Orava M, Voutilainen R, Vihko R
Department of Clinical Chemistry, University of Oulu, Finland.
Mol Endocrinol. 1989 Jun;3(6):887-94. doi: 10.1210/mend-3-6-887.
The inhibitory effects of recombinant porcine interferon-gamma (IFN gamma) on human CG (hCG)-stimulated testosterone production, and on mRNA concentrations of cholesterol side-chain cleavage (P450scc) and 17 alpha-hydroxylase/C17-20lyase (P450c 17) were investigated using porcine primary Leydig cell culture as a model. After preincubation of Leydig cells for 24 h with 1000 pM IFN gamma, hCG-stimulated (10 ng/ml, 2 h) testosterone production was inhibited by 50%, whereas no significant changes were seen in hCG-stimulated cAMP production. Incubation with 10 microM 5-cholestene-3 beta,22(R)-diol or 10 microM 5-cholestene-3 beta,20 alpha-diol together with hCG (10 ng/ml, 2 h) reversed most of the inhibitory effect of IFN gamma, suggesting that IFN gamma inhibits P450scc activity, possibly by inhibiting the substrate (cholesterol) availability for P450scc. Incubation with IFN gamma also decreased basal concentrations of P450scc (45%) and P450c 17 (35%) mRNA, although these changes probably did not contribute to the decreased testosterone production. Long-term treatment with hCG (100 ng/ml, 24 h) increased P450scc mRNA (3- to 4-fold) and P450c 17 mRNA (4- to 5-fold) concentrations. Simultaneous treatment with IFN gamma attenuated these hCG-induced increases in P450scc mRNA (50%) and P450c 17 mRNA (40-100%) concentrations, as well as in testosterone production (77%). This inhibition of testosterone production could only be partly reversed by the hydroxylated cholesterol derivatives. This suggests that in addition to possible suppression of cholesterol availability, decreased P450scc and/or P450c 17 activities (through decreased mRNA concentrations) were also involved in the IFN gamma suppressed steroidogenic capacity of porcine Leydig cells during long-term hCG stimulation.
以猪原代睾丸间质细胞培养为模型，研究了重组猪γ干扰素（IFNγ）对人绒毛膜促性腺激素（hCG）刺激的睾酮生成，以及对胆固醇侧链裂解酶（P450scc）和17α-羟化酶/C17-20裂解酶（P450c17）mRNA浓度的抑制作用。用1000 pM IFNγ预孵育睾丸间质细胞24小时后，hCG刺激（10 ng/ml，2小时）的睾酮生成受到50%的抑制，而hCG刺激的环磷酸腺苷（cAMP）生成未见明显变化。与10 μM 5-胆甾烯-3β,22(R)-二醇或10 μM 5-胆甾烯-3β,20α-二醇与hCG（10 ng/ml，2小时）一起孵育可逆转IFNγ的大部分抑制作用，这表明IFNγ可能通过抑制P450scc的底物（胆固醇）可用性来抑制P450scc活性。用IFNγ孵育也降低了P450scc（45%）和P450c17（35%）mRNA的基础浓度，尽管这些变化可能与睾酮生成减少无关。长期用hCG（100 ng/ml，24小时）处理可使P450scc mRNA（3至4倍）和P450c17 mRNA（4至5倍）浓度增加。同时用IFNγ处理可减弱hCG诱导的P450scc mRNA（50%）和P450c17 mRNA（40%至100%）浓度增加以及睾酮生成（77%）。睾酮生成的这种抑制作用只能部分被羟基化胆固醇衍生物逆转。这表明，除了可能抑制胆固醇可用性外，P450scc和/或P450c17活性降低（通过mRNA浓度降低）也参与了长期hCG刺激期间IFNγ对猪睾丸间质细胞类固醇生成能力的抑制。
