Couet J, Martel C, Labrie Y, Luo S, Simard J, Labrie F
Medical Research Council Group in Molecular Endocrinology, CHUL Research, Ste-Foy, Quebec, Canada.
J Invest Dermatol. 1994 Jul;103(1):60-4. doi: 10.1111/1523-1747.ep12389663.
In rat skin, type IV is the major 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) isoenzyme expressed. Although types I and II 3 beta-HSD mRNAs are also present in the skin, their level of expression is about two orders of magnitude lower than that of type IV. In this study, we have investigated the control of type IV 3 beta-HSD mRNA levels as well as 3 beta-HSD enzymatic activity in hypophysectomized adult rats of both sexes. Skin 3 beta-HSD activity was measured by the conversion of [14C]-dehydroepiandrosterone into [14C]-androstenedione, whereas ribonuclease protection assay using a specific type IV cRNA probe was used to assess mRNA levels. Intact male and female rats show a similar level of skin 3 beta-HSD activity, although hypophysectomy caused opposite effects, a decrease being observed in males while an increase was observed in hypophysectomized female animals. We next studied the effects of hyperprolactinemia, corticosterone and 1-thyroxine in hypophysectomized animals. L-thyroxine was found to stimulate 3 beta-HSD expression and activity in male rats whereas no significant effect was observed on the already elevated levels in hypophysectomized female rats. Corticosterone caused an inhibition of type IV 3 beta-HSD mRNA levels and activity in both male and female animals. Hyperprolactinemia achieved by pituitary implants inserted under the kidney capsule stimulated the expression of type IV mRNA as well as 3 beta-HSD enzymatic activity in hypophysectomized male and female animals. The present data demonstrate the multihormonal regulation of 3 beta-HSD/isomerase expression and activity in the rat skin.
在大鼠皮肤中，IV型是主要表达的3β-羟基类固醇脱氢酶/δ5-δ4异构酶（3β-HSD）同工酶。尽管I型和II型3β-HSD mRNA也存在于皮肤中，但其表达水平比IV型低约两个数量级。在本研究中，我们调查了两性去垂体成年大鼠中IV型3β-HSD mRNA水平以及3β-HSD酶活性的调控情况。通过将[14C]-脱氢表雄酮转化为[14C]-雄烯二酮来测定皮肤3β-HSD活性，而使用特异性IV型cRNA探针的核糖核酸酶保护测定法用于评估mRNA水平。完整的雄性和雌性大鼠显示出相似水平的皮肤3β-HSD活性，尽管去垂体导致了相反的效应，雄性大鼠中观察到活性降低，而去垂体的雌性动物中观察到活性增加。接下来，我们研究了高催乳素血症、皮质酮和L-甲状腺素对去垂体动物的影响。发现L-甲状腺素刺激雄性大鼠中3β-HSD的表达和活性，而对去垂体雌性大鼠中已经升高的水平未观察到显著影响。皮质酮在雄性和雌性动物中均导致IV型3β-HSD mRNA水平和活性的抑制。通过植入肾被膜下的垂体实现的高催乳素血症刺激了去垂体雄性和雌性动物中IV型mRNA的表达以及3β-HSD酶活性。目前的数据证明了大鼠皮肤中3β-HSD/异构酶表达和活性的多激素调控。
