Characterization of C- and N-terminal forms of angiotensin (Ang) peptides mandated assessment of methods to determine plasma levels. 125I-Ang I, 125I-Ang II, and 125I-Ang(1-7) were added to blood samples in the presence of protease inhibitors. Ethylenediaminetetraacetic acid (EDTA) inhibited the conversion of 125I-Ang I to 125I-Ang II. o-Phenanthroline and EDTA (EDTA + o-Ph) did not eliminate [des-Asp1] fragments or 125I-Ang(1-7). The combination of EDTA + o-Ph and pepstatin A or 4-(chloromercuri) benzoic acid (PCMB) significantly reduced 125I-Ang(1-7) generation. Only PCMB plus EDTA + o-Ph eliminated [des-Asp1] fragments. Authentic plasma values of Ang peptides require the correct choice of protease inhibitors.

Angiotensin I↗

PubMedDate not supplied

DNA microarray analysis of genes involved in the process of differentiation in mouse Leydig cell line TTE1.

A Leydig cell line, TTE1, was established from the temperature-sensitive simian virus 40 large T-antigen transgenic mice. The cells showed temperature-sensitive growth characteristics and a differentiated phenotype at a nonpermissive temperature. To identify differentially expressed genes in the process of Leydig cell differentiation, the authors carried out microarray analysis of TTE1 cells cultured at permissive and nonpermissive temperatures. The resulting fluorescence-labeled cDNAs synthesized from mRNAs were hybridized with Clontech's Atlas glass mouse 1.0 microarrays. Of the 1081 genes analyzed, the levels of 31 genes were changed, with 24 genes showing increased levels of expression and the remaining 7 genes showing decreased levels. Tie2 was the most changed transcript, with a 13.5-fold upregulation under the differentiated condition. The authors believe this to be the first report of broadscale gene expression in Leydig cell differentiation using the microarray technology. The ability to analyze broadscale gene expression in this manner provides a powerful tool for investigating the molecular mechanisms of Leydig cell functions.

Animals↗

PubMedDate not supplied

Establishment of Leydig cell line, TTE1, from transgenic mice harboring temperature-sensitive simian virus 40 large T-antigen gene.

A Leydig cell line, TTE1, has been established from transgenic mice harboring a temperature-sensitive simian virus 40 (tsSV40) large T-antigen gene. The cells grew at a permissive temperature (33 degrees C), but growth was markedly prevented at a nonpermissive temperature (39 degrees C). T-antigen was expressed in the nuclei at 33 degrees C but disappeared at 39 degrees C, indicating that the cells show a temperature-sensitive growth phenotype reflected by the tsSV40 large T-antigen. TTE1 cells did not show any colony-forming activity in soft agar and form tumors in subcutaneous tissue in nude mice, indicating that the cells were not transformed. Alkaline phosphatase and 3beta-hydroxysteroid dehydrogenase (HSD) activities or expression of cytokeratin and vimentin were observed. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that TTE1 cells expressed mRNAs encoding 17beta-HSD types 1 and 3, and inhibin-alpha. The cells with unique characteristics, therefore, should serve useful model study the function of Leydig cell.

17-Hydroxysteroid Dehydrogenases↗

PubMedDate not supplied

MR imaging of chronic cerebral paragonimiasis.

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Adult↗