Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytochrome P450, aa3 and adrenodoxin were characterized in human adrenocortical mitochondria. Human adrenodoxin demonstrated a distinctive electron paramagnetic spectrum exhibiting anisotropic g values indicative of axial symmetry. The observed g values were (formula: see text). Adrenodoxin content of crude human adrenal mitochondria was 0.65 +/- 0.01 nmol/mg of mitochondrial protein and was in a stoichiometric 1:1 molar ration with cytochrome P450. Mitochondrial cytochrome P450 (0.62 nmol/mg mitochondrial protein) and aa3 (0.19 nmol/mg mitochondrial protein) levels were determined in a normal human adrenal A patient receiving ACTH (3d) demonstrated a doubling of P450 content, while cytochrome aa3 levels remained unchanged. ACTH plus hydrocortisone therapy (3d) increased both P450 and aa3 levels, however 24 h hydrocortisone therapy alone was without effect. An area of focal hyperplasia of the zona fasciculata also demonstrated P450 and aa3 levels elevated above the contralateral and normal human adrenal levels. The possibility of hormonal control of human adrenal mitochondrial cytochromes P450 and aa3 is suggested.
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PMID:Mitochondrial redox components of human adrenocortical steroid hydroxylases under physiological conditions and in focal hyperplasia of the zone fasciculata. 19 25

Concentration of corticosterene, activities of succinate dehydrogenase and cytochrome oxidase, contents of ascorbic acid, reduced glutathione, free amino acids, RNA and DNA were studied in rat and rabbit adrenal glands within 10 min, 5, 10 and 24 hrs after crushing of the soft tissues of posterior extremities under conditions of unaltered and stimulated by ACTH functioning of adrenal glands. Stable increase in the biochemical parameters studied, caused by the ACTH effect, occurred in adrenal glands under this pathology.
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PMID:[Biochemical changes in the adrenals and their function in mechanical trauma]. 22 68

Recently the pH gradient evoked by a K+ diffusion potential was shown to translocate a synthetic monobasic amphipathic hexapeptide across the bilayer of lipid vesicles (De Kroon, A.I.P.M., Vogt, B., Van 't Hof, R., De Kruijff, B. and De Gier, J. (1991) Biophys. J. 60, in press). Here this observation is extended by studying the effect of a membrane potential on a set of bioactive peptides. The panel of peptides comprises the toxin mastoparan X, a tryptophan-containing analogue of the presequence of the mitochondrial protein cytochrome oxidase subunit IV (preCoxIV(1-25)W18), and the regulatory peptides ACTH(1-24), alpha-MSH, ACTH(1-10), dynorphin A, bombesin, and LHRH. The interaction of these peptides with phospholipid vesicles has been measured using the intrinsic tryptophan residue as fluorescent probe. In the absence of a K+ diffusion potential only mastoparan X and the presequence show considerable binding to vesicles consisting of phosphatidylcholine (PC). In contrast, under these conditions all peptides display affinity for vesicles consisting of the acidic phospholipid cardiolipin (CL), the extent of which depends on the net positive charge of the peptide. Application of a K+ diffusion potential to large unilamellar vesicles (LUV) consisting of PC results in a time dependent tryptophan fluorescence increase for mastoparan X, which is accelerated upon incorporating increasing amounts of CL into the LUV. A similar fluorescence increase in response to a K+ diffusion potential was observed for the above model peptide. Yet the mechanism resulting in the fluorescence increase of mastoparan X is completely different from that of the hexapeptide. Binding experiments indicate that a membrane potential-induced enhanced binding of the peptide to the outer surface of the vesicles contributes to the fluorescence increase. PreCoxIV(1-25)W18, dynorphin A, and ACTH(1-24) show fluorescence responses upon applying a membrane potential that are consistent with that of mastoparan X, whereas the other peptides tested do not respond up to a LUV CL content of 50%. The results tentatively suggest that the membrane potential only affects a peptide when it has the ability to adopt a stable membrane bound conformation.
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PMID:The effect of a membrane potential on the interaction of mastoparan X, a mitochondrial presequence, and several regulatory peptides with phospholipid vesicles. 168 Mar 97

Differential screening of an adrenal cortex cDNA library for corticotropin (ACTH)-inducible genes led to the isolation of a group of cDNAs representing mitochondrial genes that encode subunits of cytochrome oxidase, ATPase, and NADH dehydrogenase. Northern blot analysis of RNA from cells stimulated by ACTH confirmed the induction of these genes by ACTH yet revealed major differences in the relative responses of the respective mRNAs. The levels of mRNAs for cytochrome oxidase subunit I and ATPase increased 2- to 4-fold and for NADH dehydrogenase subunit 3 increased 20-fold, whereas the levels of the mitochondrial 16S rRNA showed no change within 6 h of ACTH stimulation. These effects of ACTH on mitochondrial mRNA levels probably result from both activation of the H2 transcription unit that encodes mitochondrial mRNAs and alteration of mRNA stability. ACTH also increased the activity of cytochrome oxidase after 12 h of stimulation. Examination of the tissue specificity of expression of five mitochondrial genes showed a wide range of RNA levels among 11 tissues but high correlations between individual RNA levels, consistent with a coordinated expression of the mitochondrial genes, although at different levels in each cell type. Proportionately high levels of mitochondrial mRNAs were found in adrenal cortex, probably reflecting a stimulatory effect of ACTH in vivo. Overall, the results indicate that ACTH enhances the energy-producing capacity of adrenocortical cells.
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PMID:Mitochondrial-genome-encoded RNAs: differential regulation by corticotropin in bovine adrenocortical cells. 750 67

An immunohistochemical study to demonstrate oncocytes in nongonadotrophic pituitary adenomas was performed. The adenomas were 10 prolactinomas, 2 ACTH-producing adenomas (ACTHomas), and 28 growth hormone-producing adenomas (GHomas); we also studied 5 pituitary oncocytomas. GHomas were divided into two groups: GHomas with (GHomas-1) and without (GHomas-2) fibrous bodies. A small number of solitary large cells showed intense cytoplasmic granular reactivity for mitochondrial protein and cytochrome oxidase, resembling oncocytes in oncocytomas. The proportions of the mitochondrial protein-positive cells ranged from zero to 2.1% (0. 3+/-0.4%). They were more frequent in GHomas, GHomas-1 in particular, than other types of adenomas (P<0.01), and were mostly negative in prolactinomas and ACTHomas. In multivariate analysis, the proportions showed positive correlation with age (P<0.01) and the Ki-67 (MIB-1) labeling index (P<0.01) and tended to increase in number with recurrence (P<0.05). In GHomas, these cells were more common in cases with low basal GH level (P<0.01) and large tumor volume (P<0.01). We consider that these cells represent oncocytes existing in varying numbers in adenomas. We suggest that oncocytic change in nongonadotrophic adenomas indicates poor differentiation and/or some aggressiveness, which lead to a decrease in the endocrine activity of the tumor.
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PMID:Immunohistochemical demonstration of oncocytes in nongonadotrophic pituitary adenomas. 1052 7