Influence of aortic coarctation on myocardial glucose-6-phosphate dehydrogenase

1969 ◽  
Vol 47 (4) ◽  
pp. 388-391 ◽  
Author(s):  
J. R. E. Valadares ◽  
R. L. Singhal ◽  
M. R. Parulekar ◽  
Margaret Beznak
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Cardiac Hypertrophy ◽  
Aortic Coarctation ◽  
Significant Inhibition ◽  
Rna And Protein Synthesis ◽  
Wet Weight ◽  
Glucose 6 Phosphate Dehydrogenase

Alterations in the activity of myocardial glucose-6-phosphate dehydrogenase were studied in rats with experimentally produced cardiac hypertrophy. Six days after aortic coarctation, enzyme activity was increased to more than 200% of the control values when expressed either per gram wet weight or per organ. Administration of cycloheximide resulted in a significant inhibition of the increase in cardiac glucose-6-phosphate dehydrogenase noted after constriction. It is conceivable that the augmentation in the activity of this enzyme may be related to the increases in RNA and protein synthesis observed during development of cardiac hypertrophy.

Paradoxical effect of perchlorate on thyroidal weight, glucose 6-phosphate dehydrogenase and polyamines in methylthiouracil-treated rats

1981 ◽  
Vol 97 (4) ◽  
pp. 491-495 ◽  
Author(s):  
S. Matsuzaki ◽  
M. Suzuki
Keyword(s):  
Enzyme Activity ◽  
Control Level ◽  
Sodium Perchlorate ◽  
Inhibitory Effect ◽  
Paradoxical Effect ◽  
G6pdh Activity ◽  
Wet Weight ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract. The effect of sodium perchlorate (NaClO4) on the methylthiouracil-induced increase in the activity of thyroid glucose 6-phosphate dehydrogenase (G6PDH), ornithine decarboxylase (ODC) and polyamine contents was studied in the rat. The G6PDH activity was increased nearly three-fold by methylthiouracil (MTU) but not by ClO4- at 7 days of treatment. Perchlorate lowered the MTU-induced enzyme activity to nearly the control level, without changing circulating thyrotrophin (TSH). The anion had no inhibitory effect on G6PDH activity in vitro. The possibility that an inhibitor specific for G6PDH was generated in ClO4- treated rat thyroids was excluded. The activity of ODC was greatly increased by both ClO4- and MTU, the increase being significant as early as on the second day of treatment. Perchlorate had no inhibitory effect on MTU-induced ODC activity in vivo but decreased total contents of spermidine and spermine in the thyroid, without affecting the concentration (nmoles/ g wet weight) of the polyamines. These results suggest that ClO4- acts directly on the thyroid to suppress specifically the stimulatory effect of TSH on G6PDH activity and possibly on polyamine accumulation.

scholarly journals Induction of N-acetylglucosamine kinase in yeast

1974 ◽  
Vol 141 (2) ◽  
pp. 593-595 ◽  
Author(s):  
A. Bhattacharya ◽  
M. Puri ◽  
A. Datta
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Candida Albicans ◽  
Enzyme Synthesis ◽  
Transcriptional Level ◽  
Protein Synthesis Inhibitors ◽  
Rna And Protein Synthesis ◽  
New Protein

The presence of N-acetylglucosamine is essential for the induced synthesis of N-acetylglucosamine kinase in Candida albicans. The enzyme synthesis stops and its concentration in the cells declines rapidly as soon as N-acetylglucosamine is removed from the medium. Experiments with RNA- and protein-synthesis inhibitors indicate that the appearance of new enzyme activity is dependent on concomitant new protein synthesis and the inducer operates at a transcriptional level.

scholarly journals Metabolic control mechanisms in mammalian systems. Hormonal regulation of phosphofructokinase in the rat prostate and seminal vesicles

1968 ◽  
Vol 110 (4) ◽  
pp. 703-711 ◽  
Author(s):  
Radhey L. Singhal ◽  
J. R. E. Valadares
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Hormonal Regulation ◽  
Messenger Rna ◽  
Time Course ◽  
Seminal Vesicles ◽  
Minimal Amount ◽  
Simultaneous Administration ◽  
Rna And Protein Synthesis ◽  
Phosphofructokinase Activity

1. The hormonal regulation of phosphofructokinase was investigated in the accessory reproductive organs of the orchidectomized rat. 2. Phosphofructokinase activities declined to 51% and 47% in the prostate and 9% and 6% of the normal values in seminal vesicles 4 and 8 weeks after castration respectively. Administration of testosterone (100μg./100g. body wt.) for 3 days reversed substantially the effects of orchidectomy, and phosphofructokinase activity increased to 173% in the prostate and 536% in seminal vesicles as compared with the values of castrated controls. 3. Time-course studies demonstrated that after a single injection of testosterone (5mg./100g. body wt.) phosphofructokinase activity was maximally elevated to 236% in the prostate and 342% in seminal vesicles at 24hr. 4. Dose–response studies revealed that 2·5mg. of testosterone propionate/100g. body wt. was the minimal amount necessary to induce significant increases in enzyme activity in both accessory sex organs; maximal increases were obtained with a dose of 5mg./100g. body wt. 5. The observed enzyme increases induced by testosterone were inhibited by the simultaneous administration of oestradiol-17β, and phosphofructokinase activity in this group of rats remained at 97% in the prostate and 137% of the control values in seminal vesicles. Oestradiol-17β by itself failed to produce any significant effect on enzyme activity in either of these secondary sexual tissues. 6. The nature of the testosterone-induced increases in phosphofructokinase activity was studied by using a variety of inhibitors of RNA and protein synthesis. Cycloheximide, 5-fluorouracil and ethionine largely blocked the androgen-stimulated rise in enzyme activity observed 24hr. after steroid injection. The inhibitory effect of ethionine was completely reversed by the simultaneous administration of methionine. 7. Actinomycin, which is known to inhibit the synthesis of messenger RNA as well as the synthesis of other cellular RNA fractions, when given simultaneously with the hormone, also inhibited the testosterone-induced increases in prostatic and seminal-vesicular phosphofructokinase. However, when the antibiotic was given 6 or 12hr. after injection of the steroid, practically no inhibition of phosphofructokinase induction was obtained. This indicates that, once the enzyme-forming machinery is turned on and allowed to operate for a few hours, actinomycin is incapable of reversing the hormone-induced enzyme responses. 8. The results presented suggest that new RNA and protein synthesis may be involved in the observed androgen-induced increases in phosphofructokinase activity in the prostate and seminal vesicles of the orchidectomized rat.

scholarly journals Nucleic acid and protein synthesis associated with the induction of nitrate reductase activity in radish cotyledons

1968 ◽  
Vol 108 (5) ◽  
pp. 715-724 ◽  
Author(s):  
J. Ingle
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Control System ◽  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Reductase Activity ◽  
Radioactive Precursor ◽  
Rna And Protein Synthesis

1. RNA and protein synthesis was studied during the incubation of excised radish cotyledons in nitrate, conditions that induced nitrate reductase activity in the tissue. 2. Synthesis of total RNA and protein, as measured by the incorporation of radioactive precursor, was significantly stimulated in the presence of nitrate (compared with chloride control), but was decreased in the presence of ammonium nitrate, which induced higher enzyme activity. 3. Synthesis of RNA and protein was required for induction of enzyme activity, as determined by using the inhibitors actinomycin D, puromycin and cycloheximide. 4. On the basis of 5-fluorouracil inhibition, the synthesis of only DNA-like RNA was required for induction, but no differences, either quantitative or qualitative, were observed in DNA-like RNA synthesis in the presence or absence of induction. 5. A 100-fold purification of the nitrate reductase activity showed no increase in nitrate reductase protein, nor any increased incorporation of radioactive precursor into nitrate reductase protein in the induced versus the control system. Such results suggested that the protein synthesis required for induction may be for a protein other than nitrate reductase.

FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1972 ◽  
Vol 70 (2) ◽  
pp. 396-408 ◽  
Author(s):  
K.-D. Schulz ◽  
H. Haarmann ◽  
A. Harland
Keyword(s):  
Protein Synthesis ◽  
Reproductive System ◽  
Rna Synthesis ◽  
Neonatal Period ◽  
High Dose ◽  
Female Reproductive System ◽  
Endocrine Control ◽  
Hypothalamic Region ◽  
Rna And Protein Synthesis ◽  
Physiological Dose

ABSTRACT The present investigation deals with the oestrogen-sensitivity of the female reproductive system during the neonatal period. Newborn female guinea pigs were used as test animals. At different times after a single subcutaneous injection of a physiological dose of 0.1 μg or an unphysiologically high dose of 10 μg 17β-oestradiol/100 g body weight, the RNA- and protein-synthesis was examined in the hypothalamic region, pituitary, cerebral cortex, liver, adrenal gland, ovary and uterus. With a physiological dose an increase in organ weight, protein content, RNA-and protein-synthesis was found only in the uterus. These alterations turned out to be dose-dependent. In addition to the findings in the uterus an inhibition of the aminoacid incorporation rate occurred in the liver following the injection of the high oestradiol dose. As early as 1 hour after the administration of 0.1 μg 17β-oestradiol an almost 100% increase in uterine protein synthesis was detectable. This result demonstrates a high oestrogen-sensitivity of this organ during the neonatal period. All the other organs of the female reproductive system such as the hypothalamus, pituitary and ovary did not show any oestrogen response. Therefore the functional immaturity of the uterus during post partem life is not the result of a deficient hormone sensitivity but is correlated with the absence of a sufficient hormonal stimulus at this time. The investigation on the effects of actinomycin resulted in different reactions in the uterus and liver. In contrast to the liver a paradoxical actinomycin effect was found in the uterus after treatment with actinomycin alone. This effect is characterized by a small inhibition of RNA-synthesis and a 50% increase in protein synthesis. The treatment of the newborn test animals with actinomycin and 17β-oestradiol together abolished the oestrogen-induced stimulation of the uterine RNA-and protein-synthesis. Consequently, the effect of oestrogens during the neonatal period is also connected with the formation of new proteins via an increased DNA-directed RNA-synthesis.

GPR39 promotes cardiac hypertrophy by regulating the AMPK‐mTOR pathway and protein synthesis

2021 ◽  
Author(s):  
Hongjuan Liao ◽  
Weinian Gao ◽  
Jie Ma ◽  
Hongyuan Xue ◽  
Yi Wang ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Cardiac Hypertrophy ◽  
Mtor Pathway

scholarly journals KLK11 promotes the activation of mTOR and protein synthesis to facilitate cardiac hypertrophy

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yi Wang ◽  
Hongjuan Liao ◽  
Yueheng Wang ◽  
Jinlin Zhou ◽  
Feng Wang ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Angiotensin Ii ◽  
Cardiac Hypertrophy ◽  
Western Blot ◽  
Real Time ◽  
Real Time Pcr ◽  
Mtor Signaling ◽  
Heart Weight ◽  
Cardiomyocyte Hypertrophy ◽  
Quantitative Real Time Pcr

Abstract Background Cardiovascular diseases have become the leading cause of death worldwide, and cardiac hypertrophy is the core mechanism underlying cardiac defect and heart failure. However, the underlying mechanisms of cardiac hypertrophy are not fully understood. Here we investigated the roles of Kallikrein 11 (KLK11) in cardiac hypertrophy. Methods Human and mouse hypertrophic heart tissues were used to determine the expression of KLK11 with quantitative real-time PCR and western blot. Mouse cardiac hypertrophy was induced by transverse aortic constriction (TAC), and cardiomyocyte hypertrophy was induced by angiotensin II. Cardiac function was analyzed by echocardiography. The signaling pathway was analyzed by western blot. Protein synthesis was monitored by the incorporation of [3H]-leucine. Gene expression was analyzed by quantitative real-time PCR. Results The mRNA and protein levels of KLK11 were upregulated in human hypertrophic hearts. We also induced cardiac hypertrophy in mice and observed the upregulation of KLK11 in hypertrophic hearts. Our in vitro experiments demonstrated that KLK11 overexpression promoted whereas KLK11 knockdown repressed cardiomyocytes hypertrophy induced by angiotensin II, as evidenced by cardiomyocyte size and the expression of hypertrophy-related fetal genes. Besides, we knocked down KLK11 expression in mouse hearts with adeno-associated virus 9. Knockdown of KLK11 in mouse hearts inhibited TAC-induced decline in fraction shortening and ejection fraction, reduced the increase in heart weight, cardiomyocyte size, and expression of hypertrophic fetal genes. We also observed that KLK11 promoted protein synthesis, the key feature of cardiomyocyte hypertrophy, by regulating the pivotal machines S6K1 and 4EBP1. Mechanism study demonstrated that KLK11 promoted the activation of AKT-mTOR signaling to promote S6K1 and 4EBP1 pathway and protein synthesis. Repression of mTOR with rapamycin blocked the effects of KLK11 on S6K1 and 4EBP1 as well as protein synthesis. Besides, rapamycin treatment blocked the roles of KLK11 in the regulation of cardiomyocyte hypertrophy. Conclusions Our findings demonstrated that KLK11 promoted cardiomyocyte hypertrophy by activating AKT-mTOR signaling to promote protein synthesis.

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