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Results 501 - 550 of 718
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Ho T L - - 1984
The effect of combination of the hydrophilic aza-Gly substitution (NHNHCO) at position 10 with hydrophobic, unnatural D-amino acids in position 6 on the potency of luteinizing hormone-releasing hormone (LH-RH) analogues has been investigated. Previously the aza-Gly residue was shown to provide protection from enzymatic cleavage and lead to potency increases ...
Schuh B A - - 1984
Two monophagous sawflies,Neodiprion dubiosus andN. rugifrons, actively avoid feeding on the current season's needles of jack pine,Pinus banksiana, while the polyphagousN. lecontei feeds indiscriminately on foliage of all age classes. Bioassay studies with needle extracts indicate thatN. dubiosus andN. rugifrons larval feeding preference is governed by a group of tricyclic ...
Szirtes T - - 1984
Twenty-four thyrotropin-releasing hormone (TRH) analogues containing mainly aliphatic amino acids in position 2 were synthesized and tested for central nervous system (CNS) and hormonal (TSH) activity. Application of the pentafluorophenyl ester method in the syntheses resulted in optimal yields and high purity of the products. The neutral tripeptides pGlu- Nva ...
Menéndez-Patterson A - - 1984
Significant amounts of immunoreactive glucagon (IRG) were determined in acid-ethanol and acid-saline extracts of human thyroid. Glucagon content of healthy thyroid, expressed as ng/g wet tissue or pg/mg protein, was significantly greater after an acid-alcohol extraction than after an acid-saline one. Furthermore IRG in acid-alcohol extracts of healthy tissue was ...
Hidiroglou M - - 1984
The relationship of zinc to morphologic, physiologic, and metabolic functions in the male reproductive system are summarized, and gaps in current understanding are pointed out. Semen and its constituents generally contain high zinc, although concentrations vary among animals and species; the relationships between zinc and fertility of semen is unclear. ...
Conn P M - - 1984
The observations in recent years that gonadotropin-releasing hormone ( pyroGlu1 -His2-Trp3- Ser4 -Tyr5- Gly6 -Leu7-Arg8-Pro9- G ly10NH2 [GnRH]) has considerable clinical efficacy as a contraceptive, an ovulation-inducing agent, and a drug that is useful in the therapy of a number of diseases are owed in no small part to advances ...
Ichihara K - - 1984
The concentrations and hormonal forms of CCK and VIP have been determined in extracts of the brain and duodenum of the developing and adult pig. In methanol extracts of the brain cortex, the single hormone form, CCK8, increased from 130 +/- 20 (Mean +/- SEM) pmol/g at birth to an ...
Gennari C - - 1984
The effects of two different glucocorticoids, prednisone and deflazacort, (an oxazoline derivative of prednisolone) on bone metabolism were analyzed in 10 patients with disorders that required glucocorticoid therapy. Significant elevations in blood immunoreactive parathyroid hormone, alkaline phosphatase and urinary calcium, phosphate, hydroxyproline and nephrogenous cyclic AMP were observed during prednisone ...
Audhya T - - 1984
Thymopoietin, a 49 amino acid polypeptide hormone of the thymus discovered by its effect on neuromuscular transmission, was later shown to induce T-cell differentiation and to affect immunoregulatory balance. A radioimmunoassay for thymopoietin revealed a crossreaction with a product found in spleen and lymph node but not other tissues. This ...
Koizumi Y - - 1984
A single oral dose of mefenamic acid significantly depressed plasma thyroxine (T4) within 3 h in man. Similarly, mefenamic acid depressed plasma T4 within 3 h in thyroidectomized, T4-maintained rats. Plasma free fractions of T4 and tri-iodothyronine (T3) increased significantly after a single oral administration of mefenamic acid in man. ...
MacDonald B R - - 1984
Local production of prostaglandins by osteoblasts may be important in controlling the bone resorbing activity of some hormones which have receptors on osteoblasts. We have demonstrated that osteoblast-like cells derived from human bone can incorporate [14C]arachidonic acid into phospholipids and synthesise immunoreactive PGE. Parathyroid hormone increases both the release of ...
Nestor J J JJ - - 1984
A novel class of heterocyclic aromatic amino acids based on the 3-(2-benzimidazolyl)alanine system has been generated by chiral synthesis from D- or L-aspartic acid. The use of variously substituted o-phenylenediamines for condensation with the beta-carboxyl function of alpha-benzyl N-(benzyloxycarbonyl)-D-aspartate has led to a series of amino acids of graded hydrophobicity ...
Hoath S B - - 1984
We have shown a positive correlation between the epidermal growth factor concentration in neonatal mouse skin and prior treatment with thyroxine (T4) or triiodothyronine (T3). The results of the present study indicate similar activity of other levorotatory iodothyronine analogues and suggest the following scale of decreasing potency: T3, triiodothyroacetic acid, ...
Gäde G - - 1984
Locust adipokinetic hormones I (AKH I) and II (AKH II) are separated by reversed-phase high-performance liquid chromatography using a mu-Bondapak phenyl column with a trifluoroacetic acid/acetonitrile gradient. The eluant was monitored at 210 nm and the hyperlipaemic activity was detected using a bioassay. The amino-acid composition of AKH II was ...
Kim P S - - 1984
Thyroglobulins (Tgs) were purified from five species (rat, chicken, turtle, frog, and goldfish), each representing a different vertebrate class. On reduction with mercaptoethanol, each Tg produced five major iodopeptides, designated A-E, with ranges of estimated molecular mass, in kilodaltons (K), as follows: A, more than 300K; B, 210-280K; C, 30-42K; ...
Singh S P - - 1984
An exposure of genetically gibberellic acid-insensitive isolated wheat aleurone tissue/deembryonated seeds to low temperature for 20 hours prior to addition of exogenous gibberellic acid results in a significant increase in sensitivity to gibberellic acid. The results may reflect a low temperature-induced increase in hormone receptor sites and could have important ...
Quackenbush L S - - 1984
Gamma-aminobutyric acid (GABA) blocked concentration of the pigments in melanophores and erythrophores of intact crabs. GABA blocked the release of pigment concentrating hormones from the isolated eyestalk. Octopamine (OA) blocked black pigment dispersion in intact crabs, but did not affect red pigment dispersion or concentration. OA blocked the release of ...
Yamashiro D - - 1984
Two analogs of the red pigment-concentrating hormone (RPCH) have been synthesized by the solid-phase method: [Thr6]-RPCH (I) and [Tyr4, Thr6]-RCPH (II). Analog I has the same amino acid composition as the second adipokinetic hormone (AKH-II) isolated from locust corpora cardiaca. Bioassay for lipid-mobilizing activity in adult male locusts gave the ...
Martyn P - - 1984
Progesterone up to 15.9 mumol/l progressively suppressed prolactin-stimulated fatty acid synthesis in cultured mammary explants from 11-day pseudopregnant rabbits, but did not influence the proportion of fatty acids of medium chain length (C8:0-C12:0). Greater sensitivity to progesterone inhibition was observed at the low end of the ranges of corticosterone (29 ...
Mason G A - - 1983
The acute effects of administration of 4 excitatory amino acids (n-methyl-DL-aspartic acid (NMA), kainic acid (KA), ibotenic acid (IA) and quinolinic acid (QA] on the serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), growth hormone (GH) and prolactin (PRL) were studied in the rat. NMA-treated rats exhibited increased serum ...
Freeman H C - - 1983
Blood samples were taken from fourteen sexually mature (ripe) male Atlantic salmon (Salmo salar), eight from the acidic Westfield river (pH 4.7) and six from the less acidic (pH 5.6) Medway river to determine if there is any difference in sex hormone production in the fish in the two rivers. ...
Baker F C - - 1983
The metabolism of [3H]farnesol was studied in cell-free preparations of corpora allata from the tobacco hornworm, Manduca sexta, to assess the role of this presumed biosynthetic precursor of juvenile hormone (JH) III. A reversed-phase ion-pair liquid chromatographic (RP-IPC) procedure was devised to separate farnesol from several potential intermediates in its ...
Pekary A E - - 1983
Thyrotropin-releasing hormone (TRH) immunoreactivity occurs in high concentration within the rat prostate. Previous studies have shown that the immunoreactive species consists of more than one TRH-like tripeptide which cross-reacts in the TRH radioimmunoassay. The component which was highly retained during cation exchange chromatography was subjected to a preparative scale isolation, ...
Palmer T N - - 1983
Vasopressin and angiotensin II inhibited lipogenesis (measured with 3H2O) in hepatocytes from fed rats. Inhibition was also observed with hepatocytes from fed rats which had been depleted of glycogen in vitro and incubated with lactate + pyruvate (5 mM + 0.5 mM) as substrates. The inhibitory actions of the hormones ...
Atkinson C - - 1983
The dynamic interactions of the body's response to stress are extremely complex and can best be understood within the context of an information flow diagram. In this paper such a model is developed from the biochemical equations of glycolysis and from relevant hormonal and behavioral relations. In response to a ...
Shapiro J P - - 1983
Adipokinetic hormone, a decapeptide isolated from the locust, stimulates mobilization of diacylglycerols from the locust fat body and loading of the lipid transport protein, lipophorin. Injection of the synthetic locust adipokinetic hormone into a sphinx moth, Manduca sexta, causes lipid loading of lipophorin. The lipophorin decreases in density from 1.11 ...
Wehrenberg W B - - 1983
The biological potency of the synthetic replicates of three peptides isolated from a human pancreatic tumor with growth hormone releasing activity and rat hypothalamic growth hormone-releasing factor was evaluated in conscious freely-moving rats and anesthetized rats. All 4 peptides are equipotent on a molar basis in their ability to stimulate ...
Liepnieks J J - - 1983
The trinitrophenyl group was specifically introduced into the epsilon-amino group of glucagon by reaction of N alpha-citraconyl glucagon with trinitrobenzenesulfonic acid. The N alpha-citraconyl blocking group was subsequently removed by acid treatment yielding N epsilon-trinitrophenyl glucagon which was purified by anion-exchange chromatography. The derivative showed less secondary structure as measured ...
Isaac R E - - 1983
The four major ecdysteroid (insect moulting hormone) conjugates present in the newly laid eggs of the desert locust, Schistocera gregaria, have been purified by reversed-phase and anion-exchange high-performance liquid chromatography. The steroid moieties were identified as ecdysone, 2-deoxyecdysone, 20-hydroxyecdysone and 2-deoxy-20-hydroxyecdysone. Phosphate analysis of acid-hydrolysed samples showed a steroid:phosphate ratio ...
Ishibashi Y - - 1983
Two hormones, tremerogens A-9291-I and A-9291-II, that induce conjugation tube formation in a-type cells of Tremella brasiliensis were isolated from the culture filtrate of A-type cells. Both hormones are peptides and they have similar amino acid compositions. The N-terminal amino acids of these peptides are aspartic acid or asparagine.
Singh J - - 1983
The effects of amino acids, exogenous islet hormones and acetylcholine on cyclic nucleotide metabolism and amylase secretion in the isolated mouse pancreas have been investigated. The changes in levels of adenosine 3',5'-cyclic monophosphate (cyclic AMP) and guanosine 3',5'-cyclic monophosphate (cyclic GMP) were measured at different times during exposure of pancreatic ...
Snyder G D - - 1983
Anterior pituitary cells were incubated in the presence of luteinizing hormone-releasing hormone and one of three inhibitors of arachidonic acid metabolism:indomethacin, an inhibitor of the cyclooxygenase system; nordihydroguaiaretic acid, an antioxidant that inhibits lipoxygenase; and icosatetraynoic acid, an acetylenic analogue of arachidonic acid that blocks all known pathways of arachidonic ...
Gallo G - - 1983
Insulin and dexamethasone greatly stimulate the incorporation of 3H-orotic acid into RNA. Such a stimulation is associated to an increase in the uptake of the labelled precursor into the acid soluble fraction as well as in the the specific radioactivity of the nucleoside plus nucleotide pool suggesting that hormone supplementation ...
Baumann G - - 1983
Human GH (hGH) extracted from pituitary glands consists of several molecular forms. Monomeric pituitary forms include the single chain 22,000-dalton polypeptide (22K; hGH-B), a 20,000-dalton variant with a 15-amino acid deletion (20K), 3 proteolytically cleaved 2-chain forms (hGH-C, -D, and -E), 2 deamidated forms, an acetylated form (fast hGH), and ...
Malejka-Giganti D - - 1983
Metabolic or synthetic N-hydroxylation of N-arylamides yields N-arylacylhydroxamic acids considerably more carcinogenic for the rat mammary gland than the parent amides both by systemic and topical administration. The size of the aryl moiety, the position of the nitrogen relative to the aryl moiety and the type of acyl group are ...
Dickson A J - - 1983
1. The effectiveness of gluconeogenic precursors in hepatocytes isolated from 18 day old chick embryos is:Lactate much much greater than pyruvate greater than alanine = glutamine greater than glycerol and other amino acids. This result is qualitatively and quantitatively similar to hepatocytes isolated after hatching. 2. In the presence of ...
Chauvet M T - - 1983
The neurohypophysial hormones of the eastern gray kangaroo (Macropus giganteus) have been isolated through molecular sieving and paper chromatoelectrophoresis. One oxytocin-like and two vasopressin-like peptides have been found. These peptides have been characterized by amino acid analysis. Mesotocin ([Ile8]-oxytocin), has been identified both by amino acid composition and by behavior ...
Aloni R - - 1982
The differentiation of secondary xylem fibers was studied in cultured hypocotyl segments of Helianthus annuus L. It is shown that cytokinin is both a limiting and controlling factor in the early stages of fiber differentiation. In the absence of kinetin or zeatin, there was no fiber differentiation. However, cytokinin could ...
Hou-Yu A - - 1982
The hypothalamo-neurohypophysial system, containing the hormones oxytocin (OT) and vasopressin (VP) and their associated carrier proteins, the neurophysins (NPS), has been the subject of extensive investigation for more than 40 years. This system has been reinvestigated during the last decade by application of immunocytochemical methods employing the rabbit antisera to ...
Horvath A - - 1982
As part of our studies on the design of more potent antagonists of the LH-RH (luteinizing hormone-releasing hormone) decapeptide, twelve new highly soluble D-Arg6-analogs have been synthesized. These peptides contain modifications in position 1 and are typified by the general formula (N-acetyl-X1, D-p-Cl-Phe2, D-Trp3, D-Arg6, D-Ala10) LH-RH. We have found ...
Camargo A C - - 1982
1. The site of hydrolysis of rabbit brain endo-oligopeptidase B acting on luteinizing hormone-releasing hormone (LH-RH) was determined by isolating the products by chromatography on Aminex A-5 resin developed with pyridine-acetic acid buffer. The products [des-Gly-NH2(10)]-LH-RH, glycinamide and unhydrolyzed LH-RH were identified and shown to be homogeneous by amino acid ...
King J A - - 1982
Avian luteinizing hormone-releasing hormone (LH-RH) has been isolated from 249,000 chicken hypothalami and shown to differ structurally from mammalian hypothalamic LH-RH. Purification was achieved by acetic acid extraction, anti-LH-RH affinity chromatography, and cation exchange and reverse phase high performance liquid chromatography. The isolated peptide eluted as a single peak on ...
O'Connell M - - 1982
We have investigated the effect of FFA on the RIA of rT3 because of our previous findings of a correlation between serum rT3 values and increased FFA concentrations during prolonged exercise and reports of interference by FFA in other thyroid hormone assays. Apparent rT3 values increased by 19% and 34% ...
Findlay D M - - 1982
125I-labelled calcitonin and 125I-labelled epidermal growth factor (EGF) bound to T 47D breast cancer cells at 37 degrees C in a manner that became increasingly resistant to removal by acid pH. Bound 125I-labelled EGF became resistant to acid removal more rapidly than did bound 125I-labelled calcitonin. The shift from acid ...
Madias N E - - 1982
Two recent reports have made the provocative suggestion that parathyroid hormone (PTH) and, by implication, bone play a critical role in the early phase of acid buffering. The purpose of the present study was to investigate the effect of PTH on the acute buffering process by examining the influence of ...
Ryan K J - - 1982
The formation of estrogens in mammals via aromatase involves the relatively unique capacity to form an aromatic ring de novo in contrast to most other aromatic substances (essential amino acids) which are obtained only in the diet. The reaction is the only example of a cytochrome P450 system which resides ...
Beynen A C - - 1982
This paper presents a review of our current knowledge of short-term regulation of triacylglycerol metabolism by insulin and glucagon in isolated rat hepatocytes. Insulin is devoted to rapidly improve the lipogenic climate of the hepatocyte. The hormone stimulates glycolysis, the conversion of pyruvate into acetyl-CoA, the synthesis of fatty acids ...
Arakawa T - - 1982
Concentrations of bound amino acids in urine were found to be markedly higher in infants than in children over 4 years of age. And it was also found that bound amino acid levels in plasma were increased in infants and young children than in adults. Urinary excretion of bound amino ...
Hurpet D - - 1982
The hypothalamo-neurohypophyseal hormones of the brush-tailed possum (Trichosurus vulpecula) have been purified through molecular sieving and paper chromatoelectrophoresis. Two peptides have been isolated, one with pressor property, the other with uterotonic activity. The pressor hormone has been identified as arginine vasopressin by amino acid composition and amino acid sequence. The ...
Malejka-Giganti D - - 1981
This report describes activation of certain N-aryl-acetamides and N-arylacetohydroxamic acids and its relationship to mammary gland tumorigenesis. Evidence is presented that metabolic activation of N-2-fluorenylacetamide (2-FAA) by mixed function oxidase of liver microsomes is the primary requirement for tumor induction in the mammary gland by this compound in young adult ...
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