在雄性哺乳動物，腦下腺前葉可分泌促黃體素，作用在睪丸曲細精管間的萊氏細胞上產生睪酮。因此睪酮的生物合成是受到下視丘及腦下腺前葉的調控。下視丘釋放促性腺激素釋放因此作用於腦下腺前葉，刺激腦下腺前葉釋放促黃體素作用在萊氏細胞，由萊氏細胞製造並分泌睪酮於血液中。本文大鼠睪丸之介紹萊氏細胞純化方法。將大鼠睪丸間隙細胞經由Percoll密度梯度的方法，分離收集所得純化每十萬個萊氏細胞與人類絨毛膜性促素或睪酮生物合成所須各階段前驅物包含膽固醇、孕烯醇酮、雄脂烯二酮，在34℃水浴箱培養後，收及培養液，檢測睪酮濃度。本文提供讀者對萊氏細胞之瞭解，期望能提供可靠的方法，應用於未來之研究。

In male mammals, testosterone is produced in the testicular interstitial cell after stimulation by luteinizing hormone (LH) released from the anterior pituitary gland. Testosterone biosynthesis is regulated by hypothalamus and anterior pituitary gland. Hypothalamus releases gonadotropin-releasing hormone (GnRH) to act on the anterior pituitary gland to release LH from pituitary gland and regulated Leydig cells. Leydig cells produces testosterone into the blood. Leydig cells could be purified by Percoll density gradient centrifugation method. Purified Leydig cells (1x10^5 cells/ml) were cultured with human chorionic gonadotropin (hCG) and steroidogenic precursors including 25-hydroxy-cholesterol, pregnenolone and androstenedione at 34℃. We hope to provide some technique informations to the readers to understand the preparation of rat Leydig cells and to create new idea in the future studies.