Alternative splicing of the human glucocorticoid receptor (hGR) pre-mRNA generates two highly homologous isoforms, termed hGRa and hGR. hGRa is a ligand-activated transcription factor which, in the hormone-bound state, modulates the expression of glucocorticoid-responsive genes by binding to specific glucocorticoid response element (GRE) DNA sequences. In contrast, hGRfi does not bind glucocorticoids and is transcriptionally inactive. We demonstrate here that hGR8 is able to inhibit the effects of hormone-activated hGRa on a glucocorticoid-responsive reporter gene in a concentration-dependent manner.['H]-Dexamethasone binding studies indicate that hGR*3 does not alter the affinity of hGRa for its hormonal ligand. The presence of hGR.8 in nuclear extracts and its ability to bind to a radiolabeled GRE oligonucleotide suggest that its inhibitory effect may be due to competition for GRE target sites.Reverse transcription-PCR analysis shows expression of hGRfi mRNA in multiple human tissues. These results indicate that hGRI3 may be a physiologically and pathophysiologically relevant endogenous inhibitor of glucocorticoid action, which may participate in defining the sensitivity of target tissues to glucocorticoids. They also underline the importance of distinguishing between the two receptor isoforms in all future studies of hGR function and the need to revisit old data. (J. Clin. Invest. 1995Invest. . 95:2435Invest. -2441

Mammals control the volume and osmolality of their body fluids from stimuli that arise from both the intracellular and extracellular fluid compartments. These stimuli are sensed by two kinds of receptors: osmoreceptor-Na+ receptors and volume or pressure receptors. This information is conveyed to specific areas of the central nervous system responsible for an integrated response, which depends on the integrity of the anteroventral region of the third ventricle, e.g., organum vasculosum of the lamina terminalis, median preoptic nucleus, and subfornical organ. The hypothalamo-neurohypophysial system plays a fundamental role in the maintenance of body fluid homeostasis by secreting vasopressin and oxytocin in response to osmotic and nonosmotic stimuli. Since the discovery of the atrial natriuretic peptide (ANP), a large number of publications have demonstrated that this peptide provides a potent defense mechanism against volume overload in mammals, including humans. ANP is mostly localized in the heart, but ANP and its receptor are also found in hypothalamic and brain stem areas involved in body fluid volume and blood pressure regulation. Blood volume expansion acts not only directly on the heart, by stretch of atrial myocytes to increase the release of ANP, but also on the brain ANPergic neurons through afferent inputs from baroreceptors. Angiotensin II also plays an important role in the regulation of body fluids, being a potent inducer of thirst and, in general, antagonizes the actions of ANP. This review emphasizes the role played by brain ANP and its interaction with neurohypophysial hormones in the control of body fluid homeostasis.

Mutations in the neurokinin B pathway are relatively common as causes of hypogonadism. Although the neurokinin B pathway appears essential during early sexual development, its importance in sustaining the integrity of the hypothalamic-pituitary-gonadal axis appears attenuated over time.

Screening tests have been used to support a biochemical diagnosis of Cushing's syndrome (CS). Measurements of salivary cortisol offer facilities for studying out-patients. This study assessed salivary cortisol in screening for CS by evaluating hypercortisolism based on circadian rhythm and the overnight 1-mg dexamethasone (DEX) suppression test for out-patients. We evaluated 33 patients with CS. Thirty normal volunteers and 18 obese patients were used as controls. Salivary cortisol (nanograms per dL) levels (mean +/- SEM) were 596 +/- 44, 528 +/- 104, and 1205 +/- 118 (0900 h); 213 +/- 27, 325 +/- 76, and 778 +/- 74 (1700 h); and 95 +/- 8, 133 +/- 26, and 914 +/- 94 (2300 h) in normal controls, obese subjects, and CS patients, respectively. After the overnight 1-mg DEX test, they were 64 +/- 1.1, 107 +/- 25, and 1048 +/- 129, respectively. In the present series, a single out-patient 0900, 1700, and 2300 h measurement and an overnight 1-mg DEX salivary cortisol level above the 90th percentile of the control or obese group values had sensitivities of 65.6%, 81.8%, 100%, and 100% or 78.1%, 57.6%, 93.3%, and 91.4%, respectively. The sensitivity improved (100%) in response to the combination of 2300 h and overnight 1-mg DEX salivary cortisol suppression tests to differentiate between obese and CS subjects. Our data indicate that nighttime sample and overnight 1-mg DEX suppression salivary cortisol tests are sensitive markers for the diagnosis of CS. In addition, the combination of the two tests improves the ability to differentiate between obese and CS patients and may be useful for out-patient screening.

Background: Alternative splicing of the transcripts of the human glucocorticoid receptor gene results in two mutually exclusive products, the dassic, ligand-binding glucocorticoid receptor (hGRa), and a dominant negative non-ligand-binding isoform, hGR(3. Materials and Methods: We examined the existence of and quantified both hGRa and hGR,B isoforms in a panel of human tissues, as well as in intact and fractionated HeLa cells, using specific quantitative Western blots and/or immunocytochemistry. We studied the potential interactions of hGR,B with heat shock protein (hsp) 90 and/or hGRa using crossimmunoadsorption/precipitation procedures followed by Western blots. Results: For the first time, we demonstrated the natural existence of the hGRI3 protein, which was widely expressed in human tissues. The ratio of immunoreactive hGRa to hGR(3 varied from 0.2 to 1.0 among different tissues, and was approximately 0.2 in HeLa cells. In the latter, both isoforms were distributed in the cytoplasm and nucleus in the absence of the hormonal ligand, and translocated into the nucleus after addition of dexamethasone. The cytosolic and nudear hGRa-to-hGR/3 ratio remained the same before and after dexamethasone exposure, suggesting that upon activation the two isoforms translocated into the nucleus in equal proportions. hGRa-and hGR(3-specific antibodies cross-adsorbed and precipitated cytosolic and nuclear glucocorticoid hGRa and hGR,B, respectively, as well as hsp9o, suggesting that hGRa and hGRP are in complex with hsp9O and/or each other. Conclusions: The hGRi3 protein is widely expressed throughout the human body and present mostly in the cytoplasm of human cells, in complex with hsp9o and other proteins. In the presence of glucocorticoid, hGR/3 probably heterodimerizes with ligand-bound hGRa and translocates into the nudeus to act as a dominant negative inhibitor of the classic receptor.

We have identified novel inherited MKRN3 defects in children with apparently sporadic CPP, supporting a fundamental role of this peptide in the suppression of the reproductive axis.

We identified novel mutations in KAL1 and FGFR1 genes in IHH patients. FGFR1 mutations were identified in 17% of the patients with olfactory abnormalities and in one of 34 normosmic IHH patients. In addition, isolated anosmia was identified in two unrelated females as a partial phenotypic manifestation of FGFR1 defects.

These data indicate that central nitric oxide arising from the inducible nitric oxide synthase pathway plays an important inhibitory role in vasopressin release during experimental septic shock and may be responsible for the hypotension occurring in this vasodilatory shock.