Lukyanenko Yevgeniya, Chen Jau-Jiin, Hutson James C
Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, USA.
Biol Reprod. 2002 Nov;67(5):1435-8. doi: 10.1095/biolreprod.102.007575.
Recently, we found that testicular macrophages produce 25-hydroxycholesterol (25-HC) and express 25-hydroxylase, the enzyme that converts cholesterol to 25-HC. In addition, 25-HC may be an important paracrine factor mediating the known interactions between macrophages and neighboring Leydig cells, because it is efficiently converted to testosterone by Leydig cells. The purpose of the present study was to determine if testosterone can regulate the production of 25-HC in rat testicular macrophages, representing a potential negative-feedback loop from Leydig cells. We found that expression of 25-hydroxylase mRNA and production of 25-HC by cultured testicular macrophages were significantly inhibited by testosterone at 10 micro g/ml. This dose of testosterone did not have an effect on cell viability and did not change the rate of mRNA degradation in the presence of actinomycin D. These studies indicate that production of 25-HC is negatively regulated by testosterone, which may be representative of a paracrine negative-feedback loop.
最近，我们发现睾丸巨噬细胞可产生25-羟胆固醇（25-HC）并表达25-羟化酶，该酶可将胆固醇转化为25-HC。此外，25-HC可能是介导巨噬细胞与相邻睾丸间质细胞之间已知相互作用的重要旁分泌因子，因为它可被睾丸间质细胞有效地转化为睾酮。本研究的目的是确定睾酮是否能调节大鼠睾丸巨噬细胞中25-HC的产生，这代表了睾丸间质细胞潜在的负反馈回路。我们发现，10μg/ml的睾酮可显著抑制培养的睾丸巨噬细胞中25-羟化酶mRNA的表达及25-HC的产生。该剂量的睾酮对细胞活力没有影响，且在放线菌素D存在的情况下不会改变mRNA的降解速率。这些研究表明，睾酮对25-HC的产生具有负调节作用，这可能代表了一种旁分泌负反馈回路。
