ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Studies using biochemical and pharmacologic approaches in steroidogenic cells and subcellular fractions have shown that the peripheral-type benzodiazepine receptor (PBR) is an outer mitochondrial membrane protein involved in the regulation of cholesterol transport from the outer to the inner mitochondrial membrane, the rate-determining step in steroid biosynthesis. Recent studies using gene targeting, antisense RNA, gene expression, and mutagenesis technology have demonstrated the obligatory role of PBR in cholesterol transport. In addition, the development ofin vivomodels and ontogeny studies have validated data obtained inin vitroexperiments, confirming the role of PBR in steroidogenesis and suggesting that the presence of PBR is an absolute prerequisite for adrenocortical function.

ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

DAX-1 is an unusual member of the nuclear hormone receptor superfamily. Its mutations cause adrenal hypoplasia congenita, a disease of the adrenal cortex that is characterized by an impairment of the genesis of the permanent zone. Here we present an overview of the pathologic and clinical features of adrenal hypoplasia congenita and describe some recent advances in the understanding of the biologic role of DAX-1.

ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Intracellular interconversion of active 11-hydroxy glucocorticoids (cortisol, corticosterone) and inert 11 keto products (cortisone, 11-dehydrocorticosterone) by 11β-hydroxysteroid dehydrogenase (11β-HSD) enzymes has emerged as a new, potent mechanism of regulation of glucocorticoid action. 11β-hydroxysteroid dehydrogenase type 1 is a widespread, NADP(H)-dependent enzyme that shows bidirectional activity in tissue homogenates and microsomal preparations but functions predominantly as an 11β-reductase (regenerating active glucocorticoids) in intact cells. 11β-hydroxysteroid dehydrogenase type 2 is a much higher-affinity, NAD-dependent, exclusive 11β-dehydrogenase (glucocorticoid inactivating) enzyme that protects mineralocorticoid receptors in distal nephrons from nonselective activation by glucocorticoidsin vivo. This review discusses the physiologic functions of 11β-HSDs and their potential diagnostic and therapeutic implications, as revealed by comparison of specific inhibition of 11β-HSD activity by pharmacologic substances and by genetic mutations (spontaneous in humans; targeted in mice).

ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Laparoscopic adrenalectomy is one of the most significant advances made in the past 20 years for the treatment of adrenal disorders. This minimally invasive approach to the adrenal gland has proven to be a useful technique for most nonmalignant adrenal disorders that require surgery. The key features of the lateral transabdominal laparoscopic approach are the insertion of trocars, the use of pneumoperitoneum, and tissue manipulation using video monitoring. Laparoscopic adrenalectomy is safe, effective, and curative; shortens hospitalization and convalescence; and produces less long-term morbidity than open adrenalectomy. The laparoscopic approach to the adrenal gland is the procedure of choice for the surgical management of aldosterone-producing adenomas, cortisol-producing adenomas, apparent nonfunctioning adrenal masses that require intervention, and pheochromocytomas, and for patients with adrenocorticotropin-dependent Cushing’s syndrome in whom surgery to remove the source of adrenocorticotropic hormone has failed. The keys to successful laparoscopic adrenalectomy are appropriate patient selection, knowledge of anatomy, delicate tissue handling, meticulous hemostasis, and experience with the technique.

ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

In the past 10 years, the two dogmas that serve as classic definitions of aldosterone—a synthesis in the adrenal glands only and an action exclusively in epithelial tissues—have been challenged. The presence of specific aldosterone receptors and of the enzyme 11β—hydroxysteroid dehydrogenase II, which confers mineralocorticoid specificity on aldosterone-responsive cells in the heart, has considerably broadened our understanding of aldosterone’s possibilities of action. This suggests that cardiac tissue may be a genuine target for aldosterone. Indeed, the effects of aldosterone on several aspects of cardiac function have been described. The recent discovery of a system of aldosterone biosynthesis in the heart has made local autocrine or paracrine action a possibility. These observations indicate that locally produced aldosterone may have a role independent of that of plasma hormones.

ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Adrenocortical function undergoes diverse changes throughout development and aging and, in many instances, the pattern of production of some adrenal steroids differs from the responses of other adrenal steroids to the same physiologic and pathophysiologic circumstances. The diversity of responses of the various portions of the steroidogenic pathway in the adrenal results from the morphologic and functional zonation of the adrenal cortex. For the most part, however, the mechanisms responsible for establishing adrenocortical zonation and maintaining the biosynthetic and morphologic integrity of the different adrenocortical cell types have yet to be determined. Both subtle and dramatic alterations in adrenal function have been documented in aging and in other circumstances, and evidence suggests that such changes in adrenal steroidogenesis adversely affect other physiologic systems. This review addresses the general topic of adrenal function during aging and summarizes the results of recent studies that have contributed to our greater understanding of the relationship between aging and adrenal function.

ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Male sex and menopause are independent risk factors for cardiovascular disease. Estrogens bind to vascular receptors, including the novel estrogen receptor-β and membrane-bound receptors, and they contribute to vascular resistance through several mechanisms. Estrogens modulate gene expression, membrane potentials, and expression of receptors; modify activity of vasoactive peptides and vascular enzymes; and act as antioxidants, favoring a state of vasodilatation and inhibiting vascular growth. Accordingly, estrogens have been shown to improve vascular function in animals and humans and to inhibit the response to injury after balloon angioplasty and the progression of atherosclerosis. New mechanisms of estrogen action, the role of estrogen receptor-β in the vasculature, and recent evidence for synthetic progestogens as potential antagonists of vascular estrogen actions are discussed.

ISSN:1068-3097    

出版商:OVID    

年代:1999

数据来源: OVID