Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Effects of triiodothyronine treatment on (Na+,K+)-ATPase in the brain, liver, kidney, and skeletal muscle were studied in the rat. The number of (Na+,K+)-ATPase units in the particulate fractions obtained from deoxycholate-treated homogenates was estimated from the concentration of [3H]ouabain binding sites assayed with a labeled drug-displacement method. The concentration of [3H]ouabain binding sites was highest in the brain tissue, intermediate in the kidney, and relatively low in the liver and skeletal muscle. The affinity of the binding sites for ouabain was highest in the brain, intermediate in the skeletal muscle, low in the kidney, and lowest in the liver. Triiodothyronine treatment increased the [3H]ouabain binding site concentration in the liver, kidney, and skeletal muscle but failed to affect it in the brain. Affinity of the binding sites for ouabain was unchanged by the triiodothyronine treatment in all tissues studied. These data indicate that triiodothyronine treatment of rats results in an increased tissue concentration of (Na+,K+)-ATPase in the liver, kidney, and skeletal muscle, but not in the brain. These changes do not accompany marked changes in the characteristics of the enzyme.
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PMID:Increased (Na+,K+)-ATPase concentrations in various tissues of rats caused by thyroid hormone treatment. 14 37

In vitro thyroxine inhibited accumulation of Ca2+ by fragments of sarcoplasmic reticulum, isolated from rabbit sceletal muscles. The inhibitory effect of thyroxine was responsible for its direct action on Ca2+ dependent ATPase. Half-maximal inhibition of the enzymatic activity occurred at the same concentrations of thyroxine using both membrane-bound and highly purified solubilized forms of Ca2+-ATPase (15--20 micrometer and 10 micrometer of the hormone, respectively). Triiodothyronine was similar in the effect but not diiodothyrosine, which did not possess the hormonal activity. The data obtained suggest that thyroid hormones affect the mechanism of dephosphorylation in ATP-hydrolase reaction.
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PMID:[Effect of thyroid hormones on the calcium pump in sarcoplasmic reticulum]. 15 72

To assess the possible role of the Na+ pump in mediating physiological responses to thyroid hormone in the rat myocardium, we examined the effects of L-3,5,3'-triiodothyronine (T3) on the activities of the closely associated enzymes, Na+-K+-dependent adenosine triphosphatase (Na-K-ATPase) and K+-dependent p-nitrophenyl phosphatase (K-dep-pNPPase). In hypothyroid rats, administration of T3 (50 microng/100 g body wt) resulted in significant increases (greater than 50%) in Na-K-ATPase and K-dep-pNPPase activities in both crude homogenates and microsomal fractions of the rat ventricle. Significant effects on Na-K-ATPase activity were also attained with low doses (1 microng/100 g body wt) of T3. A method was developed for assaying K-dep-pNPPase activity in cardiac slices. With this technique, enhancement in K-dep-pNPPase activity of 89.2% was found in ventricle slices after treatment of hypothyroid rats with T3 (50 microng/100 g body wt), implying that augmentation of the capacity of the Na+ pump is achieved in vivo. The potent analogue, L-3,5-diiodo-3' isopropyl thyronine (isopropyl T2) had the same effects on cardiac growth and Na-K-ATPase as T3, in hypothyroid rats. In contrast, the relatively inactive isomer, L-3,3',5'-triiodothyronine (reverse T3) had no significant effect on the heart weight-to-body weight ratio or on ventricular Na-K-ATPase activity.
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PMID:Thyroid hormone control of Na+-K+-ATPase and K+-dependent phosphatase in rat heart. 19 6

In gastrocnemius muscle from newborn rats the mRNA for the fast sarcoplasmic reticulum (SR) Ca(2+)-ATPase isoform (SERCA1) comprised over 90% of total SR Ca(2+)-ATPase mRNA content and increased 5-fold between day 5 and 20 after birth, whereas in hypothyroid muscle the SERCA1 message level remained constant. Triiodothyronine (T3) treatment of 2-day-old euthyroid rats induced a precocious stimulation of SERCA1 mRNA levels, indicating that T3 is the determining factor in the stimulation of SERCA1 message levels and that this stimulation underlies the previously reported effect of the thyroid status on the neonatal development of SR Ca(2+)-ATPase activity. The low mRNA level for the slow SR Ca(2+)-ATPase isoform (SERCA2) was constant in both euthyroid and hypothyroid muscle development. Nevertheless, T3 treatment of hypothyroid neonates induced a transient stimulation of SERCA2 message levels, indicating that SERCA2 is responsive to higher levels of T3.
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PMID:Thyroid hormone regulates Ca(2+)-ATPase mRNA levels of sarcoplasmic reticulum during neonatal development of fast skeletal muscle. 130 93

Indian River male broiler chickens growing from 7 to 28 d of age were fed on diets containing energy:protein values varying from 43 to 106 MJ/kg protein and containing 0 or 1 mg triiodothyronine (T3)/kg diet to study effects on growth, metabolic hormone concentrations and in vitro lipogenesis. In vitro lipid synthesis was determined in liver explants in the presence and absence of ouabain (Na+, K(+)-transporting ATPase (EC 3.6.1.37) inhibitor) to estimate the role of enzyme activity in explants synthesizing lipid. Growth and feed consumption increased (P < 0.01) when the energy:protein value decreased from 106 to 71 MJ/kg protein; however, both variables decreased as the value was further decreased from 53 to 43 MJ/kg protein. Triiodothyronine depressed (P < 0.01) growth, but not food intake. Large energy:protein diets (> 53 MJ/kg protein) and dietary T3 lowered (P < 0.01) plasma growth hormone. Large energy:protein diets (> 53 MJ/kg protein) increased (P < 0.01) lipogenesis, plasma growth hormone (GH) and decreased plasma insulin-like growth factor 1 (IGF-1). Also, T3 decreased plasma GH, IGF-1 in vitro lipogenesis. Ouabain inhibited a greater proportion of in vitro lipogenesis in those explants synthesizing fat at a high rate. Both dietary T3 and in vitro ouabain decrease lipogenesis, but, when combined, the effects are not cumulative.
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PMID:In vitro lipid metabolism, growth and metabolic hormone concentrations in hyperthyroid chickens. 133 68

The Na,K-ATPase alpha isoform (alpha 1, alpha 2, and alpha 3) and beta subunit genes exhibit a complex pattern of expression during heart development. To identify possible molecular signals that regulate the differential expression of these genes, isolated neonatal rat myocardial and non-myocardial cells were cultured in chemically defined medium and the responses of the multiple Na,K-ATPase subunit mRNAs to various hormones were tested. Myocardiocytes in control cultures express primarily alpha 1 and beta mRNAs. Triiodothyronine (T3) induced the expression of alpha 2, alpha 3, and beta mRNAs without influencing alpha 1 mRNA levels. Dexamethasone (DEX) treatment similarly induced alpha 2 mRNA levels, but the abundance of the other subunit transcripts remained unaltered. T3 and DEX together caused increases in alpha 2 and beta mRNA, increments similar to that observed with T3 alone. However, DEX specifically repressed the induction of alpha 3 mRNA by T3. Both hormones stimulated corresponding changes in the sarcolemma concentration of these Na,K-ATPase isozymes. Addition of norepinephrine to the cultures had little appreciable effect on expression of the alpha isoform and beta mRNAs. Although characterized less extensively, control cultures of non-myocardiocytes expressed alpha 1, alpha 3, and beta mRNAs, of which only the beta mRNA was stimulated by T3. These data indicate that thyroid and glucocorticoid hormones differentially regulate the expression of multiple alpha isoform and beta subunit mRNAs of Na,K-ATPase in cardiocytes in vitro and, therefore, may also be important physiological modulators in vivo.
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PMID:Thyroid and glucocorticoid hormones regulate the expression of multiple Na,K-ATPase genes in cultured neonatal rat cardiac myocytes. 168 3

The expression of mRNAs encoding the alpha- and beta-subunits of Na(+)-K(+)-ATPase (Na(+)-K+ pump) was examined in a rat liver cell line, Clone 9, in various thyroidal states. Northern blot analysis of total RNA isolated from cells incubated in hypothyroid serum-containing medium revealed the expression of mRNAs encoding Na(+)-K(+)-ATPase alpha 1-(mRNA alpha 1) and beta- (mRNA beta) subunits; mRNAs encoding the alpha 2- and alpha 3-subunits were undetectable. There was a discrepancy in the abundance of mRNA alpha 1 relative to mRNA beta such that mRNA alpha 1 exceeded the sum of the multiple mRNA beta bands by approximately 35-fold. 3,3',5-Triiodothyronine (T3) produced a coordinate augmentation of mRNA alpha 1 and mRNA beta contents that was demonstrable within 2 h and preceded the stimulation of Na(+)-K(+)-ATPase activity. After incubation of cells with T3 for 48 h, Na(+)-K(+)-ATPase activity was stimulated by 1.32-fold, whereas mRNA alpha 1 and mRNA beta abundances were increased 1.46- and 2.87-fold, respectively. Treatment of cells for 6 h with 10 micrograms/ml cycloheximide, a concentration sufficient to inhibit protein synthesis by 95%, elicited a 3.5- and 5.1-fold increase in mRNA alpha 1 and mRNA beta content, respectively. Cycloheximide abrogated the stimulatory effect of T3 on mRNA beta abundance, whereas the T3-induced increase in mRNA alpha 1 content was not prevented.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thyroid hormone induction of Na(+)-K(+)-ATPase and its mRNAs in a rat liver cell line. 215 38

Differences in immunological abnormalities like autoimmunity, abnormal T cell proliferative disorders and accelerated ageing occur between MRL/Mp-lpr/lpr(lpr/lpr) and MRL/Mp-+/+(+/+) mice as a consequence of one gene. The present study was designed to assess the effect of these differences in genotype and diet on the composition and function of the liver nuclear envelope. Mice of both strains were fed nutritionally adequate diets differing only in fatty acid composition for 4 weeks. Phospholipid fatty acid composition of the liver nuclear envelope was determined and the effect of altering the lipid composition of the nuclear membrane on nucleoside-triphosphatase (NTPase) activity, ribonucleic acid (RNA) efflux and binding of L-triiodothyronine (L-T3) was determined. Strain of mouse and level of dietary linoleic acid exhibited significant effects on the phospholipid fatty acid composition of the nuclear envelope. Levels of 18:1(n - 9) and 18:2(n - 6) were lower and 20:4(n - 6) content was higher in nuclear envelope phospholipids of lpr/lpr mice compared with mice of the +/+ strain. Mice fed the high linoleic acid diet exhibited higher levels of 18:0, 18:2(n - 6) and 20:4(n - 6) and lower levels of 16:0 and 18:1(n - 9) in liver nuclear envelope phospholipids, compared with mice fed the low linoleic acid diet. These changes in membrane composition were reflected in alteration of NTPase activity and efflux of RNA from isolated mouse liver nuclei. Nucleoside triphosphatase activity and efflux of ribonucleic acid from isolated nuclei were significantly higher in livers of the lpr/lpr strain. NTPase activity and RNA efflux from isolated nuclei were higher in the high linoleic acid fed group compared with the low linoleic acid group. A single class of binding sites for L-T3 was present in liver nuclear envelopes of these mice and Kd values were not influenced by strain or dietary linoleic acid levels. Nuclear envelopes prepared from +/+ animals exhibited a significantly higher number of binding sites for L-T3 compared with the lpr/lpr group. These observations indicate that the single gene difference characterizing lpr/lpr mice from +/+ mice results in alterations in the composition and function of the nuclear envelope. This genetic difference also alters the response of this membrane to dietary factors known to modulate characteristics and functions of the nuclear envelope.
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PMID:Ribonucleic acid efflux from isolated mouse liver nuclei is altered by diet and genotypically determined change in nuclear envelope composition. 245 56

In vivo administration of L-thyroxine (L-T4) in Anabas testudineus, while significantly stimulated the activities of cytochrome c oxidase and alpha-glycerophosphate dehydrogenase (alpha-GPDH), inhibited glucose-6-phosphate dehydrogenase (G-6-PDH), cytosolic and mitochondrial malate dehydrogenase (cyt. MDH; mit. MDH), and Mg2+ DNP-dependent adenosine triphosphatase (Mg2+ ATPase) activities. The activities of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), and catalase remained unaltered after L-T4 treatment. Administration of protein synthesis inhibitors such as actinomycin D, while significantly inhibited cytochrome oxidase, alpha-GPDH, catalase, SDH, and Mg2+ ATPase activities, did not change LDH, cyt. MDH, and mit. MDH activities. Chloramphenicol injection significantly stimulated cytochrome oxidase, alpha-GPDH, and G-6-PDH activities. Simultaneous injections of actinomycin D or chloramphenicol with 3,5,3'-triiodo-L-thyronine (L-T3) or L-T4 prevented the effects of thyroid hormones on enzyme activities, when compared to the respective controls.
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PMID:Oxidative metabolism in a teleost, Anabas testudineus Bloch: effect of thyroid hormones on hepatic enzyme activities. 292 Sep 3

In the urodelan amphibian Pleurodeles waltlii, spontaneous anatomical metamorphosis was correlated with an increase in the serum level of thyroxine (T4). It was also accompanied by a change in the myofibrillar ATPase profile of the dorsal skeletal muscle; fibers of larval type were gradually replaced by the adult fiber types I, II A, and II B. Likewise, a myosin isoenzymic transition was observed in dorsal muscle, larval isomyosins were replaced by adult isoforms. In a related species, Ambystoma mexicanum, in which no spontaneous external metamorphosis occurs under standard conditions, the serum T4 level was shown to remain low. During further development, the myofibrillar ATPase profile acquired the adult fiber types, but a high percentage of immature fibers of type II C persisted. Myosin isoenzymic transition was also incomplete; larval isoforms were still distinguished in the neotenic adults. In experimental hypothyroidian P. waltlii, no external metamorphosis occurred; the myofibrillar ATPase profile was of the immature type, and the larval isomyosins persisted. Triiodothyronine induced experimental anatomical metamorphosis in A. mexicanum; only limited changes in the myofibrillar ATPase profile resulted from the treatment, but a complete myosin isoenzymic transition was observed. These results tend to indicate that a moderate increase in the level of thyroid hormone is sufficient to induce the differentiation of adult fiber types, together with the production of adult myosin isoforms in the skeletal dorsal muscle of amphibians, while a pronounced increase would be necessary for repressing the initial larval features.
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PMID:Regulation by thyroid hormones of terminal differentiation in the skeletal dorsal muscle. II. Urodelan amphibians. 295 62


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