Koshika S, Hosaka M, Tarui M, Furuyama M, Nakayama Y
Department of Biochemistry, Kanagawa Dental College, Yokosuka, Japan.
Biochem Int. 1987 Oct;15(4):761-8.
The properties of 5 alpha-reductase activity in the submandibular glands of rats were investigated using microsomal fraction in the presence of NADPH, and we found a sexual difference in these properties. The formation of 5 alpha-dihydrotestosterone and 5 alpha-androstane-3 alpha, 17 beta-diol from testosterone demonstrated 5 alpha-reductase in the rat microsomal fraction of this tissue sample. Apparent michaelis constants (Km) of the 5 alpha-reductase activity for testosterone was 1.02 x 10(-6) M for the female tissue. Microsomal fraction of submandibular glands of male rats had two Kms and were determined as 1.12 x 10(-6) M and 1.01 x 10(-5) M. The lower Km of 5 alpha-reductase for male rats was similar to for the females.
利用微粒体部分，在烟酰胺腺嘌呤二核苷酸磷酸（NADPH）存在的情况下，对大鼠下颌下腺中5α-还原酶活性的特性进行了研究，我们发现这些特性存在性别差异。从睾酮形成5α-二氢睾酮和5α-雄甾烷-3α,17β-二醇证明了该组织样本大鼠微粒体部分存在5α-还原酶。雌性组织中5α-还原酶活性对睾酮的表观米氏常数（Km）为1.02×10⁻⁶M。雄性大鼠下颌下腺的微粒体部分有两个Km值，分别测定为1.12×10⁻⁶M和1.01×10⁻⁵M。雄性大鼠5α-还原酶较低的Km值与雌性相似。
