Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.23.15 (renin)
35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adrenocortical causes of hypertension are established by examining the mineralocorticoid hormones produced in the zona glomerulosa and zona fasciculata. In the zona glomerulosa, aldosterone excess leads to hypertension, hypokalemia, and suppressed plasma renin activity, with increased concentrations of urinary aldosterone (either as the 18-glucuronide or free aldosterone) as an index of its production. Identifying a tumor by computed tomography scan verifies the diagnosis of a correctable lesion. If no tumor is found, several maneuvers are used to identify primary adrenal hyperplasia, a disorder with autonomous aldosterone production, for which reduction of adrenal mass is curative. The zona fasciculata has two major pathways: the 17-deoxy pathway, where deoxycorticosterone (DOC) and corticosterone are the significant steroids, and the 17-hydroxy pathway, which leads to cortisol production. Tumors of the 17-deoxy pathway, DOC-producing adenomas, have increased concentrations of DOC and its precursor steroids, normal concentrations of cortisol, and suppression of aldosterone production secondary to suppression of the renin system. Two enzymatic defects in the zona fasciculata, 11 beta- and 17 alpha-hydroxylase deficiency, can be first readily identified by the virilization in the former, hypogonadal features in the latter. Steroid patterns are diagnostic. DOC is produced in excess in both deficiencies and is the cause of the hypertension. Deficient or impaired 11 beta-hydroxy steroid dehydrogenase in the apparent mineralocorticoid excess syndrome or after licorice ingestion retards the conversion of cortisol to inactive cortisone in the kidney, leading to mineralocorticoid hypertension; this leads to suppression of the renin system and subsequently of aldosterone.
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PMID:Steroid characteristics of mineralocorticoid adrenocortical hypertension. 191

A case of left adrenal adenoma with bilateral testicular Leydig cell tumor in a 38-year-old man is reported. He had received bilateral orchiectomy for testicular Leydig cell tumor at the age of 37. After operation computed tomography revealed left adrenal mass and aldosterone-secreting adrenal tumor was suspected. Left adrenalectomy was performed and histopathological diagnosis was adrenocortical adenoma. Serum ACTH, aldosterone and plasma renin activity were still high after operation. The adrenal cortex and gonads are of common embryologic origin and the histologic pattern may overlap. Examination of the adrenal gland is necessary for the patient with a testicular Leydig cell tumor.
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PMID:[Adrenal adenoma with bilateral testicular Leydig cell tumor: a case report]. 195 32

A 37-year-old woman presented with hyperaldosteronism, suppressed renin levels, and a left adrenal mass on CT scanning. Selective adrenal venous sampling indicated a marked rise of the aldosterone level in the right adrenal vein, while the level in the left vein was low. On laparotomy, an aldosterone producing adenoma (APA) of 12x10x5 mm in size was found in the right adrenal gland and was resected, while the left mass was left in situ. The post-operative course showed normalization of both the clinical and biochemical features of primary aldosteronism, with no sign of recurrence or of enlargement of the remaining adrenal mass in 2.5 years of follow up, suggesting the possible coexistence of a "non-functioning" tumor. This case demonstrates the importance of adrenal venous sampling for the localization of APA particularly since the presence of the APA may be masked by a visualized but unrelated adrenal mass.
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PMID:Possible association of aldosterone producing adenoma and non-functioning adrenal tumor. 272 41

Patients with primary aldosteronism do not have distinctive clinical features. However, the associated hypertension is invariably high and often resistant to drug therapy. The recommended initial test in suspected primary aldosteronism is the determination of aldosterone excretion rate after salt loading. Patients in whom aldosterone excretion rates exceed 14.0 micrograms per 24 hours when the urinary sodium is at least 250 mEq per 24 hours are prime candidates for additional studies. The presence of hypokalemia and/or suppressed plasma renin activity provides corroborative evidence of primary aldosteronism, but the absence of either or both does not preclude the diagnosis. Spontaneous, moderately severe hypokalemia (less than 3.0 mEq per L), an anomalous postural decrease in plasma aldosterone concentration, and increased plasma 18-hydroxycorticosterone values (greater than 100 ng per dl) indicate the presence of an adenoma. For localization of an adenoma, an adrenal CT scan should be obtained first and is considered diagnostic if an adrenal mass is clearly identified. When the CT scan is inconclusive, adrenal venous sampling can be done for more definitive localization. In the presence of an adenoma, surgical excision is the recommended approach but only after pharmacologic normalization of arterial pressure and correction of metabolic abnormalities. Sustained salt and water depletion is the most important therapeutic goal for these patients, and cure can be achieved despite prolonged and severe hypertension.
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PMID:Primary aldosteronism. 306 43

A 46-year-old woman with hypertension, normokalemia, suppressed renin, normal catecholamines, and a left adrenal mass on the CT scan was found to have excessive 18-hydroxycorticosterone (18-OHB) and normal aldosterone levels in plasma, both of which responded poorly to sodium restriction and angiotension II, and supranormally to ACTH. Plasma 18-hydroxydeoxycorticosterone (18-OHDOC) was normal. After adrenalectomy, amelioration from hypertension occurred with a reduction in plasma 18-OHB and aldosterone. The plasma 18-OHDOC remained normal. The adrenal tumor was histologically an adenoma, containing a large amount of 18-OHB and a small amount of aldosterone. Thus, the present adenoma seems to be a variant of aldosteronomas.
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PMID:Adrenal adenoma with 18-hydroxycorticosterone excess and hypertension: a variant of aldosteronomas. 674 43

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)
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PMID:Incidentally discovered adrenal masses: a functional and morphological study. 822 80

1. Six (12%) out of 52 respondents to newspaper advertisements for antihypertensive drug trials had elevated aldosterone to renin ratio, confirmed by repeated measurement. 2. Failure to suppress aldosterone with fludrocortisone acetate administration and oral salt loading confirmed the presence of primary aldosteronism in all six patients. 3. Two of the six patients have already had aldosterone-producing adenomas removed, one has commenced spironolactone, and one has an adrenal mass on computerized tomography but investigation is incomplete. 4. None of the six patients with primary aldosteronism had unprovoked hypokalaemia. 5. Plasma aldosterone levels did not distinguish those patients with subsequently proven primary aldosteronism from the others. Plasma renin activity (PRA) was a better discriminator, but not as good as the aldosterone to renin ratio. 6. The incidence of primary aldosteronism is probably much higher than the 1% currently quoted in texts, with earlier, normokalaemic forms accounting for the majority of cases.
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PMID:Evidence that primary aldosteronism may not be uncommon: 12% incidence among antihypertensive drug trial volunteers. 832 12

The discovery of an asymptomatic adrenal mass (incidentaloma) during the investigation of an unrelated condition is relatively common. In this study, we report the clinical, radiologic, and endocrine evaluation of 38 patients (22 women and 16 men aged 24 to 84 years) with adrenal incidentaloma (size, 1 to 12 cm). The patients underwent basal and dynamic evaluation of the hypothalamic-pituitary-adrenal (HPA) axis, renin-angiotensin-aldosterone system, and adrenomedullary function. Moreover, computed tomograpy (CT) scan and 131I-6beta-iodomethyl-19-norcholest-5(10)-en-3beta-ol(NP-59) and/or 131I-metaiodobenzylguanidine (MIBG) scintigraphy were performed. The endocrine evaluation indicated two cases of pheochromocytoma and four cases of preclinical Cushing's syndrome, three of which underwent surgery with histologic diagnosis of two adrenocortical adenomas and one carcinoma. Low levels of serum dehydroepiandrosterone sulfate (DHEA-S), associated with a markedly increased 17-hydroxyprogesterone (17-OHP) response to a corticotropin (ACTH) test, were found in patients with incidentaloma. On the basis of endocrine and morphologic data, 13 patients underwent surgical treatment: five adrenocortical adenomas (two functioning), two pheochromocytomas, two ganglioneuromas, one cortisol-secreting adrenal carcinoma, one lymphangiomatous cyst, one myelolipoma, and one hemorrhage were found. Careful diagnostic assessment of incidentally discovered adrenal masses must be performed to exclude the presence of malignant and/or functioning lesions and to verify the possibility that patients with incidentaloma have a genetic or acquired deficit of adrenal steroidogenic activity.
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PMID:Evaluation of hormonal function in a series of incidentally discovered adrenal masses. 900 78

A 30-year-old man presented at our hospital with microscopic hematuria. Ultrasonography and computed tomography scanning revealed a right adrenal mass measuring 20 x 20 mm. The tumor was asymptomatic, but there was obvious accumulation on the right side when scintigraphy was performed with radioactive iodine (131I)-labeled adosterol. Endocrinology studies showed elevation of the plasma cortisol and renin concentrations, while the plasma aldosterone level was low. Right laparoscopic adrenalectomy was done on July 4, 1994. Histologic examination showed an adrenocortical adenoma. Serum levels of adrenocortical hormones were measured before and after surgery, and the tissue content for the same hormones was determined in the resected tumor. The hormonal studies showed that the tumor produced 18-hydroxycorticosterone.
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PMID:Adrenocortical adenoma producing 18-hydroxycorticosterone. 917 May 79

The basic clinical pathophysiology of primary aldosteronism (PAL) was described by Conn in terms of autonomous production of aldosterone, secondary suppression of renin and development of hypertension with hypokalaemic alkalosis. Conn recognised a normokalaemic form of the syndrome and suggested that it might masquerade as essential hypertension and be not uncommon. This was hotly disputed at the time, and normokalaemic PAL considered rare until recently, and, as a consequence, overlooked. The advent of a simple screening test, the aldosterone-renin ratio, led to recognition that normokalaemic forms are not uncommon. In fact, PAL may be the commonest specifically treatable and potentially curable form of hypertension so far identified. In all patients with PAL confirmed by lack of suppressibility ("autonomy") of aldosterone production, Familial Hyperaldosteronism Type I (FH-I, glucocorticoid-remediable hyperaldosteronism, reviewed elsewhere in this issue) should first be excluded by dexamethasone suppression or genetic testing. Capable of causing fatal stroke in young people affected by this dominantly inherited disorder, it can be reversed by doses of glucocorticoids such as dexamethasone which partially suppress endogenous ACTH without producing "steroid" side-effects. The remaining varieties of PAL may eventually also be shown to have a genetic basis, but are currently treated either by excision of a solitary aldosterone-secreting tumour or by antagonism of aldosterone's action in the renal tubule. It is possible that both adrenal cortices are genetically predisposed to overproduction of aldosterone in all varieties of PAL, whether because of anomalous regulation of aldosterone secretion or because of a tendency towards hyperplasia and neoplasia. Aldosterone-producing adenomas (APA's) can be divided into two main subtypes based on morphology and biochemical behaviour. The first subtype to be morphologically and biochemically characterised is composed predominantly of fasciculata-like cells and is unresponsive to angiotensin II (ALL-U-APA). The more recently characterised subtype is composed predominantly of glomerulosa-like cells, is responsive to angiotensin II (AII-R-APA) and could previously have been misdiagnosed as bilateral hyperplasia. The renin gene is often overexpressed in the second variety of adenoma, and in surrounding non-tumorous cortex, and the two subgroups show different allelic frequencies for RFLP's of the constitutive renin gene and the constitutive ANP gene locus. Unilateral, solitary, benign adrenal cortical adenomas producing aldosterone (APA's) represent a potentially surgically curable form of hypertension. Adrenal venous sampling (AVS) should always be performed because APA's are biochemically recognisable by adrenal venous steroid measurement before they are identifiable by computerised tomography or scintigraphy, and adrenal masses seen on CT may not be responsible for PAL. The secretory activity of adrenal masses must therefore be established by AVS before surgical removal. Discovery of an adrenal mass on CT requires formulation of a plan, whether or not it is found to be secreting hormones in excess. Independently of the treatment of the patient's hypertension, an apparently nonfunctioning adrenal mass ("incidentaloma") should be removed if 2.5 cm or more in diameter, because of the risk of cancer. Smaller masses require long-term follow-up. Primary aldosteronism not lateralising on AVS should be treated with low dose spironolactone, or with amiloride. For any such patients intolerant of medical treatment, laparoscopic removal of the adrenal showing higher production of aldosterone on AVS is an option worthy of consideration.The resultant reduction in mass of tissue autonomously secreting aldosterone should improve hypertension, as aldosterone productions falls below a critical level, and may even be curative in the short, medium or long term, depending on the rate of growth and activity of au
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PMID:Primary aldosteronism. 922 Dec 68


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