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)

Isolated adrenal cells from Vitamin E-deficient and control rats were prepared by a trypsin digestion method. Cyclic adenosine 3',5'-monophosphate (cyclic AMP) formation was studied in response to adrenocorticotropin (ACTH) in the presence and absence of ascorbate by measuring the conversion of prelabeled adenosine 5'-triphosphate [14C]ATP to cyclic [14C]AMP. Ascorbate (0.5 mM) inhibited ACTH-induced cyclic [14C]AMP formation in adrenal cells isolated from Vitamin E-deficient rats but had no effect in the control cells. The inhibitory effect of ascorbate on ACTH-induced cyclic AMP formation in Vitamin E-deficient rats decreased as the concentration of ACTH increased. In Vitamin E-deficient rats ascorbate inhibited ACTH-induced cyclic [14C]AMP formation after 30 min of incubation. There was no further significant accumulation of cyclic [14C]AMP at 60 min or 120 min although in the absence of ascorbate cyclic [14C]AMP continued to be formed. The in vitro addition of alpha-tocopherol reduced the inhibition of ACTH-induced cyclic [14C]AMP formation by ascorbate in Vitamin E-deficient rats. These studies suggest that alpha-tocopherol and ascorbate may affect ACTH-induced cyclic AMP formation through interaction with the membrane-bound enzyme adenylate cyclase.
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PMID:Effect of ascorbic acid on ACTH-induced cyclic AMP formation and steroidogenesis in isolated adrenal cells of vitamin E-deficient rats. 16 1

Dehydroascorbic acid is present in insignificant amounts in plant and animal tissue but appears in considerable amounts under various physiological and pathological conditions. It is found increased: in blood of patients suffering from infectious diseases; in blood and tissues of thyrotoxic patients; in blood after injection of thyroxin, corticotropin and cortisone. In all the above conditions there is concomitant decrease in L-ascorbic acid and glutathione values of blood and tissues. Dehydroascorbic acid, however, disappears after continued administration of a high dose of ascorbic acid. The accumulation of dehydroascorbic acid seems to be an indication of ascorbic acid deficiency. The extreme sensitivity of the ascorbate system to physiological changes is suggestive of a major biochemical role for this redox system. Accumulated evidences indicate that dehydroascorbic acid possible control cell division.
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PMID:Physiological role of dehydroascorbic acid. 40 55

We performed a histochemical study using the Alcian blue-PAS staining method (for mucopolysaccharide), vitamin C, Sudan black (for lipids), and methyl green-pyronine (for nucleic acid). For the study, we utilized 105 male Wistar rats weighing 280-300 gms. Thirty rats comprised the control group, and 75 comprised the study group. Rats in the study group received a single, acute intracardiac dose of met-enkephalin (100 microliters of 50% met-enkephalin solution) and were sacrificed at 15, 30 and 60 minutes following injection, or a chronic intramuscular dose (50 microliters of 40% met-enkephalin solution). We observed that met-enkephalin caused histochemical changes in the rat testis, as evidenced by the accumulation of mucopolysaccharide (early in the study), cytoplasm lipid degeneration, changes in protein synthesis, and a fall in vitamin C stores (in seminal epithelium cell lines, as well as Leydig cells). These changes were more marked in the chronically than in the acutely-treated rats. The foregoing findings demonstrate that enkephalins (endogenous opiates) can cause profound metabolic changes in the rat testis that affect all its metabolic elements [proteins, lipids, polysaccharides and active substances (vitamins...)].
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PMID:[Effects of met-enkephalin on the testis. II. Histochemical study]. 262 83

Malondialdehyde (MDA) derivatives occur as normal constituents of rat and human urine. In a previous study, it was found that MDA excretion in rats is responsive to MDA intake and to certain factors that increase lipid peroxidation in vivo: vitamin E deficiency, iron administration and a high concentration of cod liver oil (CLO) fatty acids in the tissues. In the present study, the effect on MDA excretion of several additional dietary and endogenous factors was evaluated. The composition of dietary fatty acids had a major influence on MDA excretion in fed animals, being highest for animals fed n-3 fatty acids (20:5 and 22:6) from CLO, intermediate for those fed n-6 (18:2) acids from corn oil (CO) and lowest for those fed saturated acids from hydrogenated coconut oil (HCO). Diet was the main source of urinary MDA in all groups. Fasting produced a marked increase in urinary MDA, which tended to be higher in rats previously fed CLO. Fasting MDA excretion was not affected by the level of CO in the diet (5, 10 or 15%), indicating that feeding n-6 acids does not increase lipid peroxidation in vivo. Adrenocorticotropic hormone and epinephrine administration increased urinary MDA, further indicating that lipolysis either releases fatty acid peroxides from the tissues or increases the susceptibility of mobilized fatty acids to peroxidation. A decrease in fasting MDA excretion was observed in rats previously fed a high level of antioxidants (vitamin E + BHT + vitamin C) vs a normal level of vitamin E. MDA excretion increased following adriamycin and CCl4 administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Response of urinary malondialdehyde to factors that stimulate lipid peroxidation in vivo. 282 43

Peptidylglycine alpha-amidating activities from rat pituitary, brain and small intestine were compared, utilizing C-terminal analogues of vasoactive intestinal polypeptide (VIP), D-Tyr-Leu-Asn-Gly and D-Tyr-Asn-Gly, and C-terminal analogue of alpha-MSH, D-Tyr-Val-Gly. The three tissues had enzymic activities capable of converting the glycine-extended peptides to the corresponding alpha-amidated ones. In other words, all of three peptides could serve as substrates for the enzymes from both neural and gastrointestinal tissues. The activities were stimulated in the presence of copper and ascorbate; the optimal concentration of each cofactor was roughly equal for the three enzymes; similar pH profiles (a neutral pH optimum at 6.5-7 and another one at 8-8.5) were also observed. Desamide VIP-Gly was proved to be a potent inhibitor of the alpha-amidating activities from the tissues, but VIP was not, indicating that the alpha-amidating enzymes from these tissues in common have a recognition site for the C-terminal glycine of the glycine-extended precursor regardless of the length and nature of the sequence. No fundamental differences were observed between the catalytic properties of the alpha-amidating activities from these three tissues, raising the possibility that similar enzymes, which may or may not be a single species, are functioning in tissues that produce alpha-amidated polypeptides in vivo.
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PMID:Characterization of peptidylglycine alpha-amidating activities in rat pituitary, brain and small intestine using glycine-extended C-terminal analogues of vasoactive intestinal polypeptide as substrate. 323 97

Based on sequence data, rat and mouse pro-adrenocorticotropin (ACTH)/endorphin could give rise to joining peptide, a short acidic peptide that could terminate with a glutamic acid alpha-amide. Rat and mouse pituitary cells were found to cleave the pro-ACTH/endorphin precursor at an -Arg-Arg- site to produce primarily joining peptide-sized material. The amounts of joining peptide were approximately equimolar to the other major pro-ACTH/endorphin-derived products. Using antisera specific for the COOH-terminal modifications of joining peptide and three analytical approaches which separate amidated from glycine-extended forms of joining peptide, it was found that most of the joining peptide in murine anterior and intermediate pituitary was amidated. Identification of the amidated and glycine-extended forms of joining peptide was confirmed by amino acid analysis of the purified molecules. When anterior pituitary corticotrope tumor cells were grown in culture medium lacking ascorbate, there was no detectable ascorbate in the cells; nevertheless, a significant fraction of the joining peptide produced was alpha-amidated, indicating that production of alpha-amidated product was not totally dependent on ascorbate. The amidation state of the joining peptide produced by mouse corticotrope tumor cells was responsive to added ascorbate. Cells grown in medium containing ascorbic acid at the levels found in plasma concentrated the ascorbate to the levels normally found in pituitary tissue, and nearly all of the joining peptide produced was alpha-amidated. The amidation state of secreted joining peptide mirrored the amidation state of the joining peptide in the cells.
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PMID:Amidation of joining peptide, a major pro-ACTH/endorphin-derived product peptide. 372 67

Rat bone was extracted with KCl and Triton X-100, and a tartrate-resistant acid phosphatase activity was purified by protamine sulfate precipitation, ion-exchange chromatography (CM-cellulose), and gel filtration on Sephadex G-200 according to previously described procedures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining demonstrated a major band with an apparent monomer molecular size of approximately 14,000 Da. The enzyme is active with p-nitrophenylphosphate (p-NPP) but exhibits a 5- to 10-fold higher affinity towards several nucleotides of which ATP and ADP are the most readily hydrolyzed substrates based on kinetic studies. Based on sensitivity towards proteolytic treatment and detergent removal, as well as pH-optimum studies, a single enzyme was found to be responsible for activity towards nucleotide phosphates as well as p-NPP. This nucleotide tri- and diphosphatase constitutes around 15% of the total acid phosphatase activity in rat bone. The activity with ATP as substrate in contrast to that with p-NPP was inhibited in a noncompetitive fashion by MgCl2, sodium metavanadate, and p-chloromercuribenzoate. Enzyme activity with p-NPP and ATP is dependent on the presence of KCl and detergent and is activated by Fe3+ and ascorbate. The reported characteristics of the enzyme suggest that it functions as a unique membrane acid ATPase.
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PMID:Purification and characterization of a vanadate-sensitive nucleotide tri- and diphosphatase with acid pH optimum from rat bone. 623 50

Supply of the Chernobyl NPP staff and Slavutich children with vitamins and minerals has been examined in spring 1992. From 43 to 100% of people have moderate deficiency of vitamin C, B1, B2, B6 and folic acid, 6-61%--deep deficiency of these nutrients. Most of the people have insufficient supply with vitamins in the form of polyhypovitaminosis, i.e. combined deficiency of ascorbic acid and of 2 or 3 vitamins of the B group. Deficiency of 2 vitamins was found in 20% of adults of 3 vitamins in 37%, of 4 vitamins in 29% and of 1 vitamin in 10% of adults. Only 4% of examined adults are sufficiently supplied with all vitamins and none of children. Deficiency of 1 vitamin was found in 11% of children, of 2 vitamins in 15%, of 3 vitamins in 17%, of 4 vitamins in 35%, of 5 vitamins in 20% and of 6 vitamins in 2% of children. Supply of children with all vitamins has been improved when they received combined vitamin-mineral preparation "Duovit" for one month. Universal prophylactic vitaminization by means of administration of ascorbic acid and polyvitamin preparations in doses corresponding to the daily physiological requirement should be recommended as the most reliable, effective and economical measure aimed to improve supply of the population with vitamins.
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PMID:[The vitamin and trace element status of the personnel of the Chernobyl Atomic Electric Power Station and of preschool children in the city of Slavutich]. 762 54

In the present study, we examined denervation-induced changes in the sensitivity of hypothalamic postsynaptic serotonin1A (5-HT1A) receptor function with respect to changes in the dose-dependent elevation in plasma hormones [adrenocorticotropic hormone (ACTH), corticosterone, prolactin, oxytocin, prolactin, renin and vasopressin] by the 5-HT1A agonist 8-hydroxy-2-(dipropylamino)tetralin (8-OH-DPAT). Rats received intracerebroventricular (i.c.v.) injections of the serotonin neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) or vehicle (0.1% ascorbate in saline) 3 weeks before challenge with increasing doses of 8-OH-DPAT (0, 10, 50 or 200 micrograms/kg s.c.). The effectiveness of 5,7-DHT-induced destruction of serotonergic neurons was confirmed by a 93% reduction in [3H]paroxetine-labeled 5-HT uptake sites in the hypothalamus. No changes in basal levels of ACTH, corticosterone, oxytocin, prolactin, renin and vasopressin were observed in rats that received i.c.v. 5,7-DHT injections. The dose-response curves for 8-OH-DPAT-induced elevations of plasma corticosterone and prolactin levels were shifted to the left in rats treated with 5,7-DHT, whereas no significant difference in the ACTH dose-response curve was observed between rats treated with vehicle and rats treated with 5,7-DHT. In contrast, the maximal oxytocin response to 8-OH-DPAT was attenuated in rats treated with 5,7-DHT. A 5,7-DHT-induced decline in the synthesis of oxytocin could explain this phenomenon. Although 8-OH-DPAT did not increase plasma levels of renin or vasopressin in rats treated with vehicle, 8-OH-DPAT produced an elevation (75%) in plasma renin concentration but not in vasopressin levels in rats that received i.c.v. injections of 5,7-DHT. No change was observed in [3H]8-OH-DPAT labeled 5-HT1A receptors in the hypothalamus. In summary, denervation of hypothalamic serotonergic nerve terminals produces supersensitivity of some neuroendocrine responses to 8-OH-DPAT independent of changes in the density of hypothalamic 5-HT1A receptors.
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PMID:Alterations in 8-hydroxy-2-(dipropylamino)tetralin-induced neuroendocrine responses after 5,7-dihydroxytryptamine-induced denervation of serotonergic neurons. 965 67

This study was conducted to determine the effects of vitamin C (L-ascorbic acid) and vitamin E (alpha-tocopherol acetate) on serum concentrations of lipid peroxidation (MDA) and triiodothyronine (T3), thyroxine (T4), adrenocorticotropic hormone (ACTH), and some metabolite and mineral in laying hens reared at high ambient temperatures ranging from 25 degrees C to 35 degrees C. One hundred twenty laying hens (18 wk old; Hy-Line) were divided into 4 groups, 30 hens per group. The laying hens were fed either a basal diet (control) or the basal diet supplemented with either 250 mg of L-ascorbic acid/kg of diet (vitamin C), 250 mg of alpha-tocopherol acetate/kg of diet (vitamin E), or 250 mg of L-ascorbic acid plus 250 mg alpha-tocopherol acetate/kg of diet (combination). Separately or as a combination vitamins C and E increased serum vitamin C and vitamin E concentrations (p < 0.001) but decreased serum MDA concentration (p < 0.05). Serum concentrations of vitamin E and vitamin C were found highest but serum MDA concentration was lowest in the combination group. Supplemental vitamins C and E either separately or in a combination increased serum T3 and T4 concentrations (p < 0.05), whereas decreased serum ACTH concentration (p < 0.01). Serum glucose and cholesterol concentrations decreased, whereas serum protein concentration increased (p < 0.05) when vitamins C and E singly or together were added to the diet. Vitamin C and vitamin E supplementation resulted in an increase in serum concentrations of Ca, P, and K (p < 0.01) but a decrease in serum concentration of Na (p < 0.05). The results of the present study suggest that supplemental vitamin C and vitamin E alter serum lipid peroxidation, vitamin C, vitamin E and metabolite status, and diets supplemented with a combination of these two vitamins offer a good management practice in laying hens reared at high temperatures. In addition, the results suggest that dietary vitamin C and vitamin E act synergistically.
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PMID:Effects of vitamin C and vitamin E on lipid peroxidation, blood serum metabolites, and mineral concentrations of laying hens reared at high ambient temperature. 1188 97


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