Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of the defining biochemical features of Cushing's disease is a relative insensitivity to glucocorticoid (GC) feedback, but an analysis of the GC receptor has failed to detect any major abnormalities. However, two isoenzymes of 11 beta-hydroxysteroid dehydrogenase (11 beta HSD), either by converting cortisone (E) to cortisol (F) (type 1) or conversely by converting F to E (type 2), play an important prereceptor role in regulating corticosteroid hormone action at several sites. 11 beta HSD1 and -2 expression within the anterior pituitary gland itself may modulate GC feedback at an autocrine level, and we have speculated that this may be deranged in Cushing's disease. Detection of 11 beta HSD type 1 and 2 immunoreactive protein was performed using fluorescence immunohistochemistry. Double immunofluorescent studies were undertaken on normal pituitary to define the cellular localization of 11 beta HSD isoenzymes using antisera against GH, ACTH, LH, FSH, PRL, and S100, a nonhormonal marker of folliculo-stellate cells. In normal pituitary, positive staining for 11 beta HSD1-immunoreactive protein was observed in GH- and PRL-secreting cells and in folliculo-stellate cells; gonadotrophs, thyrotrophs, and ACTH-positive cells were negative. 11 beta HSD2 immunoreactivity was absent in all cell types. RT-PCR detected 11 beta HSD1 messenger ribonucleic acid (mRNA) expression in the normal pituitary; 11 beta HSD2 mRNA expression was also seen in most normal tissue. By contrast, in ACTH-secreting adenomas 11 beta HSD2 immunostaining was strongly positive in every case of corticotroph adenoma. 11 beta HSD1 immunoreactivity was also observed occasionally, but to a much lesser extent. In other pituitary tumors, both functional and nonfunctional, 11 beta HSD expression was variable in terms of isoenzyme mRNA and intensity of protein staining. The expression of 11 beta HSD1 (which generates F from E) in somatotrophs and lactotrophs suggests an autocrine role for this isoenzyme in the glucocorticoid regulation of pituitary GH and PRL secretion. 11 beta HSD2 expression is markedly induced in ACTH-secreting pituitary tumors and, by converting F to E, may explain the resetting of glucocorticoid feedback control in Cushing's disease.
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PMID:Expression of 11 beta-hydroxysteroid dehydrogenase isoenzymes in the human pituitary: induction of the type 2 enzyme in corticotropinomas and other pituitary tumors. 1139 78

Cushing's syndrome invariably presents with a classical phenotype comprising central adiposity, prominence of dorsal, supraclavicular and temporal fat pads, bruising, abdominal striae, proximal myopathy, and hypertension. We report the case of a 20-yr-old student with pituitary-dependent Cushing's syndrome who was spared this classical phenotype because of a defect in the peripheral conversion of cortisone to cortisol. She presented to her general practitioner with secondary amenorrhea. Clinical examination revealed normal fat distribution (body mass index, 20.9 kg/m(2)), absence of hirsutism, myopathy, or bruising; her blood pressure ranged from 115/70 to 122/82 mm Hg. She was investigated for biochemical hypercortisolemia because of a mildly elevated random circulating cortisol (serum cortisol, 661 nmol/liter). Cushing's syndrome was confirmed on the basis of repeatedly elevated urinary free cortisols (831-1049; reference range, <350 nmol/24 h), failure of low-dose dexamethasone suppression (611 nmol/liter) and loss of circadian cortisol secretion. Investigations suggested Cushing's disease; there was suppression after high-dose dexamethasone (<20 nmol/liter) and a 950% increase in ACTH after stimulation with CRH. Pituitary magnetic resonance imaging revealed a 3-mm adenoma within the pituitary gland. Urinary corticosteroid metabolites were analyzed by gas chromatography-mass spectrometry and demonstrated a decreased THF+allo-THF/THE ratio of 0.66 (mean +/- SE in Cushing's disease, 1.74 +/- 0.24) suggesting a defect in 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), an enzyme that converts the inactive glucocorticoid cortisone to active cortisol. Transphenoidal microadenomectomy was performed, and histology confirmed the diagnosis of a corticotroph adenoma. Postoperatively, serum cortisol was undetectable and replacement therapy was commenced. Subsequent investigations revealed a significantly impaired ability to convert an oral dose of cortisone acetate (25 mg) to cortisol, reduced serum cortisol to cortisone ratios, and a reduced serum half-life for cortisol (57.3 min). These results provide strong evidence for a partial defect in 11beta-HSD1 activity and concomitant increase in cortisol clearance rate. We have described a case of Cushing's disease that failed to present with a classical phenotype, and we postulate that this is due to a partial defect of 11beta-HSD1 activity, the defect in cortisone to cortisol conversion increasing cortisol clearance and thus protecting the patient from the effects of cortisol excess. This observation may help to explain individual susceptibility to the adverse effects of glucocorticoids.
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PMID:Absence of Cushingoid phenotype in a patient with Cushing's disease due to defective cortisone to cortisol conversion. 1178 23

Two isozymes of the 11beta-hydroxysteroid dehydrogenase (11-HSD) are responsible for the interconversion of cortisol (F) and cortisone (E). The type 1 isozyme, 11-HSD1, acts mainly as a reductase in vivo, activating E to F, whereas the type 2, 11-HSD2, acts as a dehydrogenase, inactivating F to E. 11-HSD1 is the most abundant in the liver and 11-HSD2 in the kidney. In this study, we attempted to determine which isozyme and organs primarily contribute to equilibrium of plasma F and E concentrations in the peripheral circulation and to clarify differences in 11-HSD activities among adrenocortical disorders. Upon selective catheterizations for adrenocortical and renovascular disorders, plasma F and E concentrations in the femoral vein were closer to those in the renal vein than those in the hepatic vein. Values for mean plasma F/E ratios in the peripheral vein were in-between those of the adrenal and renal veins. A double reciprocal plot between peripheral plasma F and E concentrations in patients with various adrenocortical tumors was almost identical to that in normal subjects. Mean plasma F/E ratio in peripheral blood was higher in patients with Cushing's syndrome and was lower in patients with primary aldosteronism and nonfunctioning adrenocortical adenoma than that in normal subjects. These results suggest that renal 11-HSD2 is a main factor controlling the equilibrium of plasma F and E concentrations in the periphery and that cortisol and aldosterone excess do not change the equilibrium of plasma F and E concentrations in the peripheral circulation, but may alter expression of 11-HSD2. Alternation of 11-HSD2 activities as well as corticosteroid levels may be important in the pathophysiology of adrenocortical disorders.
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PMID:Plasma cortisol and cortisone concentrations in normal subjects and patients with adrenocortical disorders. 1468 48

Cushing's disease is characterized by persistent ACTH secretion under hypercortisolemia. In an attempt to clarify the molecular mechanism, we examined the effect of 11beta-hydroxysteroid dehydrogenase (HSD) inhibition on glucocorticoid suppression of ACTH release using murine corticotroph tumor cells. We found that 11beta-HSD2, as well as -HSD1, was expressed in the cells and that its inhibition by carbenoxolone significantly improved the negative feedback effect of glucocorticoid. Carbenoxolone also enhanced apoptosis induced by cortisol. These effects are most likely attributable to inhibition of 11beta-HSD2 because only cortisol, a substrate of 11beta-HSD2, was present in these experimental conditions. We conclude that ectopic expression of 11beta-HSD2 is, at least in part, responsible for the impaired glucocorticoid suppression in corticotroph adenoma. Inhibition of 11beta-HSD2 may be applicable to the medical therapy for Cushing's disease.
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PMID:Inhibition of 11beta-hydroxysteroid dehydrogenase eliminates impaired glucocorticoid suppression and induces apoptosis in corticotroph tumor cells. 1625 34

This report concerns a case of cortisol-producing adrenocortical adenoma without the phenotype of Cushing's syndrome. A left adrenal tumor was incidentally detected in this patient. A diagnosis of adrenal Cushing's syndrome was based on the results of endocrinological and radiological examinations, although she showed none of the physical signs of Cushing's syndrome, glucose intolerance, hypertension or dyslipidermia. After a successful laparoscopic left adrenalectomy, the pathological diagnosis was adrenocortical adenoma. Slow tapering of glucocorticoids was needed to prevent adrenal insufficiency after surgery, and the plasma ACTH level remained high even though the serum cortisol level had reached the upper limit of the normal range. Further examination showed a urinary THF + allo-THF/THE ratio of 0.63, which was lower than that of control (0.90 +/- 0.13, mean +/- SD). Serum cortisol/cortisone ratios after the cortisone acetate administration were also decreased, and the serum half-life of cortisol was shorter than the normal range which has been reported. These findings indicated a partial defect in 11beta-hydroxysteroid dehydrogenase 1 (11beta-HSD1) activity, which converts cortisone to cortisol. Our case suggests that a change in 11beta-HSD1 activity results in inter-individual differences in glucocorticoid efficacy.
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PMID:A case of cortisol producing adrenal adenoma without phenotype of Cushing's syndrome due to impaired 11beta-hydroxysteroid dehydrogenase 1 activity. 1849 11