Androgen receptor immunoreactivity of male rat cervical motor neurons is increased by chronic pharmacologic testosterone treatment.

Chronic pharmacologic testosterone treatment of adult male rats decreases neuromuscular transmission failure (NTF) in the rat diaphragm muscle and increases choline acetyltransferase (ChAT) mRNA levels in cervical motor neurons. These testosterone-induced changes in NTF and ChAT mRNA levels may be mediated through the activation of the androgen receptor (AR). The purpose of this study was to determine if the AR expression of cervical motor neurons is modulated by chronic pharmacologic testosterone treatment of gonadally intact male rats with testosterone propionate (TP).

Monitoring protein kinase and phosphatase reactions with matrix-assisted laser desorption/ionization mass spectrometry and capillary zone electrophoresis: comparison of the detection efficiency of peptide-phosphopeptide mixtures.

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) and capillary zone electrophoresis (CZE) were evaluated for monitoring protein phosphatase and kinase reactions in vitro. Varying concentrations of peptide C (YIHLEKKYVRRDSG), peptide S (YLIEDNEYTARQGA) and kemptide (LARRSALG) mixed with their corresponding phosphorylated peptides, pC, pS and pkemptide, were analyzed. Comparison between the two techniques indicated that MALDI MS was less quantitative than CZE, showing a bias towards detection of the unphosphorylated peptide S and kemptide.