Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Somatostatin receptors in the rat pituitary gland were characterized by binding analysis with a radioiodinated high affinity somatostatin analogue, 125I-Tyr1[D-Trp8]somatostatin. Receptor binding of this derivative reached equilibrium at 30 min and was maintained at a plateau for at least 60 min. Two L-Trp8- labeled somatostatin analogues. 125I-Tyr1- and [125I-Tyr11]somatostatin, displayed less stable and lower specific uptake and higher nonspecific binding. In contrast to the rapid degradation of the L-Trp8 ligands during binding assay, 125I-Tyr1]D-Trp8]somatostatin retained more than 80% of its binding activity after 90 min of incubation with pituitary particles. Pituitary particles bound 125I-Tyr1]D-Tyr8]somatostatin with high affinity (Ka = 8.6 +/- 1.2 X 10(9) M-1) and capacity of 54.4 +/- 2.6 fmol/mg. These binding sites showed specificity for the native peptide and its active analogues, and other peptide hormones, including angiotensin II, thyrotropin-releasing hormone, vasopressin, oxytocin, substance P, and gonadotropin-releasing hormone, did not inhibit tracer binding. A good correlation was observed between the binding affinities of several somatostatin analogues and their potencies as inhibitors of growth hormone release in rat pituitary cells. These findings emphasize the physiological importance of the pituitary somatostatin receptor in mediating the inhibitory action of the peptide on growth hormone release. The use of Tyr1[d-Trp8]somatostatin as a labeled ligand permits accurate determinations of the binding affinity and concentration of receptors for somatostatin in the normal pituitary gland and provides a basis for further studies of somatostatin receptor regulation and receptor-mediated cellular effects of the tetradecapeptide.
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PMID:Pituitary somatostatin receptors. Characterization by binding with a nondegradable peptide analogue. 612 Jan 62

Pituitary adenomas were obtained from eight of nine patients with Cushing's disease, and the surrounding tissues as well were obtained from six of nine patients. ACTH, beta-lipotropin (beta-LPH), beta-endorphin, GH, TSH, LH, and PRL concentrations in these tissues were determined by RIA. Immunoreactive ACTH and beta-endorphin (beta-endorphin + beta-LPH) were present in high concentrations in all adenomas, and low concentrations were found in the surrounding tissues, except for one patient. As compared to levels seen in normal pituitary tissue, the GH concentration in the surrounding tissues was suppressed in five of six cases. TSH and LH concentrations were suppressed in four and three cases, respectively. The PRL concentration was not suppressed in any of the six patients studied. These four hormones were not detected in any adenoma. Plasma GH, TSH, and LH responses to various stimuli which were suppressed preoperatively returned to normal in most of the patients after adenomectomy. Basal plasma cortisol concentrations were normal or subnormal and were suppressed by the administration of 1 mg dexamethasone after adenomectomy, in contrast to the lack of such suppression preoperatively. ACTH and beta-endorphin secretion were stimulated by lysine-8-vasopressin and suppressed by dexamethasone and cyproheptadine in vitro.
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PMID:Anterior pituitary hormones in plasma and pituitaries from patients with Cushing's disease. 625 28

Pituitary microadenomas may present with subtle or no mass effect. They may appear lucent, dense, or heterogeneous on computed tomographic (CT) images. The normal pituitary gland may also have a nonhomogeneous CT appearance with intermingled lucent and dense areas. This heterogeneity is related in part to microscopic variation within the anterior and posterior lobes. Thirteen autopsy specimens of the pituitary gland were examined by coronal CT and histologically sectioned in similar coronal planes. The CT-lucent and CT-dense areas of the anterior and posterior lobes were correlated with corresponding areas on microscopic examination. To determine the effects of contrast infusion during CT, density measurements of lucent and dense areas in the anterior lobes of 26 normal contrast-enhanced pituitary glands in vivo were compared with density measurements of adjacent vascular structures at the time of scanning. Microscopic features corresponding to increased CT density in the anterior lobe included increased tissue compactness and increased cellular granularity, both of which usually occurred together in areas composed of tightly compacted and heavily granulated acidophilic cells. Conversely, microscopic features corresponding to decreased CT density in the anterior lobe included decreased tissue compactness and decreased cellular granularity, both of which frequently occurred together in areas containing chromophobic and/or mildly to moderately granulated basophilic cells. The degree of contrast enhancement within the anterior lobe appeared primarily to depend on vascularity, which in turn often depended on the degree of tissue compactness. In the posterior lobe, CT-lucent areas appeared to correspond to less compact and/or less vascular neurohypophyseal tissue.
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PMID:Normal pituitary gland: 2. Microscopic anatomy-CT correlation. 641 Aug 78

A correlative radioimmunoassay (RIA) and immunocytochemical (ICC) study was carried out on vasopressin (VP) distribution and content in brains of normal and 3-day water-deprived rats. By RIA there were statistically significant differences in brain VP per pg/mg between normal and osmotically stressed specimens in hypothalamus (338.4 versus 134.4), thalamus (4.8 versus 0.9), septum (18.0 versus 3.4), striatum (1.6 versus 0.7) and amygdala (17.3 versus 1.3), but not in other brain regions measured. Pituitary VP decreased from 71.1 to 8.7 ng/mg, and plasma VP rose from 3.6 to 19.3 pg/ml during water deprivation. Application of the peroxidase-anti-peroxidase ICC method of Sternberger to vibratome sections showed that VP-immunoreactivity in dehydrated specimens decreased in perikarya of paraventricular nucleus and suprachiasmatic nucleus, while intrahypothalamic immunoreactive magnocellular fibers appeared more conspicuous due to proliferation of large Herring bodies. In extrahypothalamic sites VP-immunoreactivity in water-deprived rats was visibly reduced in periventricular thalamus and septum. Thus it is apparent that both intra- and extrahypothalamic VP are affected by osmotic stress, and these results are discussed within the context of current ideas relating to co-activation of neurosecretory cells that project to different sites.
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PMID:Changes in hypothalamic and extra-hypothalamic vasopressin content of water-deprived rats. 661 68

We have previously shown that female rats exposed to an alcohol (ethanol, E) diet exhibited a blunted ACTH response to systemically administered interleukin-1 beta (IL-1 beta). Because of the presence of gender differences in the activity of the hypothalamic-pituitary-adrenal (HPA) axis, and of the possible role played by sex steroids in modulating the inhibitory influence of E in females, we studied the ability of a 10-day E diet to alter ACTH and corticosterone secretion of intact or castrated male rats injected with IL-1 beta or endotoxin, a releaser of endogenous cytokines. Pituitary responsiveness to secretagogues that mediate the endocrine effects of IL-1 beta, namely corticotropin-releasing factor (CRF) and vasopressin (VP), was also investigated. The ACTH responses of animals fed ad libitum (C group) or pair-fed (PF group) to the intravenous administration of IL-1 beta or endotoxin were not statistically different (p > 0.05); therefore, results from these two groups were combined in the initial experiments. Subsequent experiments only used E and C animals. When compared with this latter group, intact E males showed a significant (p < 0.01) decrease in ACTH levels measured 30 and 60 min after the intravenous injection of IL-1 beta or endotoxin. In contrast, E rats released as much corticosterone as C rats in response to IL-1 beta, but significantly (p < 0.05) more following administration of endotoxin (lipopolysaccharide). The stimulatory effect of VP on ACTH release was also measurably blunted by alcohol, whereas that of CRF was not. In none of these experiments were any significant differences observed between C and PF rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Altered ACTH and corticosterone responses to interleukin-1 beta in male rats exposed to an alcohol diet: possible role of vasopressin and testosterone. 777 51

Cushing's syndrome occurs rarely; in analyzing 50 cases studied at our institution we discuss the following aspects: syndromatic diagnosis, etiologic differentiation into the 3 categories of the syndrome, and therapeutic strategies for each variety. We postulate that non-endocrinologists should be responsible for the syndromatic diagnosis, easily done by using 2 simple tools: the measurement of basal free urinary cortisol and the performance of an overnight suppression of the adrenal axis with 1 mg of dexamethasone (Nugent's test). In contrast, the etiologic diagnosis and the therapeutic interventions should be strictly restricted to highly specialized institutions having well seasoned endocrinologists, a reliable endocrine laboratory, easy access to computed tomographies of the brain and abdomen as well as to nuclear resonance imaging of the brain. The usefulness of our in-house devised vasopressin challenge following overnight dexamethasone suppression for the etiologic diagnosis is highlighted. Neurosurgical expertise in the transsphenoidal approach to the pituitary gland as well surgeons well experienced in adrenal surgery are a must to offer a reasonable chance of success to patients with the syndrome. Forty one (82%) of the series were female patients, 78% were pituitary-dependent and 22% pituitary-independent Cushings. Six out of 8 (75%) of the adrenal tumors were carcinomas. Only 3 patients (6%) qualified as ectopic ACTH syndromes. The easiest variety to diagnose and treat was the adrenal adenoma (2 cases); adrenal carcinomas were always incurable. The ectopic ACTH syndrome was amenable to successful medical treatment with ketoconazole or surgical resolution with complete resection of the offending tumor (1 of 3 cases) or bilateral adrenalectomy (2 of 3 cases) Pituitary-dependent Cushings are quite tricky to diagnose and difficult to treat. Transsphenoidal resection of the offending microadenoma was successful in only 43.5% (10/23) of cases and we experienced 3 recurrences of the syndrome even after 8 years of successful removal of the pituitary adenoma. The remainder had to be cured by bilateral adrenalectomy. Seven out of 39 patients with Cushing's disease (18%) ultimately died for a variety of reasons; six out of 6 patients (100%) with adrenal carcinoma died of dissemination; two out of 2 adrenal adenomas cured and 1 out of the 3 ectopic ACTH syndromes died of dissemination of a malignant thymic carcinoma. We conclude that Cushing's syndrome is a serious, underdiagnosed disorder, which should be suspected and diagnosed by the non specialized physician and then referred to a specialized center for expert etiologic diagnosis and surgical therapy.
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PMID:[Cushing's syndrome: review of a national caseload]. 852 77

Surgical pituitary stalk compression (PSC) causes neural lobe denervation and development of ectopic magnocellular terminals in the external zone of the median eminence, resulting in shunting of magnocellular vasopressin (VP) and oxytocin (OT) to the pituitary portal circulation. To determine the effects of PSC on hypothalamic and pituitary function, VP and CRH receptors and POMC messenger RNA (mRNA) in the pituitary, and CRH, VP, and OT mRNA levels in the PVN were examined in 7-day PSC and sham-operated rats. Immunohistochemical staining revealed marked accumulation of immunoreactive VP in the swollen pituitary stalk and the external zone of the distal median eminence of PSC rats. Plasma ACTH and corticosterone levels were significantly increased by PSC, an effect that was attenuated by minipump infusion of desamino-[D-Arg8]-vasopressin (DDAVP) given to correct the diabetes insipidus. [3H]VP binding to anterior pituitary membranes from PSC rats was reduced by 50% compared to that in sham-operated controls, but VP V1b receptor mRNA levels measured by in situ hybridization were unchanged. Pituitary CRH receptors measured by binding autoradiography and CRH receptor mRNA levels did not change after PSC. POMC mRNA was unchanged in the anterior pituitary lobe, but markedly increased in the intermediate lobe of PSC rats, with or without DDAVP infusion. In the hypothalamic supraoptic and paraventricular nuclei, PSC resulted in reduction of VP mRNA (-83%) and OT mRNA (-38%) levels, probably reflecting retrograde degeneration of magnocellular neurons. This decrease was more pronounced for VP mRNA than for OT mRNA CRH mRNA levels in parvicellular cells of the paraventricular nuclei of PSC rats were reduced by 55%. Correction of the diabetes insipidus by DDAVP treatment further decreased hypothalamic VP mRNA levels, but restored CRH mRNA to control levels. The data show that continuous exposure of the pituitary to high VP levels from ectopic magnocellular fibers in the median eminence results in VP, but not CRH, receptor loss. Pituitary VP receptor down-regulation and decreased hypothalamic CRH expression are likely to contribute to the reduced corticotroph responsiveness to VP reported in this experimental model.
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PMID:Hypothalamic-pituitary corticotroph function after shunting of magnocellular vasopressin and oxytocin to the hypophyseal portal circulation. 859 5

Pituitary function was assessed in healthy adult beagle dogs before and after hypophysectomy. Anterior pituitary function was tested by use of the combined anterior pituitary (CAP) function test, which consisted of sequential 30-sec intravenous injections of four hypothalamic releasing hormones, in the following order and doses: 1 microgram of corticotropin-releasing hormone (CRH)/kg, 1 microgram of growth hormone-releasing hormone (GHRH)/kg, 10 micrograms of gonadotropin-releasing hormone (GnRH)/kg, and 10 micrograms of thyrotropin-releasing hormone (TRH)/kg. Plasma samples were assayed for adrenocorticotropin (ACTH), cortisol, GH, luteinizing hormone (LH), and prolactin (PRL) at multiple times for 120 min after injection. Pars intermedia function was assessed by the alpha-melanotropin (alpha-MSH) response to the intravenous injection of the dopamine antagonist haloperidol in a dosage of 0.2 mg/kg. Posterior pituitary function was assessed by the plasma vasopressin (AVP) response to the intravenous infusion of 20% saline. Basal plasma ACTH, cortisol, thyroxine, LH. PRL, and AVP concentrations were significantly lower at 10 wk after hypophysectomy than before hypophysectomy. In the CAP test and the haloperidol test, the peaks for the plasma concentrations of ACTH, cortisol, GH, LH, PRL, and alpha-MSH occurred within 45 min after injection. At 2 and 10 wk after hypophysectomy, there were no responses of plasma GH, LH, PRL, and alpha-MSH to stimulation. In four of eight hypophysectomized dogs, there were also no plasma ACTH and cortisol responses, whereas in the other four dogs, plasma ACTH and cortisol responses were significantly attenuated. The basal plasma ACTH and cortisol concentrations were significantly lower in the corticotropic nonresponders than in the responders. Plasma AVP responses were completely abolished by hypophysectomy, although water intake by the dogs was normal. Histopathological examinations at 10 wk after hypophysectomy revealed that adrenocortical atrophy was much more pronounced in the corticotropic nonresponders than in the responders. No residual pituitary tissue was found along the ventral hypothalamic diencephalon. However, in all hypophysectomized dogs that were investigated, islets of pituitary cells were found embedded in fibrous tissue in the sella turcica. A significant positive correlation was found between the number of ACTH-immunopositive cells and the ACTH increment in the CAP test at 10 wk after hypophysectomy. It is concluded that 1) stimulation of the anterior pituitary with multiple hypophysiotropic hormones, stimulation of the pars intermedia with a dopamine antagonist, and stimulation of the neurohypophysis with hypertonic saline do not cause side effects that would prohibit routine use, 2) in the routine stimulation of the anterior pituitary and the pars intermedia, blood sampling can be confined to the first 45 min, 3) the ACTH and cortisol responses to hypophysiotropic stimulation are the most sensitive indicators for residual pituitary function after hypophysectomy, 4) small islets of pituitary cells in the sella turcica, containing corticotropic cells, are the most likely source of the attenuated corticotropic response that may occur after hypophysectomy, and 5) residual AVP release from the hypothalamus after hypophysectomy is sufficient to prevent diabetes insipidus, despite the fact that the AVP response to hypertonic saline infusion is completely abolished.
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PMID:Assessment of pituitary function after transsphenoidal hypophysectomy in beagle dogs. 906 51

Pituitary corticotropic cells express a specific vasopressin receptor, called V1b or V3, through which vasopressin stimulates corticotropin secretion. We recently cloned a cDNA coding for this receptor and showed that it belongs to the G protein-coupled receptor family. V3 mRNA is readily detected by RT-PCR in normal human pituitaries and corticotropic pituitary adenomas but not in PRL or GH-secreting adenomas, thus demonstrating that, like POMC itself and the CRH receptor, V3 is a marker of the corticotropic phenotype. Nuclease protection experiments suggest that V3 is overexpressed in some corticotropic adenomas, and thus may play a role in tumor development by activating the phospholipase C-signalling pathway. In addition analysis of its expression in nonpituitary neuroendocrine tumors showed a striking association with carcinoids of the lung responsible for the ectopic ACTH syndrome.
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PMID:V3 vasopressin receptor and corticotropic phenotype in pituitary and nonpituitary tumors. 916 61

The majority of cases of central diabetes insipidus are still pathogenetically unclear (idiopathic). Atherosclerotic cholesterol emboli might be partly responsible for some of these idiopathic cases. A 54-year-old woman with known aortic valve stenosis and a history of a transitory ischemic attack presented with sudden-onset polyuria and polydipsia of up to eight l/d, which had started acutely with headaches. She had been treated with lithium for 3 years because of cyclothymic depression. Plasma sodium was in the upper normal range (142-148 mmol/l). Hypertonic saline infusion during lithium therapy revealed a normal threshold of thirst and resetting of vasopressin secretion (osmotic threshold > 300 mosmol/l), whereas vasopressin reserve was normal. Lithium withdrawal led to an even greater delay of vasopressin release upon hypertonic saline infusion (> 310 mosmol/l). Pituitary function tests revealed a normal anterior pituitary function. MR imaging of the hypothalamo-hypophyseal region showed a normal hypothalamic region and a highly intensive neurohypophyseal signal in the T1-weighted image. The patient responded well to desmopressin. We suggest that in this rare case clinical symptoms as well as biochemical findings like impairment of AVP release might be related to a minor structural hypothalamic damage by a vascular lesion, caused, for example, by an atheromatous (cholesterol) embolism in the hypothalamic region responsible for integration of osmoreceptor function and AVP-secretion. The patient's atherosclerosis and aortic stenosis might be responsible for this event.
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PMID:Atherosclerosis, aortic stenosis and sudden onset central diabetes insipidus. 928 11


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