Felder K J, Klindt J, Bolt D J, Anderson L L
Department of Animal Science, Iowa State University, Ames 50011.
Endocrinology. 1988 May;122(5):1751-60. doi: 10.1210/endo-122-5-1751.
Plasma levels of relaxin and progesterone in hysterectomized and pregnant gilts were determined from days 100-120 to evaluate the effects of purified porcine (p) LH and pPRL on the secretory activity of the aging corpora lutea. Gilts were bred on the second observed estrus or were hysterectomized between 6-8 days after estrus (estrus = day 0) and were assigned randomly to one of three treatment groups; saline-treated control, im injections of pLH, and iv injections of pPRL from days 110-120. In control, pLH-treated, and pPRL-treated animals, average gestation lengths were 114 +/- 0.8, 116 +/- 1.9, and 115 +/- 0.5 days (+/- SE), respectively. The relaxin level in mated gilts on day 100 was less than 2 ng/ml; it began to increase after day 110 and peaked in control animals on day 113 (66 ng/ml), whereas in pLH- and pPRL-treated animals, prepartum peak values were greater (P less than 0.01) and occurred on days 113 (104 ng/ml) and 114 (117 ng/ml), respectively. Relaxin dropped to basal levels (less than 1 ng/ml) by day 115 in controls and by day 116 in both pLH- and pPRL-treated gilts. Although pLH and pPRL treatments markedly accentuated peak relaxin secretion, they did not significantly accelerate or delay parturition or delay the abrupt demise of the corpora lutea immediately postpartum. In hysterectomized gilts, relaxin began to increase after day 110, peaked in control animals on day 113 (27 ng/ml), and decreased abruptly thereafter to less than 4 ng/ml. In contrast, pLH caused an immediate release of relaxin on day 111 (23 ng/ml) and sustained elevated levels (P less than 0.01) of relaxin until day 118, but the original corpora lutea regressed. Relaxin in pPRL-treated animals increased steadily after day 110, reaching peak values by day 115 (29 ng/ml), and remained consistently elevated (P less than 0.01) until day 120. Progesterone secretion was maintained in the pPRL-treated hysterectomized gilts from days 110-120 by the original corpora lutea and with no luteinization of follicles or formation of new corpora lutea. It is evident from this study that administration of pPRL starting on day 110 enhanced and prolonged the preprogramed release of relaxin and maintained progesterone secretion by aging corpora lutea in hysterectomized animals until day 120.
在第100至120天测定了子宫切除和怀孕后备母猪的血浆松弛素和孕酮水平，以评估纯化的猪（p）促黄体生成素（LH）和p催乳素（PRL）对老化黄体分泌活性的影响。后备母猪在第二次观察到的发情期配种，或在发情后（发情期=第0天）6 - 8天进行子宫切除，并随机分配到三个治疗组之一；生理盐水处理的对照组、第110至120天肌肉注射pLH以及静脉注射pPRL。在对照、pLH处理和pPRL处理的动物中，平均妊娠期分别为114±0.8、116±1.9和115±0.5天（±标准误）。配种后备母猪第100天的松弛素水平低于2 ng/ml；第110天后开始升高，对照组动物在第113天达到峰值（66 ng/ml），而在pLH和pPRL处理的动物中，产前峰值更高（P<0.01），分别出现在第113天（104 ng/ml）和第114天（117 ng/ml）。对照组中，松弛素在第115天降至基础水平（低于1 ng/ml）；pLH和pPRL处理的后备母猪在第116天降至基础水平。尽管pLH和pPRL处理显著增强了松弛素分泌峰值，但它们并未显著加速或延迟分娩，也未延迟产后黄体的突然退化。在子宫切除的后备母猪中，松弛素在第110天后开始升高，对照组动物在第113天达到峰值（27 ng/ml），此后突然降至低于4 ng/ml。相比之下，pLH在第111天导致松弛素立即释放（23 ng/ml），并使松弛素水平持续升高（P<0.01）直至第118天，但原始黄体退化。pPRL处理的动物中，松弛素在第110天后稳步升高，到第115天达到峰值（29 ng/ml），并一直持续升高（P<0.01）直至第120天。在第110至120天，pPRL处理的子宫切除后备母猪中的孕酮分泌由原始黄体维持，且无卵泡黄体化或新黄体形成。从这项研究可以明显看出，从第110天开始给予pPRL可增强并延长预先设定的松弛素释放，并维持子宫切除动物中老化黄体的孕酮分泌直至第120天。
