insulin was also found (r = 0.68, P<0.001). Assuming a 100% accuracy of ITT, the low dose ACTH test yielded a 71% sensitivity and a 93% specificity. In conclusion, the low-dose ACTH test is a useful, safe and inexpensive tool for the initial assessment of HPA function in patients with hypothalamic-pituitary disease. In fact, the ITT is unnecessary when cortisol peaks are greater than 750 nmol/l after 1 microg ACTH and also when very low cortisol basal levels indicate an overt hypoadrenalism. Within these limits the ITT is mandatory and its important role in the recognition of secondary adrenal failure is further confirmed.

Adrenocorticotropic Hormone↗
PubMed1997

Long-term results of treatment for craniopharyngioma in children.

Results of the treatment of 27 children with craniopharyngioma are reported. A subfrontal pterional approach was used in 55.6% of cases, a transsphenoidal and a transcallosal or transcortical approach in 25.9% and 18.5% of cases, respectively. Radical removal was the goal of surgery and was achieved in 70.8% of cases treated as primary surgery. The operative mortality was 3.7% and was due to hypothalamic failure. Most (81.4%) patients were followed up, for a mean of 7 years. Patients were evaluated according to a functional evaluation scale and outcome categories proposed by us. The scale takes account of tumor (recurrences and their eventual evolution); visual functions; endocrine functions (mainly hypothalamic), attainment of endocrine balance and drug regimen; headache; and psychosocial function. Recurrences were observed in 17.6% of patients treated with radical surgery and in 42.8% of those treated with limited surgery plus radiotherapy. A progressive amelioration of visual, endocrine and neuropsychosocial functions from the intervention to follow-up was observed in the majority of patients. Complete tumor excision was associated in 85% of cases with a low score on the functional scale, reflecting a high functional performance. Adequate substitution therapy maintained endocrine balance in 81% of patients. Since the intervention a progressive decrease in the number and dosages of medications has been observed. The majority of patients were again able to lead a normal social life. Small stature, obesity, headache, and emotional and sexual disturbances were frequent cause of long-term disability even despite adequate drug regimens. The functional evaluation scale we propose is a simple and effective tool that can be easily used during routine evaluation of patients with craniopharyngioma.

Adolescent↗
PubMed1997

Effect of desmopressin on ACTH and cortisol secretion in states of ACTH excess.

OBJECTIVE: To assess the ability of desmopressin administration to stimulate ACTH/cortisol secretion in patients with Cushing's disease, either before or after surgery, and in patients with other states characterized by ACTH hypersecretion, and to compare the results with those obtained after CRH testing. DESIGN AND SUBJECTS: Plasma ACTH and serum cortisol levels were evaluated after the administration of desmopressin (10 micrograms i.v.), CRH (1 microgram/kg i.v.) and saline on different days in 17 patients with Cushing's disease, 1 with occult ectopic ACTH syndrome, 5 with Addison's disease, 3 who had been bilaterally adrenalectomized for Cushing's syndrome and 4 normal subjects. After pituitary adenomectomy desmopressin and CRH were administered again to 13 of the patients who had undergone pituitary surgery for their Cushing's disease. RESULTS: In 16 patients with Cushing's disease with microadenoma a positive ACTH/cortisol rise occurred in 11 patients after both desmopressin and CRH, 2 other patients were responsive only to desmopressin and 2 only to CRH, while in 1 patient equivocal responses to both tests were found. The persistence of a hormonal response to desmopressin after pituitary adenomectomy for Cushing's disease correlated with unsuccessful surgery, while, contrary to CRH, absent ACTH/cortisol rises were found in cured patients 1 and 12 months after operation. In 1 patient suspected for ectopic ACTH hypersecretion, desmopressin and CRH administration did not cause any ACTH/cortisol rise. Significant ACTH rises occurred after both desmopressin and CRH testing in patients with Addison's disease. All the 3 patients adrenalectomized for Cushing's syndrome showed a rise of ACTH levels after CRH, while a similar response after desmopressin occurred in only one of them. CONCLUSIONS: Desmopressin is able to stimulate ACTH and hence cortisol release in Cushing's disease. It may be a useful test in patients with doubtful responses to CRH test, in those exhibiting responses to CRH indistinguishable from those of normal subjects and in the postoperative follow-up of Cushing's disease. In some patients with abolished or reduced cortisol feed-back at hypothalamic-pituitary level the sensitivity of normal corticotrophs to desmopressin is enhanced.

ACTH Syndrome, Ectopic↗
PubMed1997

Loperamide test: a simple and highly specific screening test for hypercortisolism in children and adolescents.

The overnight dexamethasone (DXM) test can give false-positive results in a few conditions (e.g. stress, strenuous exercise, depression, anorexia, anxiety, anticonvulsive therapy) in diagnosing simple obesity and hypercortisolism (HC). The loperamide (LP; a peripheral opioid agonist) test has proven useful in such conditions in adults. Thirty-one obese subjects (age 10.0-19.7 y) were studied by both overnight DXM test and LP test (8 mg orally, samples for cortisol at 0, 90, 150, 180 and 210 min) on 2 separate days. LP suppressed cortisol (< or = 138 nmol l-1) at a dose of 0.1 mg kg-1 bw (half the minimum recommended dose for the drug's antidiarrhoea effect) in 14 subjects who had normal urinary (< 4970 nmol l-1) and serum (< 552 nmol l-1) cortisol, in the absence of signs and symptoms of HC (group A). The DXM test failed to suppress cortisol in three subjects in group A, two of whom were on anticonvulsive treatment. The LP test suppressed cortisol in all of 13 subjects with elevated urinary and/or serum cortisol and/or with signs or symptoms of HC (but in whom HC was subsequently excluded on clinical grounds) (group B), while the DXM test failed to suppress cortisol in three subjects of this group. One of these was under anticonvulsive treatment and one suffered from anxiety and depression. In four patients with Cushing's syndrome (group C) neither DXM nor LP could suppress cortisol levels. Therefore, the sensitivity was 100% for both DXM and LP, while the specificity was 84% for DXM and 100% for LP. No side-effects were observed with either drug. In conclusion, LP is a useful alternative to DXM in those particular conditions that can affect its specificity in children.

Adolescent↗
PubMed1996

Modifications of biochemical markers of bone and collagen turnover during corticosteroid therapy.

Serum bone Gla protein (BGP), carboxyterminal cross-linked telopeptide of type I collagen (ICTP) and aminoterminal propeptide of type III procollagen (PIIINP) levels were determined in 8 patients with autoimmune disorders (2 with systemic lupus erythematosus, 3 with rheumatoid arthritis, 2 with Sjögren's syndrome and 1 with mixed connective tissue disease) before and after 1, 2 and 4 months of treatment with oral prednisone (at a dosage of 1 mg/kg bw/day, p.o. during the first month, then reduced to 0.1-0.2 mg/kg bw/day). Before treatment mean serum BGP (mean +/- SE: 5.3 +/- 0.4 ng/ml) and ICTP (2.8 +/- 0.2 ng/ml) levels were similar to those recorded in an age and sex matched control group (n = 40: 5.4 +/- 0.1 ng/ml and 4.1 +/- 0.3 ng/ml, respectively). On the other hand, serum PIIINP levels (2.2 +/- 0.3 ng/ml) were significantly (p < 0.008) lower than those found in controls (3.3 +/- 0.2 ng/ml). During glucocorticoid therapy, serum BGP levels significantly decreased after 1 month (2.9 +/- 0.4 ng/ml; P < 0.001), but returned to baseline values after 2 and 4 months of treatment (4.7 +/- 0.4 ng/ml and 5.3 +/- 0.3 ng/ml, respectively). On the contrary, no significant changes were observed in serum ICTP levels during treatment (1st month: 2.7 +/- 0.4 ng/ml; 2nd month: 3.0 +/- 0.4 ng/ml; 4th month: 2.4 +/- 0.3 ng/ml). Serum PIIINP mean concentration significantly decreased after 1 (1.6 +/- 0.3 ng/ml; P < 0.004) and 2 months of glucocorticoid administration (1.5 +/- 0.2 ng/ml; P < 0.01); after 4 months, serum PIIINP levels were again reduced as before therapy (1.8 +/- 0.2 ng/ml). In conclusion, our study shows the presence of normal bone turnover indexes and of altered collagen synthesis in patients with autoimmune disorders. The use of high doses of oral steroids is associated with a prompt decrease of bone formation and collagen synthesis, without any significant changes in bone resorption; however, the negative effects on bone formation and collagen synthesis seem to revert after lowering corticosteroid dosage. Serial determinations of the markers of bone and collagen turnover are able to give useful and reliable information on the peripheral effects of steroids excess.

Adult↗
PubMed1996

Value of buserelin testing in the evaluation of hirsute women.

It has been recently reported that many hirsute women are affected with functional ovarian hyperandrogenism (FOH)-a term that encompasses the heterogeneous polycystic ovary syndrome- and show an abnormal ovarian steroidogenic response to gonadotropin-releasing hormone (Gn-RH) agonists. The aims of the present study were to determine the prevalence of FOH by the assessment of 17-hydroxyprogesterone (17-OHP) response to the Gn-RH agonist buserelin, to correlate these abnormal responses to other parameters suggestive of PCOS, and to assess the possible adrenal origin of hyperandrogenism. Therefore, in 33 consecutive women with hirsutism serum LH, FSH, 17-OHP, dehydroepiandrosterone sulfate (DHEA-S), androstenedione (A), cortisol levels were evaluated in basal conditions and after the administration of buserelin (0.5 mg sc) and ACTH (tetracosactide 0.25 mg iv). Two patients were affected with a non classic congenital adrenal hyperplasia (CAH)-21OH deficiency. In 5 other women ACTH test caused a rate increase 17-OHP (30-0)/30 min > 19 nmol/L/min (0.25 +/- 0.03; mean +/- SE), suggesting the possible existence of heterozygote non classic CAH-21OH. One patient showed a DHEA-S response to ACTH (from 10.3 to 17.2 mumol/L), which was compatible with late-onset 3 beta-Hydroxy-delta 5 steroid dehydrogenase deficiency. Out of the 25 patients with normal responsiveness to ACTH, 11 women (group A) showed higher 17-OHP and A levels, in comparison to normal women, both in basal conditions (17-OHP = 4.18 +/- 0.72 vs 1.74 +/- 0.34 nmol/L, p < 0.005; A = 11.8 +/- 1.2 vs 6.0 +/- 0.7 nmol/L, p < 0.05) and after buserelin (17-OHP = 15.61 +/- 1.31 vs 6.96 +/- 0.9 nmol/L; A = 19.0 +/- 1.9 vs 7.5 +/- 0.8 nmol/L; p < 0.001). In 6 of these 11 patients basal and buserelin-stimulated LH levels were higher than in normals. The remaining 14 patients (group B) showed normal baseline and buserelin-stimulated 17-OHP and A concentrations. In this group only 2 patients had high basal and stimulated LH levels. An augmented LH/FSH ratio was present in 5 and 1 cases of groups A and B, and polycystic ovaries at ultrasonography were observed in 7 and 8 cases of groups A and B, respectively. It is to note that an abnormal 17-OHP response to buserelin was present also in 3 of the 5 patients with abnormal 17-OHP rise after ACTH test, suggesting an adrenal and ovarian cause of hyperandrogenism. In conclusion, an abnormal response to one or both stimulation test was present in 57% of cases: an adrenal origin of hirsutism was detected in 15%, a combined adrenal and ovarian origin was found in 9% and an ovarian cause was present in 33%. Buserelin testing is an useful means to reveal the presence of FOH.

17-alpha-Hydroxyprogesterone↗
PubMed1996

Serum bone Gla protein and carboxyterminal cross-linked telopeptide of type I collagen in patients with Cushing's syndrome.

Serum bone Gla protein, a marker of bone formation, and carboxyterminal cross-linked telopeptide of type I collagen levels, an index of bone resorption, were evaluated in eight patients with active Cushing's syndrome and in four with 'preclinical' Cushing's syndrome, before and after surgery. In basal conditions, serum bone Gla protein levels were significantly lower (p < 0.0001) in patients with active Cushing's syndrome (1.0 +/- 0.35 ng/ml) than in controls (5.4 +/- 0.15 ng/ml); two out of four patients with the 'preclinical' form had reduced bone Gla protein levels, while in the other two cases levels were in the normal range. Serum levels of carboxyterminal cross-linked telopeptide of type I collagen (3.0 +/- 0.4 ng/ml), although slightly reduced, were similar to those recorded in controls (4.1 +/- 0.3 ng ml), both in patients with active and with preclinical Cushing's syndrome. After surgery serum levels of both marker proteins significantly increased in seven out of eight patients with active Cushing's syndrome; in one patient, who was not cured after surgery, bone Gla proteins levels remained lower than in normals, while levels of carboxyterminal cross-linked telopeptide of type I collagen had a transient increase after six months. In the two patients with a 'preclinical' Cushing's syndrome who underwent surgery, a significant rise of the levels of both marker proteins was observed, similar to that observed in patients with active Cushing's syndrome. It was concluded that serial determinations of these new markers of bone formation and resorption may be usefully employed to follow-up the clinical course of Cushing's syndrome and provide information on the rate of bone turnover in response to medical and/or surgical therapies. Moreover, the evaluation of these markers in preclinical states of Cushing's syndrome might suggest the need for surgery.

Adult↗
PubMed1995

Abnormalities of endocrine function in patients with clinically "silent" adrenal masses.

Because, in recent years, patients with incidentally discovered adrenal masses have been encountered increasingly, their endocrine function was investigated in basal conditions and after dynamic tests. Thirty-two patients (23 women and 9 men, aged 28-74 years) were studied. Lesion diameter, as documented by computed tomography and/or nuclear magnetic resonance imaging, ranged between 5 and 65 mm; the tumors were localized on the right in 22 patients, on the left in 5 and bilaterally in 5 cases. In basal conditions, urinary free cortisol (UFC) excretion, plasma adrenocorticotropin (ACTH) and cortisol levels were normal, except for 4 patients who showed high UFC and ACTH levels in the low-normal range. Ovine corticotropin-releasing hormone (CRH, 1 microgram/kg iv) was given to 18 patients, inducing normal ACTH and cortisol responses in 12, blunted responses in 4 and no response in 2 cases. No reduction in ACTH and cortisol levels after suppression tests was observed in 4 of 29 patients after dexamethasone (1 mg overnight) or in 6 of 29 after loperamide. The 4 patients who were unresponsive to both tests did not show any further inhibition after high-dose dexamethasone administration, had low plasma ACTH levels and showed impaired or absent responses to the CRH test: they were diagnosed as affected with preclinical Cushing's syndrome. An exogenous ACTH test performed in 30 patients caused a normal cortisol rise. Basal mean 17-hydroxy-progesterone (17-OHP) levels were not different from those in normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

17-alpha-Hydroxyprogesterone↗
PubMed1995

[Clinical and preclinical aspects of adrenal Cushing syndrome].

Cushing's syndrome of adrenal origin encompasses different entities: besides the occurrence of adenoma and carcinoma, a not homogeneous group includes the ACTH-independent macro- or micronodular bilateral hyperplasia and the familial pigmented nodular hyperplasia (Carney's syndrome). Moreover, isolated cases of immunological origin and food-dependence have recently described. On clinical grounds no major characteristics may help to identify the adrenal origin of Cushing's syndrome, except for few situations as carcinoma or nodular dysplasia. Laboratory investigations of patients with adrenocortical tumor are based on ACTH and cortisol determinations in basal conditions and in response to high dose dexamethasone and CRH tests. However, isolated diagnostic problems may occur, as the presence of a black adrenocortical adenoma or the uncommon persistence of a circadian rhythmicity of glucocorticoid secretion. The evaluation of new markers of bone turnover (BGP, ICTP) and of collagen turnover (PIIINP) confirms the existence of corticosteroid-induced bone and collagen damages and may also be a useful prognostic index after treatment. Although up to now food-dependent Cushing's syndrome appears to be very rare, the adrenocortical sensitivity to GIP has been investigated in patients with either pituitary Cushing's disease, or clinically silent adrenal masses. No evidence of GIP-dependent cortisol secretion during the peptide infusion or after endogenous stimulation by OGTT was observed in any case. Since the wide availability of sensitive and noninvasive imaging techniques (CT and NMR), in recent years the finding of incidentalomas has become fairly common. In patients with incidentaloma abnormalities of the endocrine function are frequently encountered, and the "preclinical" Cushing's syndrome is increasingly recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1994

Effect of atrial natriuretic factor infusion on basal and CRH-stimulated ACTH, cortisol and aldosterone levels in patients with Cushing's or Addison's disease.

OBJECTIVE: While it has been shown that atrial natriuretic factor (ANF) is able to inhibit CRH-stimulated ACTH secretion in vitro, in normal men conflicting results on its effect on ACTH/cortisol responses to insulin and CRH have been reported. Since no data are available concerning the possible influence of ANF on the hypothalamic-pituitary-adrenal axis in states of ACTH hypersecretion, the effect of ANF on pituitary-adrenal function in basal conditions and after CRH stimulation has been investigated in patients with Cushing's (n = 4) and Addison's disease (n = 4). DESIGN: On two different days all patients underwent the following procedures: (a) alpha-human ANF was infused, after a priming dose of 100 ng i.v., at a rate of 0.01 microgram/kg/min over 5 hours. After 120 minutes of ANF infusion, oCRH (1 microgram/kg) was i.v. injected as a bolus; (b) vehicle infusion was given over 5 hours and at 120 minutes oCRH was injected. Plasma ANF, ACTH, cortisol, aldosterone, renin activity and K+ were measured; heart rate and blood pressure were monitored. RESULTS: In Cushing's disease plasma ANF rapidly increased within 30 minutes of the exogenous peptide infusion (from 27 +/- 5 to 73 +/- 14 pmol/l; mean +/- SE), whereas in the vehicle study its concentration was unchanged. During the first 2 hours of both tests no significant modifications in ACTH levels were observed. After CRH the plasma ACTH peak was unchanged. Serum cortisol levels progressively declined during the first 2 hours of ANF infusion (from 778 +/- 150 to 461 +/- 48 nmol/l; P < 0.05), whereas no changes were observed during vehicle. After CRH serum cortisol rose to similar peaks. Plasma aldosterone levels were significantly reduced during the first 2 hours of ANF infusion (from 81 +/- 20 to 35 +/- 7 pmol/l P < 0.05), whereas no changes were found during vehicle. A similar aldosterone rise was induced by CRH during either vehicle or ANF. Mean plasma renin activity slightly declined and the changes were similar on both occasions. In Addison's disease ANF levels rose within 30 minutes of the peptide infusion (from 12 +/- 1 to 49 +/- 8 pmol/l), while they were unchanged during vehicle. A slight decline in ACTH levels in the first 2 hours was observed during either vehicle or ANF infusion. After CRH the plasma ACTH peaks were similar. Mean plasma renin activity was unaffected by vehicle, while ANF caused a decline during the first 2 hours (from 13.4 +/- 0.8 to 7.7 +/- 0.3 ng/ml/h). In all patients, heart rate, blood pressure and K+ were only slightly affected on both occasions. CONCLUSIONS: (1) In patients with corticotrophin hypersecretion ANF does not influence basal and CRH-stimulated ACTH secretion; (2) in Cushing's disease ANF inhibits cortisol and aldosterone basal secretion; this effect is not mediated by ACTH and is over-ridden by CRH stimulation.

Addison Disease↗