Effects of phytoestrogens on testosterone production of rat Leydig cells / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the effects of phytoestrogens (daidzein and genistein) on the testosterone production of rat Leydig cells and the possible mechanisms.</p><p><b>METHODS</b>Primary Leydig cells were obtained from 3-month old male SD rats using discontinuous Percoll density gradient centrifugation. The effects of phytoestrogens at various concentrations were evaluated by ELISA, with hCG as the positive control. The mRNA expression of P450 side-chain cleavage enzyme (P450scc) was analyzed by semi-quantitative RT-PCR.</p><p><b>RESULTS</b>Genistein at 0.1 micromol/L obviously promoted the secretion of testosterone and upregulated the mRNA level of P450scc. At a higher concentration of 5 micromol/L, however, both daidzein and genistein significantly inhibited the testosterone production of Leydig cells (P > 0.05).</p><p><b>CONCLUSION</b>Genistein can promote the testosterone production of Leydig cells at a low concentration (0.1 micromol/L), but both daidzein and genistein can inhibit it at a higher concentration ( >5 micromol/L).</p>

Interaction between strychnine and bovine serum albumin / 药学学报

<p><b>AIM</b>To study the interaction between strychnine and bovine serum albumin.</p><p><b>METHODS</b>Fluorescence spectroscopy and ultraviolet spectroscopy were used.</p><p><b>RESULTS</b>The static quenching and the non-radiation energy transfer are the two main reasons to leading the fluorescence quenching of BSA. The apparent combining constants (K(A)) between strychnine and BSA are 3.72 x 10(3) at 27 degrees C, 4.27 x 10(3) at 37 degrees C, 4.47 x 10(3) at 47 degrees C and the combining sites are 1.01 +/- 0.03. The combining distance (r = 3.795 nm) and energy transfer efficiency (E = 0.0338) are obtained by Förster's non-radiation energy transfer mechanism.</p><p><b>CONCLUSION</b>The interaction between strychnine and BSA was driven mainly by hydrophobic force.</p>