Reference

Hormonal regulation of translatable mRNA of tryptophan 2,3-dioxygenase in primary cultures of adult rat hepatocytes

Hormonal regulation of translatable mRNA of tryptophan 2,3-dioxygenase in primary cultures of adult rat hepatocytes. Niimi, Shingo; Nakamura, Toshikazu; Nawa, Katsuhiko; Ichihara, Akira (Sch. Med., Univ. Tokushima, Tokushima 770, Japan). J. Biochem. (Tokyo), 94(5), 1697-706 (English) 1983. CODEN: JOBIAO. ISSN: 0021-924X. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Tryptophan 2,3-dioxygenase (EC 1.13.11.11) [9014-51-1] in primary cultures of adult rat hepatocytes was induced 3-4 fold by 1 mM dexamethasone [50-02-2] and 6-7 fold by dexamethasone plus glucagon [9007-92-5] (0.1 mM). Changes of the enzyme activity, amt. of enzyme measured by immunotitration, and rate of enzyme synthesis assayed by measurement of [3H]leucine incorporation into the enzyme protein were closely correlated. Furthermore, in a reticulocyte lysate system for cell-free protein synthesis, mRNA of the enzyme was translated to the protein corresponding to the subunit of tryptophan 2,3-dioxygenase, which was identified by SDS-polyacrylamide gel electrophoresis. The activity of translatable mRNA of the enzyme was increased >10-fold by dexamethasone and its final content in total mRNA was 0.34%. Glucagon alone did not increase mRNA activity, but dexamethasone plus glucagon increased mRNA activity to twice that with dexamethasone alone; the maximal content of the mRNA being 0.77% of the total mRNA content 12 h after addn. of hormones. Insulin [9004-10-8] (0.1 mM) caused 75% inhibition of the max. increase of mRNA activity of the enzyme induced by dexamethasone and glucagon. 9004-10-8 and 9007-92-5 which are cas registry numbers of substances are two of reagents here. Epinephrine [51-43-4] (10 mM) also caused 58% inhibition of the max. increase. Insulin and epinephrine also suppressed increase of mRNA of tryptophan 2,3-dioxygenase induced by dexamethasone alone. Therefore, dexamethasone alone or together with glucagon stimulated transcription of tryptophan 2,3-dioxygenase increasing its mRNA and enzyme synthesis in hepatocytes. Conversely, insulin and epinephrine suppressed these increases of mRNA synthesis and thus decreased enzyme synthesis. .

Regulation of angiotensin-converting enzyme

Regulation of angiotensin-converting enzyme. Fyhrquist, Frej; Gronhagen-Riska, Carola; Hortling, Lars; Forslund, Terje; Tikkanen, Ilkka (Minerva Inst. Med. Res., Helsinki SF-00101/10, Finland). J. Hypertens., 1(Suppl. 1), 25-30 (English) 1983. CODEN: JOHYD3. DOCUMENT TYPE: Journal CA Section: 13 (Mammalian Biochemistry) Section cross-reference(s): 1, 2, 14 Angiotensin-converting enzyme (I; EC 3.4.15.1) was studied in human serum, cultured endothelial cells from umbilical cord artery, and macrophages. I activity in serum was detd. by an enzyme kinetic assay with a tripeptide substrate and with a method using an 125I-labeled specific inhibitor of I as a sensitive probe for I binding sites. The latter method was also used to quantitate I in cells. 50-02-2 and 62571-86-2 are also in the experiment. Immunofluoresce was another method to det. I in human cells. Dexamethasone treatment caused an increase in I in cultured human endothelial cells and macrophages. Captopril and enalapril treatment of hypertensive patients increased total serum I, the increase being evident after removal of the active drug from the serum by prolonged storage or chloramine T treatment (captopril) or by dialysis (enalapril). Captopril also increased the I content of endothelial cells and macrophages. Macrophages were apparently sensitive to captopril induction of I biosynthesis after prestimulation with Escherichia coli lipopolysaccharide. Previous studies with rat serum and lung plasma membrane I regulation are discussed. Apparently, I biosynthesis may be enhanced by glucocorticoids, macrophage activation, and I inhibitors. .