Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment of unanesthetized castrated adult male rats every 3 h for 48 h with either 5 microgram of arginine vasotocin (AVT) and/or 1 microgram luteinizing hormone-releasing hormone (LRH) caused a significant inhibition of plasma levels of luteinizing hormone (LH) and compared to castrated control rats receiving diluent only. However, the intravenous (iv) injection of 1 microgram of AVT into urethane-anesthetized male rats which had been castrated for 0, 24 or 48 h did not affect plasma levels of LH at 10, 20 or 60 min following injection compared to their respective diluent-treated castrated control rats. Similarly, the iv injection of either 100 ng, 1 microgram or 10 microgram AVT was unable to acutely affect plasma levels of LH in intact male rats. Following the iv injection of 2 doses of 50 ng LRH spaced 1 h apart in anesthetized castrated male rats, 2 peaks of equal magnitude in plasma LH were noted. Castrated rats treated with 2 injections spaced 1 h apart of LRH + AVT had significantly higher plasma levels of LH than did rats treated with LRH alone. In subsequent studies, both AVT and arginine vasopressin were observed to augment the plasma response of LH to an injection of LRH whereas oxytocin had no effect. A single injection of AVT + LRH significantly augmented the plasma titers of LH compared to levels observed in LRH-treated control rats as did a second injection 1 h later. The administration of cyproterone acetate sc for 2 days by itself had no effect on plasma LH but in conjunction with LRH caused a marked rise in plasma LH compared to intact rats treated with LRH alone. AVT in combination with LRH and cyproterone acetate caused a significant elevation in plasma LH at 60 min post-injection when compared to plasma levels of rats treated with LRH alone or the combination of LRH and cyproterone acetate. It is concluded that acute intravenous injections of AVT augment the LH-releasing activity of LRH; chronic treatment for 48 h, however, with LRH + AVT leads to a significant depression of plasma LH perhaps due to an exhaustion of the releasable pool of LH in the anterior pituitary.
Mol Cell Endocrinol 1979 Apr
PMID:Interaction of luteinizing hormone-releasing hormone, cyproterone acetate and arginine vasotocin on plasma levels of luteinizing hormone in intact and castrated adult male rats. 37 36

When in the primeval atmosphere ammonia approached exhaustion, bacteria resembling clostridia developed mechanisms for nitrogen fixation. The fixation was continued by the photosynthetic bacteria. In the later, oxidizing, atmosphere the combined activities of the nitrificants and the denitrificants could lead to a large-scale cyclic regeneration of free nitrogen. The possibility of a descent of the nitrificants from hypothetical photosynthetic bacteria, which used ammonia as electron donor, is discussed. The anoxygenic atmosphere contained no nitrate, and therefore neither nitrate fermentation nor nitrate respiration were precursors of aerobic respiration. This evolved from photosynthesis. In nitrate fermentation, nitrate serves only as an incidental electron acceptor; this process is merely an evolutionary sideline. Nitrate respiration evolved from aerobic respiration. While in present conditions the reaction of nitrogen with oxygen and water to give nitrate is exergonic and possibly occurs at a low rate, the antagonistic action of the denitrificants maintains the stationary concentrations of nitrogen and oxygen in the air.
J Mol Evol 1975 Dec 31
PMID:The history of inorganic nitrogen in the biosphere. 76 87

We have recently shown that a triacylglycerol (TG)-fatty acid cycle is operating in rat myocardial cells incubated in a hypoxic, glucose-containing incubation medium (Myrmel et al., 1991a). In the present study we investigated whether this cycle occurred in hypoxic, glucose-deprived myocytes, and whether high TG levels would increase TG-fatty acid cycling and thereby energy consumption. Myocytes with elevated contents of TG were obtained from the hearts of streptozotocin-induced diabetic rats (diabetic myocytes) and from normal rat myocytes prepared in the presence of oleic acid (TG-loaded myocytes). The TG content of diabetic and TG-loaded myocytes prior to hypoxic incubations was more than two times higher (P < 0.05) than that of their respective controls (123.8 +/- 20.6 and 125.3 +/- 12.7 vs 56.8 +/- 6.0 and 58.6 +/- 9.4 nmol/10(6) cells, mean +/- S.E., n = 7). Only diabetic and TG-loaded myocytes expressed marked reductions in TG content during glucose free incubations. There were no differences in TG-fatty acid cycling between the various myocyte groups, calculated as the difference between glycerol output and the concomitant decrease in TG (range: 36.7 +/- 8.1- 48.9 +/- 9.7 nmol TG/10(6) cells.2h). Apparently, the cycle was continuous throughout the whole incubation period despite falling ATP levels, contracture (rounding up) of myocytes, as well as cessation of glycogenolysis after about 40 min incubation. The cellular content of glycerol-3-phosphate, known to control TG-fatty acid cycling, increased continuously and to the same extent throughout the 2 h incubation period. Futile energy consumption associated with TG-fatty acid cycling, amounted to approximately 30% of total cellular energy consumption for the whole incubation period. In conclusion, hypoxic glucose deprived rat myocytes show TG-fatty-acid cycling, even after cessation of glycogenolysis. The extent of cycling, and thus the energy cost associated with it, was not influenced by the initial level of TG in the myocytes. We propose that glycerol-3-phosphate needed to fuel the TG-fatty acid cycle after exhaustion of the glycolytic supply is derived from phospholipid degradation.
J Mol Cell Cardiol 1992 Aug
PMID:Triacylglycerol metabolism in hypoxic, glucose-deprived rat cardiomyocytes. 143 15

The response of non-differentiating bacteria to nutrient starvation is complex and includes the sequential synthesis of starvation-inducible proteins. Although starvation for different individual nutrients generally provokes unique and individual patterns of protein expression, some starvation stimulons share member proteins. Two-dimensional polyacrylamide gel electrophoresis revealed that the synthesis of a small (13.5 kDa) cytoplasmic protein in Escherichia coli was greatly increased during growth inhibition caused by the exhaustion of any of a variety of nutrients (carbon, nitrogen, phosphate, sulphate, required amino acid) or by the presence of a variety of toxic agents including heavy metals, oxidants, acids and antibiotics. To determine further the mode of regulation of the protein designated UspA (universal stress protein A) we cloned the gene encoding the protein by the technique of reverse genetics. We isolated the protein from a preparative two-dimensional polyacrylamide gel, determined its N-terminal amino acid sequence, and used this sequence to construct a degenerate oligonucleotide probe. Two phages of the Kohara library were found to contain the gene which then was subcloned from the DNA in the overlapping region of these two clones. The amino acid sequence, deduced from the nucleotide sequence of the uspA gene, shows no significant homology with any other known protein. The uspA gene maps at 77 min on the E. coli W3110 chromosome, and is transcribed in a clockwise direction. The increase in the level of UspA during growth arrest was found to be primarily a result of transcriptional activation of the corresponding gene. The induction was independent of the RelA/SpoT, RpoH, KatF, OmpR, AppY, Lrp, PhoB and H-NS proteins during stress conditions that are known to induce or activate these global regulators. The -10 and -35 regions upstream of the transcriptional start site of the uspA gene are characteristic of a sigma 70-dependent promoter.
Mol Microbiol 1992 Nov
PMID:Cloning, mapping and nucleotide sequencing of a gene encoding a universal stress protein in Escherichia coli. 145 57

A specific complex of proteins involved in bacteriophage T4 replication has been visualized by cryoelectron microscopy as distinctive structures in association with DNA. Formation of these structures, which we term "hash-marks" for their characteristic appearance in association with DNA, requires the presence of the T4 polymerase accessory proteins (the products of T4 genes 44, 45 and 62), ATP and appropriate DNA cofactors. ATP hydrolysis by the DNA-stimulated ATPase activity of the accessory proteins is required for visualization of the hash-mark structures. If ATP hydrolysis is stopped by chelation of Mg2+, by dilution with a non-hydrolyzable ATP analogue, or by exhaustion of the ATP supply, the DNA-associated structures disappear within seconds to minutes, indicating that they have a finite and relatively short lifetime. The labile nature of the structures makes their study by more conventional methods of electron microscopy, as well as by most other structural approaches, difficult if not impossible. Addition of T4 gene 32 protein increases the number of hash-mark structures, as well as increasing the rate of ATP hydrolysis. Using plasmid DNA in either a native (supercoiled) or enzymatically modified state, we have shown that nicked or gapped DNA is required as a cofactor for hash-mark formation. Stimulation of the ATPase activity of the accessory proteins has a similar cofactor requirement. These conditions for the formation and visualization of the structures parallel those required for the action of these complexes in promoting the enzymatic activity of the T4 DNA polymerase, as well as the transcription of late T4 genes. Substructure in the hash-marks has been examined by image analysis, which reveals a variation in the projected density of the subunits comprising the structures. The three-dimensional size of the hash-marks, modeled as a solid ellipsoid, is consistent with that of the gene 44/62 protein subcomplex. Density variations suggest an arrangement of subunits, either tetragonal or trigonal, viewed from a variety of angles about the DNA axis. The hash-mark structures often appear in clusters, even in DNA that has a single nick. We interpret this distribution as the result of one-dimensional translocation of the hash-marks along the DNA after their ATP-dependent initial association with, and injection into, the DNA at nicks or gaps.
J Mol Biol 1992 Mar 20
PMID:Cryoelectron microscopic visualization of functional subassemblies of the bacteriophage T4 DNA replication complex. 153 38

Oxidative stress induced by cumene hydroperoxide was studied in cultured neonatal rat myocytes. A progressive increase of irreversible cell injury as determined by leakage of the cytoplastic enzyme alpha-hydroxybutyrate dehydrogenase (alpha-HBDH) from the cells was noted at concentrations ranging from 25-100 microM cumene hydroperoxide (incubation time 90 min). Cumene hydroperoxide-induced damage was reduced or prevented by several compounds: the application of Trolox C, a water-soluble vitamin E analogue, and of phospholipase A2 inhibitors chlorpromazine and (to a lesser extent) quinacrine prevented alpha-HBDH release. ICRF-159, a chelator of divalent cations, ascorbic acid, a potent antioxidant, and the cysteine protease inhibitor leupeptin did not reduce the cumene hydroperoxide-induced cytotoxicity. Detoxification of hydroperoxides by the glutathione peroxidase system results in an increased flux through the pentose phosphate shunt and loss of NADPH. Glucose inhibited the cumene hydroperoxide-induced alpha-HBDH release, probably by replenishing NADPH. These results indicate that cumene hydroperoxide, after exhaustion of the glutathione system, induces irreversible injury in cultured myocytes by a mechanism that depends to a large extent on deterioration of cellular membranes caused by lipid peroxidation and phospholipase activation.
J Mol Cell Cardiol 1990 Oct
PMID:Prevention of cumene hydroperoxide induced oxidative stress in cultured neonatal rat myocytes by scavengers and enzyme inhibitors. 209 37

A new depot formulation of the LHRH analogue Zoladex (goserelin acetate) has been developed which releases the drug over a period of at least 3 months as judged by measurement of drug content in depots at intervals after insertion in male rats and by the suppression of oestrogen secretion and oestrus in female rats. This formulation is based on the lactide/glycolide polymer system used for the standard 1-month Zoladex depot, but the dose has been increased to 10.8 mg and the characteristics have been modified to enable a longer release of drug to be achieved. Thirty-eight patients with histologically proven, locally advanced (stage T3 or T4) and/or metastatic prostate cancer were treated with this new longer acting LHRH analogue depot formulation containing 10.8 mg Zoladex. After initial increase of serum testosterone in the first week of therapy, castration levels were reached in all patients after 4 weeks and this was maintained for more than 14 weeks. At the time of depot exhaustion, when escape from castration levels of androgen occurred, all patients received a single injection of a standard 1-month depot containing 3.6 mg Zoladex which restored castration levels of androgen thus showing that the pituitary gland was again suppressed. The tolerance and acceptability of the longer-acting depot is high and comparable to the 1-month depot. Taking into account social and psychological factors, patients with advanced prostate carcinoma will soon be able to be treated with a longer acting LHRH depot formulation every 3 months an alternative of the 1-month depot now widely used clinically.
J Steroid Biochem Mol Biol 1990 Dec 20
PMID:A new extra long acting depot preparation of the LHRH analogue Zoladex. First endocrinological and pharmacokinetic data in patients with advanced prostate cancer. 214 7

The purpose of this investigation was to examine the role of intermediary metabolism in the maintenance of proton and charge balance in rainbow trout white muscle during exercise. With increasing power outputs, there was a greater reliance on white fibers and anaerobic processes for energy production. Glycogen content declined from a pre-exercise (pre-ex) level of 23 to less than 1 mumol/g following the exhaustive swim, with its greatest rate of decline occurring during the burst swim. Lactate accumulation reached a maximum of 43 mumol/g during the exhaustive swim. PCr declined from about 20 to less than 2 mumol/g at exhaustion with a concomitant accumulation of Cr. ATP decreased from about 7.3 to 2.7 mumol/g while inorganic phosphate and IMP increased to about 56 and 4.3 mumol/g, respectively. The intramuscular pH fell from 6.97 to 6.93 during the sustained swim, declining further to 6.65 during the burst swim and reaching a minimum of 6.56 at exhaustion. Exercise induced depletions of high energy compounds and accumulations of metabolic end products nearly stabilized the accompanying intracellular perturbations in charge and proton levels. Compensatory shifts in Na+, K+ and Cl- served to negate the residual imbalances such that electrical neutrality, membrane potential and pH were preserved.
Mol Cell Biochem 1987 Sep
PMID:The role of intermediary metabolism in the maintenance of proton and charge balance during exercise. 282 1

The effect of fatigue (running to exhaustion) on the Vmax activity of the key glycolytic enzymes measured at saturating substrate concentrations in muscles, liver and brain of sedentary and trained (running on a treadmill one h/day at 20 m/min, five days/week for six months) female Zucker fatty rats and their lean littermates was investigated. In the sedentary rats, fatigue increased the activity of phosphofructokinase (PFK) in the red vastus muscle by 82% in lean, and 120% in obese rats. In the trained rats, fatigue increased PFK activity by 28% in the white vastus muscle of lean rats. In the lean animals, hexokinase (HK) activity was decreased by 26% in the red vastus of sedentary rats, and by 29% in the white vastus of trained rats upon fatiguing. Pyruvate kinase (PK) activity was also decreased by 29% in the white vastus of fatigued lean animals. Training by itself had no effect on the activity of glycolytic enzymes, except PK activity which was increased by 27% in the cortex of the lean animals. It is concluded that in the Zucker rat, these glycolytic enzymes may play a differential role in regulating glycolysis during exercise and fatigue; the extent of their involvement differs depending upon the type of tissue studied and exercise. In view of the reported short half-life (7-17 h) of PFK and its covalent modification, it is suggested that the total content and/or phosphorylation status of the enzyme may be affected in animals subjected to long-term fatigue.
Mol Cell Biochem 1988 Jun
PMID:Effect of exercise on glycolytic enzymes of Zucker fatty rats. 297 74

The purpose of this study was to examine the Ca2+-Mg2+ myofibrillar ATPase and protein composition of cardiac and skeletal muscle following strenuous activity to voluntary exhaustion. Sprague-Dawley rats (200 g) were assigned to a control and exercised group, with the run group completing 25 m.min-1 and 8% grade for 1 hour. Following activity, the myocardial Ca2+-Mg2+ myofibrillar ATPase activity -pCa relationship had undergone a rightward shift in the curve. Electrophoretic analysis revealed a change in the pattern of cardiac myofibrillar protein bands, particularly in the 38-42 Kdalton region. Enzymatic analysis of myofibrillar proteins from plantaris muscle, revealed no change in Ca2+ regulation following exercise. Electronmicrographic and electrophoretic analysis revealed extensively disrupted sarcomeric structure and a change in the ratio of several plantaris myofibrillar proteins. No difference was observed for myosin: Actin: tropomyosin ratios; however a dramatic reduction in 58 and 95 Kdalton proteins were evident. The results indicate that prolonged running is associated with similar responses in cardiac and skeletal muscle myofibrillar protein compositions. The abnormalities in myofibrillar ultrastructure may implicate force transmission failure as a factor in exercised-induced muscle damage and/or fatigue.
Mol Cell Biochem 1988 Sep
PMID:Influence of exercise on cardiac and skeletal muscle myofibrillar proteins. 297 50


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