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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The adrenal responses to insulin-induced hypoglycemia and the rapid adrenocorticotropic hormone (ACTH) stimulation test were compared in 24 healthy volunteers, 18 of whom also underwent a rapid oral metyrapone test. The cortisol levels after hypoglycemia (18.0-30.0 microgram/100 ml) were similar to and directly related to the levels after ACTH (21.0-31.0 microgram/100 ml). The levels after both stimuli were independent of age, sex, height, and weight. The 11-deoxycortisol response to the metyrapone test was less than the cortisol response to hypoglycemia and metyrapone administration was associated with more unpleasant side effects. In a group of 69 control subjects, the post-ACTH cortisol levels were 15.0 to 80.0 microgram/100 ml while in seven patients with Addison's disease they were less than 1-4.5 microgram/100 ml. In 44 control subjects, the posthypoglycemia cortisol levels were 18.0 to 30.0 microgram/100 ml compared with less than 1.0-9.0 microgram/100 ml in 22 patients with hypopituitarism. The absolute poststimulation cortisol levels provided better separation of control subjects from patients with adrenal or pituitary insufficiency than either the increment in cortisol levels or the 11-deoxycortisol response to metyrapone.
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PMID:A comparison of the adrenal responses to hypoglycemia, metyrapone and ACTH. 20 17

GH4C1 cells are a clonal strain of rat pituitary tumor cells which synthesize and secrete prolactin and growth hormone. Somatostatin, a hypothalamic tetradecapeptide, inhibits the release of growth hormone and, under certain circumstances, also prolactin from normal pituitary cells. We have prepared [125I-Tyr1]somatostatin (approximately 2200 C1/mmol) and have shown that this ligand binds to a limited number of high affinity sites on GH4C1 cells. Half-maximal binding of somatostatin occurred at a concentration of 6 x 10(-10) M. A maximum of 0.11 pmol of [125I-Tyr1]somatostatin was bound per mg of cell protein, equivalent to 13,000 receptor sites per cell. The rate constant for binding (kon) was 8 x 10(7) M(-1) min(-1). The rate constant for dissociation (koff) was determined by direct measurement to be 0.02 min(-1) both in the presence and absence of excess nonradioactive somatostatin. Binding of [125I-Tyr1]somatostatin was not inhibited by 10(-7) M thyrotropin-releasing hormones. Substance P, neurotensin, luteinizing hormone-releasing hormone, calcitonin, adrenocorticotropin, or insulin. Of seven nonpituitary cell lines tested, none had specific receptors for somatostatin. Somatostatin was shown to inhibit prolactin and growth hormone production by CH4C1 cells. The dose-response characteristics for binding and the biological actions of somatostatin were essentially coincident. Furthermore, among several clonal pituitary cell strains tested, only those which had receptors for somatostatin showed a biological response to the hormone. We conclude that the characterized somatostatin receptor is necessary for the biological actions of somatostatin on GH4C1 cells.
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PMID:Characterization of functional receptors for somatostatin in rat pituitary cells in culture. 21 Jan 85

1. Adipocytes isolated from rats 6--9 days after adrenalectomy had significantly increased sensitivity to insulin action against noradrenaline-stimulated lipolysis. In the presence of adenosine deaminase there was no significant difference in insulin sensitivity between cells from adrenalectomized and sham-operated rats. 2. Adipocytes from adrenalectomized rats had decreased lipolytic responses to all concentrations of noradrenaline and glucagon tested and a decreased lipolytic response to low but not high concentrations of corticotropin. There was no difference in lipolytic response to theophylline after adrenalectomy. Adenosine deaminase corrected the differences in response to noradrenaline and glucagon resulting from adrenalectomy. 3. In the presence of adenosine deaminase rates of lipolysis, after stimulation by high concentrations of noradrenaline, glucagon, corticotropin or theophylline, were the same in cells from adrenalectomized or sham-operated rats. 4. These findings and previously reported effects of adenosine and adrenalectomy on adipocyte function are discussed. It is proposed that changes in adipocyte hormone responsiveness after adrenalectomy may result from changes in adenosine metabolism or release.
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PMID:Alterations in response of rat white adipocytes to insulin, noradrenaline, corticotropin and glucagon after adrenalectomy. Correction of these changes by adenosine deaminase. 21 18

Systematic pituitary evaluation was performed in four patients suspected of having Sheehan's syndrome. A sequential pituitary stimulation test, consisting of insulin-induced hypoglycemia followed by stimulation of gonadotropin-(GnRH) and thyroid-releasing hormone (TRH), a metyrapone test, and adrenocorticotropic hormone (ACTH) stimulation test, was performed. All four patients failed to develop a normal increase in serum growth hormone, cortisol, and prolactin (PRL) following insulin-induced hypoglycemia. All patients demonstrated a blunted PRL, follicle-stimulating hormone, and luteinizing hormone response to the combination of GnRH and TRH. Although thyroid stimulating hormone (TSH) response was impaired in all patients, two patients had normal T3 resin uptake and thyroxine, demonstrating minimal TSH reserve maintaining normal baseline free thyroxine index. Metyrapone administration was followed by no increase in 11-deoxycortisol or 17-ketogenic steroids, thereby adding no additional information to the hypoglycemia stimulation. ACTH infusion revealed normal adrenal cortisol response. In conclusion, in patients with suspected postpartum hypopituitarism, a complete pituitary function investigation can be done in a short time by using the described pituitary sequential stimulation test.
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PMID:Diagnosis of Sheehan's syndrome using a sequential pituitary stimulation test. 21 51

myo-Inositol deficiency in rats produced an overaccumulation of triacylglycerols in the liver due to stimulated lipolysis in the adipose tissue (Hayashi, E., Maeda, T. and Tomita, T. (1974) Biochim. Biophys. Acta 360, 134--155). The mechanism of the enhancement in lipolysis has now been investigated. The lipolytic response to adrenalin, corticotropin and insulin of the epididymal adipose tissue did not change due to the deficiency, but hormone-sensitive lipase activity, plasma adrenalin level and blood pressure were higher in the deficient rats. Adrenalectomy had no influence, but administration of sympathetic nervous blockers (reserpine, hexamethonium and bupranolol) inhibited the liver lipid deposition and an increase of serum free fatty acids in the deficient rats. These results indicate that the enhancement in lipolysis is mediated by an excitation of sympathetic nerve terminals innervating in the adipose tissues.
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PMID:The effect of myo-inositol deficiency on lipid metabolism in rats. III. The mechanism of an enhancement in lipolysis due to myo-inositol deficiency in rats. 21 37

A clonal cell line that responds to insulin and to lipolytic hormones has been established from the epididymal fat pad of the C57BL/6J ob/ob mouse. This line, designated ob 17, has a doubling time of 12.5 or 19 hr in 10% or 1% fetal calf serum, respectively. It presents a heterogeneous chromosome number with 40% of the cells containing 35-44 chromosomes and expresses the characteristic H2-LA antigen. After cessation of growth, ob 17 cells accumulate droplets of triglycerides; this accumulation occurs to a significant extent even in the absence of insulin normally added after confluence. Lipoprotein lipase activity is negligible in exponentially growing cells but appears at its maximal level just after confluence with or without insulin. Acid:CoA ligase and acylCoA:diglyceride acyltransferase develop later than lipoprotein lipase. The appearance of lipolytic and lipogenic enzymes, but not of triglycerides, seems to be independent of the presence of lipoproteins or of unesterified fatty acids in the culture medium. Therefore, the differentiation program becomes operative when growth is arrested, and differentiation occurs, providing a source of exogenous lipids. Differentiated ob 17 cells in which endogenous triglycerides have been prelabeled on the fatty acid moiety do respond to epinephrine and corticotropin by release of radioactive fatty acid. This lipolytic response is counteracted by prior addition of insulin. The ob 17 cell line appears to be a useful model for study of growth and differentiation of adipose cells as compared to preadipocyte cell lines from the nongenetically obese mouse.
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PMID:Establishment of preadipocyte clonal line from epididymal fat pad of ob/ob mouse that responds to insulin and to lipolytic hormones. 21 11

The hypothalamic pituitary adrenocortical function has been studied in 16 patients operated from pituitary tumors (13 adenomas; 3 craniopharyngiomas). Comparisons have been made between corticotropin and cortisol response to lysine vasopressin, insulin induced-hypoglycemia and metyrapone IV and per os. Among these different stimulating tests, insulin induced hypoglycemia and metyrapone per os seem to give the more accurate informations metyrapone per os being more convenient because harmless. Three different groups of patients have been distinguished : one without adrenocortical deficiency; one with a complete deficiency and a third group with a partial deficiency. Correlations have been studied between the degree of the adrenocortical deficiency, the volume of the tumor and the presence of the absence of other anterior pituitary dysfunctions.
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PMID:[Study of the hypothalamo-pituitary adrenal function in 16 patients after surgery for pituitary tumor (author's transl)]. 21 1

In idiopathic or generalized epilepsy, serum glucose and cholesterol concentrations tend to be low, especially just before the seizure. Glucose tolerance curves are abnormal and variable. The electrolyte balance is disturbed, and epileptics tend to go readily into alkalosis. Serum [Na+] is usually unaffected, but [K+] is normal to low between attacks and increases during and after the seizure. Serum [Cl-] is usually high just before the seizure. Epileptics are generally mildly hypocalcemic, especially in the period before the seizure. Serum urea and nonprotein nitrogen values are low between paroxysms but increase after the seizure. Serum protein concentration is usually normal. Stress, which releases epinephrine and corticotropin, results in high serum citrate concentration, which probably contributes to decreased serum [Ca2+] just before a seizure. In the healthy individual, any increase in serum citrate is accompanied by increasing [Ca2+]. In the rabbit, convulsions can be induced with corticotropin, a result of increased serum citrate concentration coupled with a decrease in [Ca2+]. The net result is severe hypo-ionic-calcemia. A similar phenomenon has been reported in a few humans. Administration of insulin causes serum citrate concentrations to decrease. Apparently, the dynamic system that controls glucose and lipid metabolism, and thus electrolyte balance, through the hormones epinephrine, corticotropin, insulin, glucagon, calcitonin, and parathormone, is abnormal in the epileptic.
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PMID:Clinical biochemistry of epilepsy. I. Nature of the disease and a review of the chemical findings in epilepsy. 22 Nov 36

The common obesity of middle age presents a set of features that strongly resembles the cardinal symptoms of Cushing's syndrome: obesity of the face (moon face), upper back (buffalo hump) and trunk (pot belly) accompanied by signs of protein-wasting. In non-obese individuals who remain at a constant weight throughout life, the proportion of adipose tissue increases with age at the expense of lean tissue loss. Thus, a mild version of Cushing's syndrome may be part of the normal aging process. A more intense version of this process may occur in overweight adults. Excess and chronic activity of two pituitary hormones may contribute to this adiposity. Both hormones are produced in the same pituitary cell by cleavage from a common large precursor known as pro-opiocortin. One hormone is adrenocorticotrophin (ACTH), which stimulates the release of the glucocorticoid hormones. These hormones promote the conversion of bodily proteins to glucose (gluconeogenesis). The other pituitary hormone is beta-endorphin, a stimulant of appetite that causes the release of insulin. This pancreatic hormone promotes the conversion of glucose and fatty acids to triglycerides (lipogenesis). Three different etiologies are suggested for the excessive and chronic action of these two pituitary hormones: tumors that increase the number of cells that synthesize pro-opiocortin; mutant strains that produce excessive amounts of ACTH and beta-endorphin such as the genetically obese mouse (ob/ob) and rat (fa/fa); and an age-determined shift in the type of cleavage enzymes present in the pro-opiocortin cell that favors ACTH and beta-endorphin production.
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PMID:The obesity of middle age: a common variety of Cushing's syndrome due to a chronic increase in adrenocorticotrophin (ACTH) and beta-endorphin activity. 22 74

We describe a liquid-chromatographic procedure for separating and measuring cortisol and 11-deoxycortisol in serum. We quantitated these steroids in patients who were undergoing various tests of pituitary and (or) adrenal function and compared the results with those obtained by two radioimmunoassays done in two different laboratories. Results of 48 tests done in 37 functionally normal humans are presented. Cortisol values for sera collected in the morning as determined by liquid chromatography were (mean +/- SD) 134 +/- 54 micrograms/L. Serum cortisol concentrations increased from 136 +/- 65 to 321 +/- 80 micrograms/L 60 min after injecting synthetic corticotropin and increased from 107 +/- 46 to 242 +/- 31 micrograms/L after insulin-induced hypoglycemia. Serum cortisol decreased from 142 +/- 49 to 26 +/- 20 micrograms/L after oral administration of metyrapone, while 11-deoxycortisol increased from less than 10 to 210 +/- 53 micrograms/L. Serum cortisol measured less than 10 micrograms/L the morning after oral ingestion of dexamethasone. Results of the dynamic tests of adrenal function correlated well with previously reported studies. However, the cortisol values obtained by our technique were generally lower than those obtained by radioimmunoassay, possibly owing to lack of specificity of the latter methods used here for comparison. In contrast, values for 11-deoxycortisol were the same by both methods. The present studies confirm the usefulness of liquid chromatography for measuring these two steroids in serum during tests of pituitary and adrenal function. Future refinements of the technique should continue to increase its clinical applications.
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PMID:Serum cortisol and 11 deoxycortisol by liquid chromatography: clinical studies and comparison with radioimmunoassay. 22 58


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