The syndrome of primary aldosteronism is characterized by definition by an autonomous hypersecretion of aldosterone (aldo), i.e. independent from the known regulatory factors. In fact, plasma renin activity is suppressed. ACTH levels are normal and serum K potassium levels are low. However, there are two major subtypes of primary hyperaldosteronism (PHA) with different characteristics; in patients with aldosterone-producing adenoma (APA) aldosterone secretion is unresponsive to angiotensin II stimulation, but is still modulated by ACTH; this is reflected in the circadian rhythm of plasma aldosterone levels which parallel cortisol levels, while aldosterone does not respond to upright posture. Furthermore, a transient decrease of aldosterone levels can be obtained by a short-term dexamethasone administration. In the other subtype of PHA, idiopathic hyperaldosteronism (IHA), a certain degree of sensitivity to the renin-angiotensin system persists, as demonstrated by the absence of diurnal rhythmicity, the clear-cut increase of plasma aldosterone after postural stimulation and exogenous
I. KARBOWIAK, G. P. BUZZETTI and F. MANTERO
M. SCHÖNESHÖFER, A. KAGE, B. WEBER, K. NAHOUL and F. MANTERO
U. KUHNLE, D. ARMANINI, F. FALLO, M. WEHLING, H. DÖRR, N. SONINO and F. MANTERO
N M Albiger, P Sartorato, B Mariniello, M Iacobone, I Finco, A Fassina and F Mantero
The mechanisms inducing steroidogenesis in primary aldosteronism (PA) remain poorly defined. It was recently demonstrated that some G-protein-coupled receptors are abnormally expressed in aldosterone-producing adenomas (APA). We evaluated the potential role of LH and GNRH receptors (LHR (or LHCGR) and GNRHR) in regulating aldosterone secretion in a patient with APA arising during pregnancy (index case) and in a subset of other patients with PA.
Patients and methods
GNRH test was performed in the index case, 11 other PA, and 5 controls. GNRHR and LHR expressions were examined in 23 APA and 6 normal tissues.
Aldosterone response increased significantly (114%) in the index case after GNRH test was performed preoperatively, while it was blunted after adrenalectomy. Aldosterone also increased after human chorionic gonadotropin and triptorelin stimulation. A partial aldosterone response to GNRH was observed in other 7/11 PA, while a significant response was observed in two patients. Controls did not respond to GNRH test.
GNRHR was overexpressed and LHR expression was moderate in the APA tissue from the index case. Moreover, LHR was found in normal adrenals and overexpressed in 6/22 APA. GNRHR was overexpressed in 6/22 APA, 2 of them with a 95- and 109-fold higher expression than normal. A correlation between the clinical and molecular findings was observed in five out of seven patients.
We describe a case of PA diagnosed during pregnancy, which appeared to correlate with aberrant LHR and GNRHR expression. Our findings suggest that a subset of patients with PA has aberrant LHR and GNRHR expression, which could modulate aldosterone secretion.
S Filipponi, M Guerrieri, G Arnaldi, M Giovagnetti, AM Masini, E Lezoche and F Mantero
OBJECTIVE: To investigate the feasibility, safety and results of laparoscopic transperitoneal adrenalectomies performed with the patient supine, in patients affected by secreting and silent adrenal lesions. METHODS: Exclusion criteria were suspected adrenal primary malignancies. Fifty patients (33 women and 17 men; mean age 49.6 years, range 19-75 years) underwent 51 laparoscopic adrenalectomies (one bilateral). After complete endocrinological evaluation, computed tomography or magnetic resonance imaging, or a combination thereof, 14 non-secreting adenomas, 13 aldosterone-producing adenomas, 13 cortisol-producing adenomas, eight phaeochromocytomas (one bilateral), one androgen-secreting adenoma, and two metastases were considered eligible for adrenalectomy. In five patients, associated procedures were performed during surgery. RESULTS: The lesions ranged in size from 1.5 to 10 cm. There were no intraoperative complications and no blood transfusions were required. The postoperative course was uneventful and painless in all patients. Mean postoperative hospital stay was 2.5 days. In all hypertensive patients, significant improvement or cure of hypertension was observed at follow-up (mean 18 months). In patients with secreting adenomas, normalization of hormone concentrations was obtained after removal of the tumour. In six patients with incidentaloma, the exaggerated 17-hydroxyprogesterone response to ACTH disappeared after surgery. CONCLUSIONS: Secreting and non-secreting adrenal lesions were treated safely by laparoscopy. Relatively small incidentalomas and subclinical hormonally active tumours can be removed by laparoscopy. Early diagnosis enhances prevention and treatment.
M. Birkhäuser, A. M. Rionde, R. Gaillard, F. Mantero and M. B. Vallotton
The influence of acute stimulation by ACTH, upright posture and angiotensin II on plasma aldosterone levels was assessed in human panhypopituitarism.
While stimulation by ACTH in hypopituitary patients induced a plasma aldosterone increase similar to that observed in healthy controls, stimulation by upright posture or by infusion of angiotensin II resulted in a lower plasma aldosterone response than in controls in most of the patients.
These results suggest that the presence of an anterior pituitary hormone, most likely ACTH, directly or indirectly exerts a permissive action on aldosterone secretion in man.
N M Albiger, G Occhi, B Mariniello, M Iacobone, G Favia, A Fassina, D Faggian, F Mantero and C Scaroni
Cortisol secretion in ACTH-independent macronodular adrenal hyperplasia (AIMAH) may be regulated by the aberrant expression of several G-protein-coupled receptors. Bilateral adrenalectomy is the treatment of choice in most cases. We searched for aberrant receptor expression in a patient with AIMAH and evaluated the response to medical and surgical treatment.
A 35-year-old woman with amenorrhea, hirsutism, and hypertension presented ACTH-independent cortisol secretion with high androgen levels. Abdominal computed tomography showed bilateral adrenal macronodules (4.5 cm right and 1.0 cm left). Scintigraphy with I131-norcholesterol showed bilateral uptake, prevalent on the right side. Several in vivo stimulation tests were assessed before and after treatment and in vitro studies were performed after unilateral adrenalectomy.
Plasma cortisol increased after a standard meal test (60%) and oral glucose loading (147%), and the response was blunted by pretreatment with 100 μg s.c. octreotide. The therapy with long-acting release octreotide (octreotide-LAR) showed an improvement in urinary free cortisol (UFC) levels. Unilateral adrenalectomy was performed and histopathology revealed macronodular AIMAH. Cortisol and androgens increased after perifusion of tumoral tissue with glucose-dependent insulinotropic polypeptide (GIP), and GIP and LH-receptor overexpression was found in both the adrenal nodules and the adjacent cortex. After surgery, UFC and androgen levels normalized followed by clinical improvement.
GIP and LH-receptor expression may coexist in AIMAH, influencing the functional and morphological phenotype. Aberrant hormone receptor expression enables specific pharmacological treatment, but long-term studies are needed to evaluate its real efficacy. Unilateral adrenalectomy may be a safe initial option, particularly for asymmetric bilateral adrenal enlargements.
PP Morosini, A Taccaliti, G Arnaldi, G Simonella, MD Petrelli, V Mancini, R Montironi, M Scarpelli, L Diamanti and F Mantero
Morosini PP, Taccaliti A, Arnaldi G, Simonella G, Petrelli MD, Mancini V, Montironi R, Scarpelli M. Diamanti L, Mantero F. Enhanced expression of transforming growth factor β1 in rat thyroid hyperplasia is thyrotropin induced and time dependent. Eur J Endocrinol 1996:134:373–8. ISSN 0804–4643
Forty-three 8-week-old male Wistar rats were studied to evaluate temporal changes of transforming growth factor β1 TGF-β1) mRNA levels in thyroid tissue during pharmacologically induced goiter. Four rats were treated with purified bovine thyrotropin (TSH; Ambinon, 2 mU/day sc) for 7 days before being sacrificed. Thirty-one were treated with propylthiouracil (PTU), added to their drinking water at a concentration of 0.2 g%, and subsequently were sacrificed as follows: five after 1 week PTU-1): five after 2 weeks PTU-2): five after 4 weeks PTU-4): five after 8 weeks PTU-8): five after 12 weeks (PTU-12). In six rats, after 12 weeks of treatment, PTU was withdrawn for 2 months and subsequently started again in three rats which were sacrificed after 2 weeks (PTU-R); the remaining three rats were sacrificed without any further treatment (PTU-R control). Eight rats (control rats) were never treated and served as controls. After sacrifice, blood was drawn for determination of total thyroxine and the thyroid was excised and subdivided into two lobes. Northern analysis for TGF-β1 was performed in one lobe, while histological and immunohistochemical studies were performed in the other lobe. Gene expression of TGF-β1 was induced in TSH- and PTU-treated rats. In TSH-treated rats TGF-β1 gene expression was less detectable than in PTU-treated rats, where it became evident after 2 weeks and remained through weeks 4–8. Gene expression of TGF-β1 was also seen in PTU-R rats, but not in the control and in the PTU-R control. Immunohistochemical analysis showed a different presence and location for the TGF-β1 protein, which appears to be dependent on the time of exposure to mitogenic stimulus. In conclusion, TGF-β1 is produced in response to both a direct (TSH by itself) and indirect (TSH induced by PTU-induced hypothyroidism) cellular proliferative stimulus and is not linked to an adaptative phenomenon secondary to hypothyroidism. The immunohistochemical location of TGF-β1 within the thyrocytes is influenced by mitogen exposure time. A TGF-β1 immunohistochemical evaluation may be important to define exposure time and activity of goitrogenic stimuli.
Pierpaolo Morosini, Clinica di Endocrinologia, c/o Ospedale Regionale, Via Conca, 60100 Torrette Ancona, Italy
R M Testa, N Albiger, G Occhi, F Sanguin, M Scanarini, S Berlucchi, M P Gardiman, C Carollo, F Mantero and C Scaroni
Objective: The etiological diagnosis of ACTH-dependent Cushing’s syndrome is often a problem. In fact, no endocrine or radiological examination can conclusively distinguish the ectopic from the pituitary source of disease. The aim of our study was to evaluate the role of stimulation and suppression endocrine tests in the diagnostic and therapeutic approach of patients with Cushing’s disease (CD) and negative pituitary magnetic resonance imaging (MRI), considering their post-surgical outcome in comparison with patients with CD and positive MRI.
Patients and methods: We retrospectively analyzed 31 patients (25 women and 6 men, median age 40 ± 15 years) with a confirmed diagnosis of CD who underwent transsphenoidal pituitary surgery by the same neurosurgeon between 2001 and 2005. Preoperative endocrine assessment included corticotropin-releasing hormone (CRH), desmopressin (dDAVP), and overnight 8 mg dexamethasone suppression tests (8-DST) in all patients. Fifteen patients had a normal pituitary MRI and sixteen had a clearly evident pituitary microadenoma. Bilateral inferior petrosal sinus sampling (BIPSS) was performed in patients with discordant biochemical results or with signs and symptoms highly suggestive of an ectopic source of ACTH. Post-surgical median follow-up was 38.4 ± 22.0 months.
Results: Among patients with negative MRI, 60% had concordant positive endocrine tests and underwent neurosurgery without other examinations. BIPSS was performed in three other patients prompted by discordant endocrine tests (negative dDAVP) and in two patients with clinical suspicion of ectopic disease. Among patients with positive MRI, 87% underwent neurosurgery without BIPSS that was performed in two patients because of negative concomitant response to dDAVP and CRH tests. A pituitary adenoma, confirmed by pathological examination, was found in 40 and 81% of patients with negative and positive MRI respectively (P<0.05), corticotroph hyperplasia resulted more frequent in the group with negative MRI. Remission rate was not different between patients with negative and positive MRI (73 and 75% respectively; P=0.61) and between patients with negative MRI who did not undergo BIPSS and patients with positive MRI (P=0.56). The recurrence rate was also similar between groups (P=0.64), but higher, although not statistically different (P=0.07) in patients with corticotroph hyperplasia at histology.
Conclusions: An accurate evaluation of presurgical endocrine tests results enabled us to reduce the number of BIPSS in patients with a negative MRI without any fallout on their post-surgical outcome. In the hands of an expert pituitary surgeon, the outcome after surgeryand the subsequent recurrence rate are much the same in patients with negative or positive MRI.