Adrenal insufficiency as the first clinical manifestation of the primary antiphospholipid antibody syndrome.

We describe a 60-year-old man who developed clinical symptoms and signs of Addison's disease, which was subsequently confirmed biochemically; no cause was apparent. Several months later the patient represented with a fit, followed by a large and extensive venous thrombosis in the right iliac vein and in the veins of the right leg. He had strongly positive antibodies to cardiolipin, strongly suggesting a diagnosis of primary antiphospholipid syndrome. While Addison's disease is a well-recognized, albeit rare, manifestation of the antiphospholipid syndrome, the Addison's disease preceded other clinical evidence of the syndrome by several months, in our patient, at variance with previous cases described in the literature. The antiphospholipid syndrome should be considered as a possible pathogenetic process in patients presenting with Addison's disease where the aetiology is not obvious.

Membrane receptors and hormones.

The regulation of metabolic processes, cell growth and differentiation is achieved by an interaction between hormones and specific cellular binding sites termed "receptors". These may be located on the cellular surface, in the cytoplasm or in the nucleus. Recently the structure of several membrane receptors in mammalian cells have been elucidated. These consist of peptide chains possessing multiple functional "domains". We describe in details the extracellular, transmembrane and intracellular "domains". In recent years antibodies to many receptors and analogues of some peptide hormones have become available; these can be used in clinical practice to study receptors, their localization and, in some cases, to block their function.

Dexamethasone inhibition of interferon-alpha 2-induced stimulation of cortisol and growth hormone secretion in chronic myeloproliferative syndrome.

This study investigated the acute effects of interferon-alpha 2 (IFN-alpha 2) on hormonal secretion in adult patients affected by a chronic myeloproliferative syndrome and tried to shed some light on the mechanism by which IFN-alpha 2 stimulates cortisol and GH secretion in humans. We compared the pattern of IFN-alpha 2-induced cortisol and GH release with that elicited after the same challenge given subsequent to pretreatment with dexamethasone (Dex). We studied eight patients affected by a chronic myeloproliferative syndrome (thrombocythemia) who had been selected for treatment with IFN-alpha 2. Four sets of experiments were performed: 1) 2 mL iv saline was given at 0800 h in eight cases; 2) 3 x 10(6) IU iv IFN-alpha 2 was given at 0800 h in eight cases; 3) 3 x 10(6) IU iv IFN-alpha 2 was given at 0800 h after pretreatment with 1.5 mg Dex (1 mg at midnight the previous night and 0.5 mg at 0700 h on the day of the test) in six cases; and 4) 2 mL iv saline was given at 0800 h after the same Dex pretreatment in four cases. Cortisol and GH were measured in plasma samples drawn at 30-min intervals between 0800 and 1300 h. Acute iv administration of IFN-alpha 2 stimulated the release of both cortisol and GH in each patient with a significant increment vs. control values, as assessed by areas under the curve. The administration of Dex significantly decreased basal plasma cortisol secretion and abolished cortisol response to IFN-alpha 2 administration. These data suggest that the stimulatory action of IFN-alpha 2 on cortisol release is mediated via a modulation of the activity of the hypothalamic-pituitary axis rather than through a direct effect at the level of the adrenal cortex. After Dex plus saline administration, no significant effect was observed on plasma GH levels, which remained low. Dex administration significantly decreased GH response to IFN-alpha 2. These data suggest that a hypothalamic or pituitary stimulation (or both) is involved in the mechanism of IFN-alpha 2-induced GH secretion. It remains to be established whether IFN-alpha 2 directly stimulates pituitary somatotropic cells or whether the cytokine exerts a stimulatory action on GH secretion by indirectly modulating the hypothalamic or pituitary activity. In conclusion, acute iv administration of IFN-alpha 2 represents a potent stimulus for cortisol and GH secretion in adult human subjects.(ABSTRACT TRUNCATED AT 400 WORDS)

Incidentally discovered adrenal masses: a functional and morphological study.

In the last two years we have examined 17 consecutive patients (11 females and 6 males, 20-66 years old) in whom an unsuspected adrenal mass was discovered by ultrasonography or computed tomography performed for unrelated reasons. Pathological diagnosis was available in 11 cases based on surgical excision in 9 (2 pheochromocytomas of 5 and 12 cm in diameter; 2 ganglioneuromas of 5 and 6 cm; and 5 benign cortical adenomas between 3 and 5 cm), autopsy in 1 (a disseminated malignant pheochromocytoma of 16 cm) and fine-needle biopsy in 1 (a pseudo-adrenal mass of 6 cm, that was a regenerative hepatic nodule). The remaining 6 non histologically diagnosed masses were less than 3 cm in diameter. Endocrine studies showed elevated urinary excretion of catecholamines, vanillylmandelic acid and metanephrines in the pheochromocytomas and borderline high values in ganglioneuromas. A low plasma renin activity was encountered in 2 operated cortical adenomas and 3 non operated incidentalomas. In 2 of the latters aldosterone serum levels were elevated and the final diagnoses respectively were Conn's adenoma and dexamethasone-suppressible hyperaldosteronism with bilateral nodular hyperplasia. An inappropriate cortisol secretion was documented in a cortical adenoma removed. Radio-cholesterol scintiscan showed unilateral or increased uptake on the side of adrenal mass (concordant uptake) in the 5 benign cortical adenomas removed and in 4 non operated incidentalomas. A decreased uptake on the side of the adrenal mass (discordant uptake) was found in the 2 ganglioneuromas while an indeterminate bilateral uptake was found in the 2 remaining non operated incidentalomas and in the pseudo-adrenal mass.(ABSTRACT TRUNCATED AT 250 WORDS)

Corticotropin-releasing hormone inhibition of paradoxical growth hormone response to thyrotropin-releasing hormone in insulin-dependent diabetics.

A paradoxical growth hormone (GH) response to thyrotropin-releasing hormone (TRH) has been observed in type 1 diabetic patients and was hypothetically attributed to a reduced hypothalamic somatostatin tone. We have previously reported that corticotropin-releasing hormone (CRH) inhibits GH response to growth hormone-releasing hormone (GHRH) in normal subjects, possibly by an increased release of somatostatin. To study the effect of CRH on anomalous GH response to TRH, we tested with TRH (200 micrograms intravenously [IV]) and CRH (100 micrograms IV) + TRH (200 micrograms IV) 13 patients (six males and seven women) affected by insulin-dependent diabetes mellitus. A paradoxical GH response to TRH was observed in seven of 13 patients, one man and six women. In these subjects, the simultaneous administration of CRH and TRH significantly reduced the GH response to TRH, as assessed by both the maximal GH mean peak +/- SE (2.18 +/- 0.67 v 9.2 +/- 1.26 micrograms/L, P less than 0.005) and the area under the curve (AUC) +/- SE (187 +/- 32 v 567 +/- 35 micrograms.min/L, P less than .001). CRH had no effect on TRH-induced thyroid-stimulating hormone (TSH) release. Our data demonstrate that the paradoxical GH response to TRH in patients with type 1 diabetes mellitus is blocked by CRH administration. This CRH action may be due to an enhanced somatostatin release. Our data also show that exogenous CRH has no effect on TSH response to TRH, thus suggesting the existence of separate pathways in the neuroregulation of GH and TSH secretion.

Effects of sex and age on pyridostigmine potentiation of growth hormone-releasing hormone-induced growth hormone release.

Previous studies have shown that pyridostigmine (PD) is capable of increasing the growth hormone (GH) response to GH-releasing hormone (GHRH) in young healthy subjects. In order to investigate the influence of age and sex on the PD potentiation of GHRH-induced GH release, we have studied the GH response to GHRH (50 micrograms i.v.) 1 h after oral administration of placebo or PD (60 mg) in 8 young healthy men (aged 19-28 years) and 8 age-matched young women (aged 18-25 years) during the follicular phase of the menstrual cycle, as well as in 8 postmenopausal women (aged 57-62 years) and 8 age-matched elderly men (aged 56-64 years). In the same subjects the effect of PD alone (60 mg p.o.) was also studied. Furthermore, in 6 postmenopausal women and 6 elderly men, the effect of a 30-mg PD oral dose on GH secretion and GH response to GHRH was evaluated with a similar protocol. The GH responses (mean +/- SE) to GHRH + placebo were similar in young men (peak 20.1 +/- 2 ng/ml, AUC 1,250 +/- 113 ng/ml/min) and women (peak 29.3 +/- 2.3 ng/ml, AUC 1,769 +/- 305 ng/ml/min). PD 60 mg was capable of significantly increasing the GH response to GHRH in young men (peak 43.5 +/- 5.1 ng/ml, AUC 3,734 +/- 472 ng/ml/min, p less than 0.005) but not in women (peak 39 +/- 2.3 ng/ml, AUC 2,479 +/- 205 ng/ml/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Activation of cholinergic tone by pyridostigmine reverses the inhibitory effect of corticotropin-releasing hormone on the growth hormone-releasing hormone-induced growth hormone secretion.

Previous studies have shown that corticotropin-releasing hormone (CRH) is capable of inhibiting growth hormone (GH) secretion in response to GH-releasing hormone (GHRH). In an attempt to clarify the mechanism of the CRH action, we have studied the effect of enhanced cholinergic tone induced by pyridostigmine on the CRH inhibition of the GH response to GHRH in a group of six normal men and six normal women. All subjects presented a normal GH response to 50 micrograms i.v. GHRH administration (mean peak +/- SEM plasma GH levels 20 +/- 2.9 micrograms/l in men and 28.9 +/- 2.9 micrograms/l in women) with a further significant increase after pyridostigmine pretreatment (60 mg orally given 60 min before GHRH) in men (GH peaks 43.1 +/- 6.9 micrograms/l, p less than 0.005) but not in women (GH peaks 39.2 +/- 3.0 micrograms/l). In the same subjects, peripherally injected CRH (100 micrograms) significantly inhibited the GH response to GHRH (GH peaks 8.1 +/- 0.6 micrograms/l in men, p less than 0.005 and 9.9 +/- 0.7 micrograms/l in women, p less than 0.005). Pyridostigmine (60 mg) given orally at the same time of CRH administration (60 min before GHRH) reversed the CRH inhibition of GHRH-induced GH secretion (GH peaks 35.3 +/- 8.2 micrograms/l in men and 35 +/- 3.3 micrograms/l in women) with a response not significantly different to that seen in the pyridostigmine plus GHRH test. Our data confirm that pyridostigmine is capable of potentiating the GHRH-induced GH release in normal male but not female subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute complications in the course of "mild" hyperparathyroidism.

It is generally accepted that some patients affected by mild asymptomatic primary hyperparathyroidism need not be treated with surgery, but may be medically managed without risk. However, our experience regarding 5 of these cases observed in the last two years, suggests a different approach. These patients, initially diagnosed as having mild hyperparathyroidism based on only moderately elevated serum concentrations of calcium and followed medically for years, were referred to us for a sudden worsening of their clinical course. One 35-year-old man presented hemorrhagic gastritis with severe anemia and type II AV block with syncopal attacks. Three women, aged 51, 64 and 65 years, presented with severe hypercalcemia associated with renal failure in two and with marked bone disease in another. In all these cases parathyroid neoplasms were preoperatively localized (by ultrasonography, CT scan and radioactive 201-Tl 99-Tc scan) and surgically removed. Histological examination showed a parathyroid carcinoma in the male patient and single gland enlargements in the three females. A fifth patient, a 65-year-old woman, was referred to us in critical condition: severe hypercalcemia, osteopenia with femur fracture, myocardial infarction and renal failure. She died in a few days, in spite of intensive medical care. These cases suggest that patients with hyperparathyroidism initially diagnosed as "mild" need close medical observation and preferably, in our opinion, should undergo surgery.