アブストラクト(17巻4号:神奈川歯学)

神奈川歯学

Japanese

Title : ラット顎下腺マイクロゾーム5α-Reductaseの性質
Subtitle : 原著
Authors : 高木忠雄
Authors(kana) :
Organization : 神奈川歯科大学生化学教室
Journal : 神奈川歯学
Volume : 17
Number : 4
Page : 468-480
Year/Month : 1983 / 3
Article : 原著
Publisher : 神奈川歯科大学学会
Abstract : 「緒言」 男性ホルモン標的臓器においては, 5α-Dihydrotestosterone(5α-DHT)の存在が重要な意義をもっている. すなわち, 5α-DHTはTestosterone(T)が5α-Reductase(5α-R)により5位に一つの水素が付加されたT還元物質で, Tの生理活性型と考えられているからである. それ故に, ラット顎下腺に5α-Rが存在し, T→5α-DHT→5α-Androstane 3α, 17β-diol(3α-Diol)の代謝経路が認められることは, ラット顎下腺が男性ホルモン標的臓器であることを示す有力な事実である. さらに, 成熟雄ラットにおいては, マイクロゾーム中の5α-RのTにたいするKm値は2種類あり, 一方雌のそれは1種であるという明らかな性差がある. しかもこのような性差は, 生後3週齢以後に始めて認めることが出来ると報告されている. しかし, 雄ラット5α-Rの2種類のKm値の実態については, まだ明確に実証されていない.
Practice : 歯科学
Keywords :

English

Title : Characteristics of the Microsomal 5α-Reductase of Rat Submandibular Gland
Subtitle :
Authors : Tadao TAKAGI
Authors(kana) :
Organization : Department of Biochemistry, Kanagawa Dental College
Journal : Kanagawa Shigaku
Volume : 17
Number : 4
Page : 468-480
Year/Month : 1983 / 3
Article : Original article
Publisher : Kanagawa Odontological Society
Abstract : Abstract : It is well known that the functions and characteristics of androgen target organs are dependent on the properties of 5α-reductase. This enzyme, a key enzyme in androgen target organs, has ability to convert testosterone into 5α-dihydrotestosterone. Therefore, the present study was designed to characterize 5α-reductase in male and female rat microsomes from submandibular glands by means of incubation procedure. When the concentration of testosterone-14C as a substrate was 1.08x10-6M 5α-reductase activity was decreased by the addition of progesterone, 20α-hydroxy-Δ4-pregnene-3-one, deoxycorticosterone, 20α-hydroxy-5α-pregnane-3-one, protease, corticosterone, cortisone, chlormadinone acetate, estradiol, hydrocortisone, estriol, 5α-pregnane-3β, 17α-diol, 5α-androstane-3α, 17β-diol or estrone to the incubation mixture. In this case, the most potent inhibitors of 5α-reductase activity were progesterone and 20α-hydroxy-Δ4-pregnene-3-one. However, when high concetration of substrate (29.4x10-6M) was incubated with the male microsome, the 5α-reductase activity was increased by the addition of hydrocortisone, estriol, chlormadinone acetate, corticosterone or cortisone. EGF, NGF, thyroxine or prolactin increase the 5α-reductase activity in both male and female microsomes from submandibular glands. In this case, the effect of thyroxine was the most potent. In the condition of high substrate concentration, the enzyme activity of male rats was decreased by LH or FSH, but in female rats the enzyme activity was increased only by FSH at low substrate concentration. The overall data suggest there are at least two different kind of 5α-reductases in male microsomes of submandibular glands in rats.
Practice : Dentistry
Keywords :