Conley A J, Christenson R K, Ford S P, Geisert R D, Mason J I
Cecil and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas 75235.
Endocrinology. 1992 Aug;131(2):896-902. doi: 10.1210/endo.131.2.1379167.
The following studies were performed to investigate levels of expression of steroidogenic enzymes in porcine conceptuses between days 12 and 21 postmating and to correlate these findings with estrogen levels in conceptus tissues. In the first experiment, levels of steroidogenic enzymes in individual day 12 blastocysts were examined by Western immunoblot analyses. In a second experiment, Northern blot, slot blot, and Western immunoblot analyses for 17 alpha-hydroxylase cytochrome P450 (P450(17) alpha) were performed on conceptus tissue pooled for each uterine horn of sows on days 12, 14, 16, and 21 postmating. On day 12, P450(17) alpha) protein was detectable in 6-mm blastocysts, with highest levels apparent in 10- to 15-mm (tubular) blastocysts. Filamentous blastocysts appeared to have less P450(17) alpha) protein than did littermate tubular blastocysts. Side-chain cleavage cytochrome P450 (P450scc) and aromatase cytochrome P450 (P450arom) followed a pattern similar to that of P450(17) alpha. 3 beta-Hydroxysteroid dehydrogenase was undetectable by Western analysis in blastocysts at the stages examined, but was detectable in placenta from fetuses at later stages of gestation. In pooled tissue, P450(17) alpha) protein and mRNA were greater in day 12 conceptuses than in conceptuses from all other days. However, transition from the tubular to the filamentous form on day 12 postmating was associated with a dramatic decline in the level of P450(17) alpha) mRNA. The conceptus 17 beta-estradiol concentration was highly correlated with immunoreactive P450(17) alpha) protein and hybridizable P450(17) alpha) mRNA over days 12, 14, 16, and 21 postmating. These data suggest that the decrease in blastocyst estrogen secretion occurring after the time of elongation in porcine conceptuses may be due to a decrease in P450(17) alpha expression.
进行了以下研究，以调查配种后12至21天猪胚胎中类固醇生成酶的表达水平，并将这些结果与胚胎组织中的雌激素水平相关联。在第一个实验中，通过蛋白质免疫印迹分析检测了单个第12天囊胚中类固醇生成酶的水平。在第二个实验中，对配种后第12、14、16和21天母猪每个子宫角收集的胚胎组织进行了17α-羟化酶细胞色素P450（P450(17)α）的Northern印迹、狭缝印迹和蛋白质免疫印迹分析。在第12天，在6毫米的囊胚中可检测到P450(17)α蛋白，在10至15毫米（管状）囊胚中水平最高。丝状囊胚的P450(17)α蛋白似乎比同窝的管状囊胚少。侧链裂解细胞色素P450（P450scc）和芳香化酶细胞色素P450（P450arom）的模式与P450(17)α相似。在所检查阶段的囊胚中，通过蛋白质免疫印迹分析未检测到3β-羟基类固醇脱氢酶，但在妊娠后期胎儿的胎盘中可检测到。在混合组织中，第12天胚胎中的P450(17)α蛋白和mRNA比其他所有天数的胚胎中的都多。然而，配种后第12天从管状形式向丝状形式的转变与P450(17)αmRNA水平的急剧下降有关。在配种后第12、14、16和21天，胚胎17β-雌二醇浓度与免疫反应性P450(17)α蛋白和可杂交的P450(17)αmRNA高度相关。这些数据表明，猪胚胎伸长后囊胚雌激素分泌的减少可能是由于P450(17)α表达的降低。
