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)

Sertoli cell-enriched preparations were obtained by sequential enzyme treatment of testes of 18-20 day old rats, and were maintained in culture in a chemically defined medium. The addition of highly purified follicle-stimulating hormone (FSH) to cells immediately after preparation, or after 48 h in culture, elicited an increase in the level of cyclic adenosine 3',5'-monophosphate (cAMP) when incubated in the presence of 3-isobutyl-1-methylxanthine (MIX). Luteinizing hormone (LH) had no effect on the cAMP levels. The cells cultured in the presence of FSH or dibutyryl cAMP for 48 h incorporated more [3H]leucine into trichloroacetic acid (TCA)-insoluble material than did cells cultured in the basal medium. Cycloheximide abolished the amino acid incorporation into protein precipitated by TCA. The data demonstrate that the Sertoli cell is a target cell for FSH action, and indicate that added dibutyryl cAMP can duplicate the enhancement of amino acid incorporation into protein elicited by FSH.
Mol Cell Endocrinol 1975 Jul
PMID:Effects of follicle-stimulating hormone on cultures of Sertoli cell preparations. 16 4

Corticosterone production by isolated rat adrenal cells in the absence of ACTH is stimulated by 20alpha-hydroxycholesterol, 22R-hydroxycholesterol and 25-hydroxycholesterol. This effect is also seen at sub-maximal ACTH concentrations. Aminoglutethimide (AGI) inhibits the stimulation caused by the three hydroxylated cholesterols. In the presence of ACTH, AGI also inhibits steroid production both under control conditions and in the presence of the sterols. The stimulation by 25-hydroxycholesterol is dose-dependent, both in the presence and absence of a sub-maximal ACTH concentration. At maximal ACTH concentrations 25-hydroxycholesterol does not give additional stimulation. Cycloheximide has no effect on corticosterone production from 25-hydroxycholesterol whether ACTH is present or not. Our results indicate that 25-hydroxycholesterol is a good substrate for the study of the cholesterol side-chain cleaving system and the mechanism of action of ACTH at the levels of the intact cell.
Mol Cell Endocrinol 1975 Nov
PMID:Studies on isolated rat adrenal cells metabolism of hydroxylated sterols. 17 94

Cycloheximide and chloramphenicol both inhibit the stimulating effect of adenocorticotropic hormone (ACTH) on adrenal steroid production. To test whether these inhibitors had andy effect on adrenal steroid production, independent fromthe mechanism of action of ACTH we investigated their effect on the conversion of 25-hydroxycholesterol into corticosterone in isolated rat adrenal cells. Cycloheximide, both in the absence and in the presence of ACTH, had no effect on this conversion. Chloramphenicol inhibited the conversion of 25-hydroxycholesterol into corticosterone whether ACTH has no direct efeect on the cholesterol side-chain cleaving system. The inhibition by chloramphenicol of the ACTH-stimulated steroid production is at least partly due to inhibition of one or more of the processes involved in the conversion of 25-hydroxycholesterol into corticosterone.
Mol Cell Endocrinol 1976 May
PMID:Different effects of cycloheximide and chloramphenicol on corticosterone production by isolated rat adrenal cells. 18 Dec 83

Adult male rats were injected subcutaneously with a mixture of hCG and [125I]hCG (3, 5, 10, 100 or 1000 IU), and killed 3, 6, 16, 24 or 48 h after injection. Specific uptake of [125I]hCG by the testes as well as the remaining in vitro binding capacity were measured. Cycloheximide (1.5 mg/kg) was given together with hCG to another group of animals. The effect of hCG on testicular LH/hCG receptors was found to consist of two phases: first, 6--16 h after injection, a significant increase in the binding capacity occurred, which was found with the lower 3--10 IU doses of hCG. Thereafter there was a pronounced decrease in receptor concentration, which was directly correlated to the dose of hCG. Experiments with cycloheximide suggest that the decrease in binding, but not the increase, is at least partly dependent on protein synthesis.
Mol Cell Endocrinol 1978 Jun
PMID:HCG-induced changes in the number of rat testis LH/HCG receptors. 21 59

With puromycin one can recognize when the synthesis of a given protein is dependent on amino acyl tRNA that is present in rate limiting amount. We demonstrate this use of puromycin by its interaction with another inhibitor, L-o-methylthreonine. L-o-methylthreonine lowers the Ile-tRNA concentration in the cell, thereby inhibiting synthesis of proteins containing isoleucine. In certain rabbits, the alpha hemoglobin chain has three isoleucyl residues and the beta chain none. L-o-methylthreonine thus inhibits alpha globin synthesis in intact reticulocytes from these rabbits. When puromycin and L-o-methylthreonine are used together, the two inhibitors synergize in inhibiting alpha globin synthesis. Hence, puromycin is a more effective inhibitor when the Ile-tRNA concentration is lowered. Cycloheximide and sodium fluoride have different modes of action from puromycin. Neither synergizes with L-o-methylthreonine; instead, the interaction is less than additive. We have found that beta chain synthesis in rabbit reticulocytes is more sensitive than alpha to inhibition by puromycin. This difference could reflect either differences in amino acid sequence or tRNA dependent limitations of beta chain elongation. The switch from fetal to adult hemoglobin in humans does not involve changes in limiting amino acyl tRNA because, for cord blood from infants of different developmental ages, the puromycin sensitivity of incorporation into gamma and beta chains remains constant.
Mol Cell Biochem 1978 Feb 24
PMID:Testing with puromycin and amino acyl tRNAs that limit the rate of peptide chain extension. 24 96

Treatment of rat thymus cells with the glucocorticoids cortisol and dexamethasone resulted in the stimulation of RNA polymerase B activity within 10 min of steroid addition. This early effect was followed by the inhibition of both RNA polymerase A and B activities. These effects were glucocorticoid-specific and were inhibited by the antiglucocorticoid cortexolone. The inhibitory effect of dexamethasone on RNA polymerase A activity was abolished by prior treatment of the cells with alpha-amanitin, cordycepin or cycloheximide, but cycloheximide was only capable of inhibiting the steroid effect measured at 3 h if added within 10--20 min after steroid addition. Cycloheximide had no effect on the steroid-mediated inhibition of RNA polymerase B activity. Control RNA polymerase A activities were unaffected by the presence of inhibitors of RNA and protein synthesis. It is concluded that the inhibition of ribosomal RNA synthesis by glucocorticoids is dependent on protein synthesis, but that basal RNA polymerase A activity in rat thymus cells is not stringently coupled to protein synthesis.
Mol Cell Endocrinol 1978 Jan
PMID:Glucocorticoid regulation of rat thymus RNA polymerase activity: the role of RNA and protein synthesis. 30 18

The incorporation of labeled amino acids and glucosamine into LH and FSH by cultured rat anterior pituitary cells and anterior pituitary homogenates is reported. There was a significant augmentation in this incorporation by cells after 6 days of culture in the presence of GnRH. Tritiated LH and FSH were found in the cell extracts as well as in the media by the method of immunoprecipitation. An increase of approximately 7--13-fold in the release of LH and FSH into the cell incubation medium was observed in the presence of GnRH (3 ng/ml). The rate of incorporation of [3H]proline was higher than that of [3H]glucosamine into LH and FSH. At the same time a higher incorporation of labeled amino acids was observed in the case of FSH than with LH. Cycloheximide inhibited completely the incorporation of labeled proline but the inhibition was partial for the incorporation of labeled glucosamine. Freshly dispersed cells, short-time cultures maintained for 20 h and pituitary homogenates also incorporated labeled amino acids into LH and FSH, but GnRH had no effect on this incorporation. Pituitary homogenates also incorporated [3H]glucosamine into LH and FSH with an optimal incorporation after 30 min of incubation. Three different concentrations of GnRH had no effect on the incorporation of [3H]proline by homogenates. Cycloheximide and puromycin inhibited this incorporation completely.
Mol Cell Endocrinol 1978 Oct
PMID:Biosynthesis of gonadotropins by rat pituitary cells in culture and in pituitary homogenates: effect of gonadotropin-releasing hormone. 36 88

Studies were undertaken to determine if mitochondrial rRNA synthesis in yeast is regulated by general cellular stringent control mechanism. Those variables affecting the relaxation of a cycloheximide-induced stringent response as a result of medium-shift-down or tyrosine limitation include: 1) the stage of cell growth, 2) carbon source, 3) strain differences and, 4) integrity of the cell wall. The extent of phenotypic relaxation decreased or was eliminated entirely in a strain dependent manner as cells entered stationary phase of growth or by growth of cells on galactose or in osmotically stabilized spheroplast cultures. Cytoplasmic and mitochondrial RNA species were extracted from regrowing spheroplast cultures subjected to different experimental regimens and analyzed by electrophoresis on 2.5% polyacrylamide gels. Relative rates of synthesis were determined in pulse experiments and normalized by double-label procedures to longterm label material. Tyrosine starvation was found to inhibit synthesis of the large and small rRNA species of both cytoplasmic and mitochondrial rRNAs to about 5-20% of the control values. Chloramphenicol inhibits mitochondrial and cytoplasmic rRNA synthesis to 60-80% of control; however, chloramphenicol addition does not relax the stringent inhibition of either class of rRNAs. Cycloheximide addition results in 70-80% inhibition of synthesis of both cellular speceis of rRNAs. As noted above, cycloheximide does not relax the stringent response of cytoplasmic rRNA synthesis in spheroplasts, and also does not relax the stringent inhibition of mitochondrial rRNA synthesis. From these studies, we conclude that both cytoplasmic and mitochondrial rRNA synthesis share common control mechanisms related to regulation of protein synthesis by shift-down or amino acid limitation.
Mol Gen Genet 1979 Jun 20
PMID:Regulation of mitochondrial ribosomal RNA synthesis in yeast. I. In search of a relaxation of stringency. 38 47

With the use of neutral sucrose sedimentation techniques, the size of unirradiated nuclear DNA and the repair of double-strand breaks induced in it by ionizing radiation have been determined in both wild-type and homozygous rad52 diploids of the yeast Saccharomyces cerevisiae. The number average molecular weight of unirradiated DNA in these experiments is 3.0 X 10(8)+/-0.3 Daltons. Double-strand breaks are induced with a frequency of 0.58 X 10(-10) per Daltonkrad in the range of 25 to 100 krad. Since repair at low doses is observed in wild-type but not homozygous rad52 strains, the corresponding rad52 gene product is concluded to have a role in the repair process. Cycloheximide was also observed to inhibit repair to a limited extent indicating a requirement for protein synthesis. Based on the sensitivity of various mutants and the induction frequency of double-strand breaks, it is concluded that there are 1 to 2 double-strand breaks per lethal event in diploid cells incapable of repairing these breaks.
Mol Gen Genet 1976 Jan 16
PMID:The repair of double-strand breaks in the nuclear DNA of Saccharomyces cerevisiae and its genetic control. 76 49

Cycloheximide (5.0 mug/ml) had no significant effect on respiration of liver slices prepared from euthyroid rats (i.e., QO2 of 15.5 +/- 0.8 vs. 14.9 +/- 0.8 mul/mg protein) despite an 83.8 +/- 2.1% inhibition of protein synthesis as judged by [3H]leucine incorporation into the trichloroacetic acid precipitable fraction. Injection of triiodothyronine increased the QO2 of rat liver slices to 22.6 +/- 1.1 mul/h/mg protein. The QO2 of hyperthyroid slices remained high in the presence of cycloheximide although protein synthesis was inhibited by 84.4 +/- 2.0%. These results imply that the energy requirement for protein synthesis contributes little to QO2 of euthyroid liver and does not account for a significant fraction of the increase in hepatic QO2 obtained in the transition from the euthyroid to the hyperthyroid state.
Mol Cell Endocrinol
PMID:Thyroid thermogenesis: minimal contribution of energy requirement for protein synthesis. 95 45


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