Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ligand specificity of rat adenohypophyseal vasopressin receptors was directly compared to that of peripheral receptors of the V1 and V2 types. For this purpose a series of 15 recently designed vasopressin antagonists was used. The affinities of these antagonists for rat adenohypophyseal membranes were deduced from the determination of the concentration-dependent inhibition of [3H]vasopressin binding. In parallel experiments the corticotropin (or anti-corticotropin)-releasing activities of the tested peptides were determined on freshly dispersed rat adenohypophyseal cells. All peptides tested which were found to be antagonists of the vasopressor and antidiuretic responses to vasopressin in vivo behaved as antagonists of vasopressin-induced corticotropin release. There was a close correlation between the relative affinities of the analogues tested for binding to adenohypophyseal membranes and their relative potencies in inhibiting vasopressin-induced corticotropin release, indicating that the detected vasopressin-binding sites are the receptors involved in the vasopressin effect on corticotropin secretion. No correlation could be demonstrated between anti-corticotropin-releasing activities and either anti-antidiuretic or antivasopressor potencies of the antagonists tested. A direct comparison of the ligand specificities of adenohypophyseal receptors on the one hand, and V1 (hepatic) and V2 (renal) receptors on the other hand, showed that most of the antagonists discriminated very efficiently between adenohypophyseal and either hepatic or renal receptors. The selectivity index reaches values as high as 260,000 for desGly(NH2)9 [1-(beta-mercapto-beta, beta-cyclopentamethylenepropionic acid), 2-D-O-ethyl-tyrosine, 4-valine] arginine vasopressin. It is concluded that adenohypophyseal receptors represent a novel type of vasopressin receptors. Based on the observation that adenohypophyseal receptors, like hepatic or vascular V1 receptors, do not appear to be coupled to adenylate cyclase, we propose that adenohypophyseal receptors could be designated as V1b receptors as opposed to the V1a receptors previously characterized on liver and blood vessels.
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PMID:Vasopressin antagonists allow demonstration of a novel type of vasopressin receptor in the rat adenohypophysis. 301

Studies of whole body balances of non-metabolizable base (NB) and several electrolytes and of the acid-base status of blood and urine during development of corticotropin-induced alkalosis in the weanling rat were carried out in order to identify the primary source of base and factors instrumental in maintenance of the alkalotic state. The data were compared to baseline and running control values and to the results of whole carcass analysers. Primary accumulation of NB was accounted for by ongoing gastrointestinal NB absorption in the weight-losing animal, distributed to extracellular and non-extracellular compartments of the body. An increase in the rate of renal excretion of non-metabolizable acid (NA), from negative values to zero, corresponded to an increased load of endogenous sulphuric acid and a reduced rate of gastrointestinal NB absorption. Accordingly, the renal response did not per se contribute to the induction of extracellular alkalosis. Maintenance of alkalosis occurred in spite of ample chloride in the renal tubular lumen and a moderate increase in relative extracellular volume. In the absence of evidence of overloading (with base) or malfunction of the kidney, corticotropin-induced alkalosis is classifiable as a 'set-point disturbance' of acid-base metabolism in which fluctuations in the (non-renal) load of NA lead to commensurate changes in renal NA excretion at an elevated extracellular pH. Withdrawal of corticotropin injections was followed by prompt restoration of a normal extracellular acid-base status and a return to reference values for renal NA excretion despite a marked fall in the balance of NB. This observation supports a concept of the extracellular compartment as the immediate reference system of the kidney.
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PMID:Corticotropin-induced alkalosis in the weanling rat and its relation to the balance of non-metabolizable base. 631 53

We hypothesized that in nonectopic Cushing syndrome there is an insufficient activity of type II (renal) 11beta-hydroxysteroid dehydrogenase (11beta-HSD2) that is related to cortisol excess, rather than to corticotropin (adrenocorticotropic hormone [ACTH]) levels. We measured plasma ACTH and urinary-free cortisol (UFF), urinary-free cortisone (UFE), tetrahydrocortisol (UTHF), and tetrahydrocortisone (UTHE) in 24-h urine samples of 24 healthy subjects and 15 patients diagnosed with nonectopic Cushing syndrome. Then, in the group of patients, a new 24-h urine sample was collected after treatment with 800 mg daily of ketoconazole. The UFF/UFE and UTHF/UTHE ratios were calculated as an estimation of 11beta-HSD2 activity. The patients had an increase in both the UFF/UFE (19.95 +/- 10.3 vs 5.78 +/- 4.72 nmol/24 h; p < 0.0001) and UTHF/UTHE ratios (5.36 +/- 5.23 vs 1.39 +/- 0.95 nmol/24 h; p < 0.001). Both UFF/UFE and UTHF/UTHE ratios decreased after ketoconazole treatment (19.95 +/- 10.3 vs 12.2 +/- 6.9 nmol/24 h; p < 0.005; and 5.36 +/- 5.23 vs 1.62 vs 1.21 nmol/24 h; p < 0.001, respectively). The control subjects had a significant relationship between UFF and UFE (r = 0.70, p < 0.0001), and between UTHF and UTHE (r = 0.75, p < 0.0001) that did not exist in the patient group. After ketoconazole treatment, the decrease in cortisol excretion in the patient group allowed a positive and significant relation between UFF and UFE (r = 0.64, p < 0.01) and between UTHF and UTHE (r = 0.56, p < 0.05) to appear. There was not any significant relationship between either UFF/UFE or UTHF/UTHE ratios and plasma levels of ACTH.
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PMID:Role of ketoconazole treatment in urinary-free cortisol-to-cortisone and tetrahydrocortisol-to-tetrahydrocortisone ratios in nonectopic Cushing's syndrome. 1245 Mar 20