Trout W E, Hall J A, Stallings-Mann M L, Galvin J M, Anthony R V, Roberts R M
Department of Animal Sciences, University of Missouri, Columbia 65211.
Endocrinology. 1992 May;130(5):2557-64. doi: 10.1210/endo.130.5.1572282.
The endometrium of the pig secretes retinol-binding protein (RBP) under the influence of progesterone (P4). The objective of this study was to determine how conceptus-derived estrogen might modulate this production of RBP around days 11-13 of pregnancy when conceptuses elongate from spheres to long thread-like forms. Concentrations of retinol and RBP were low (35 +/- 7 ng/ml) in uterine flushings obtained on days 10-12 of the estrous cycle or from pregnant gilts in which conceptuses had not elongated. Concentrations of retinol and RBP increased 7- to 8-fold (P less than 0.01) in flushings where filamentous conceptuses were present. Size exclusion and ion exchange chromatography demonstrated that virtually all retinol assayed in uterine flushings was associated with RBP. Northern blot analysis with a cDNA representing uterine RBP revealed a single endometrial mRNA 1.1 kilobases in length. Expression of RBP mRNA in uterine endometrium was measured in ovariectomized prepubertal gilts after the administration of steroids according to the following regimens: I, corn oil (days 0-16; n = 10); II, estradiol benzoate (EB; days 13-14; n = 11); III, EB (days 1-2; n = 12); IV, EB (days 1-2) plus P4 (days 3-16; n = 12); and V, EB (days 1-2) plus P4 (days 3-16) plus EB (days 13-14; n = 12). EB (200 micrograms) and P4 (100 mg) were administered twice daily. Treatment IV was designed to stimulate the estrous cycle, and treatment V simulated early pregnancy. All gilts were hysterectomized on day 16, and total uterine mRNA (3 micrograms) was analyzed by Northern blotting. No RBP mRNA was detected in groups I, II, or III. In group IV, 5 of 12 gilts had detectable RBP mRNA, as measured by densitometric scanning (OD = 0.35 +/- 0.14). RNA isolated from all gilts in group V (12 of 12) gave a strong hybridization signal (OD = 1.58 +/- 0.22) for RBP. Finally, RBP mRNA was examined in the uterine endometrium of mature gilts on day 13 of the estrous cycle (n = 4), day 13 of pseudopregnancy (2.5 mg EB given on days 11-12; n = 4), or day 13 of pregnancy after conceptuses had elongated (n = 4). RBP mRNA was present in all groups, but was enhanced approximately 12-fold (P less than 0.01) in pregnant and pseudopregnant gilts compared to that in control gilts.(ABSTRACT TRUNCATED AT 400 WORDS)
猪的子宫内膜在孕酮（P4）的影响下分泌视黄醇结合蛋白（RBP）。本研究的目的是确定在妊娠第11 - 13天，当孕体从球形伸长为长丝状时，孕体来源的雌激素如何调节这种RBP的产生。在发情周期第10 - 12天或来自孕体未伸长的妊娠母猪的子宫冲洗液中，视黄醇和RBP的浓度较低（35±7 ng/ml）。在存在丝状孕体的冲洗液中，视黄醇和RBP的浓度增加了7至8倍（P<0.01）。尺寸排阻色谱和离子交换色谱表明，子宫冲洗液中检测到的几乎所有视黄醇都与RBP相关。用代表子宫RBP的cDNA进行Northern印迹分析，发现子宫内膜有一个长度为1.1千碱基的单一mRNA。按照以下方案对去卵巢的青春期前母猪给予类固醇后，测量子宫子宫内膜中RBP mRNA的表达：I，玉米油（第0 - 16天；n = 10）；II，苯甲酸雌二醇（EB；第13 - 14天；n = 11）；III，EB（第1 - 2天；n = 12）；IV，EB（第1 - 2天）加P4（第3 - 16天；n = 12）；V，EB（第1 - 2天）加P4（第3 - 16天）加EB（第13 - 14天；n = 12）。每天两次给予EB（200微克）和P4（100毫克）。方案IV旨在刺激发情周期，方案V模拟早期妊娠。所有母猪在第16天进行子宫切除，通过Northern印迹分析3微克子宫总mRNA。在I、II或III组中未检测到RBP mRNA。在IV组中，通过光密度扫描测量（OD = 0.35±0.14），12头母猪中有5头可检测到RBP mRNA。从V组所有母猪（12/12）分离的RNA对RBP产生强烈的杂交信号（OD = 1.58±0.22）。最后，在发情周期第13天（n = 4）、假孕第13天（第11 - 12天给予2.5毫克EB；n = 4）或孕体伸长后的妊娠第13天（n = 4）的成年母猪子宫子宫内膜中检测RBP mRNA。所有组中均存在RBP mRNA，但与对照母猪相比，妊娠和假孕母猪中的RBP mRNA增强了约12倍（P<0.01）。（摘要截断于400字）
