Hossner K L, Holland M D, Williams S E, Wallace C R, Niswender G D, Odde K G
Department of Animal Sciences, Colorado State University, Fort Collins 80523, USA.
Domest Anim Endocrinol. 1997 Sep;14(5):316-24. doi: 10.1016/s0739-7240(97)00026-x.
This study was designed to examine the effects of fetal growth potential on maternal hormones and lipid metabolism. Sixty beef heifers were inseminated with semen from sires with high (H) or low (L) expected progeny differences for birth weight. Maternal serum was collected at 21-d intervals from Day 85 to Day 274 of gestation. Serum concentrations of insulin-like growth factor (IGF)-I, IGF-II, placental lactogen (PL), and nonesterified fatty acids (NEFA) were determined and correlated to fetal and maternal characteristics. Maternal serum IGF-I declined throughout pregnancy, whereas IGF-II was relatively constant and PL tended to increase. Maternal serum NEFA was low and invariant through Day 211 of gestation when it rose 3.5 times to peak levels at Day 253 and declined at Day 274. PL was positively correlated to NEFA (r = 0.37, P < 0.01), IGF-I was negatively correlated (P < 0.01) to NEFA and PL (r = -0.59, and -0.35, respectively), and IGF-II was negatively correlated to NEFA (r = -0.35, P < 0.01). Dams pregnant with H fetuses had lower (P = 0.02) serum IGF-I and tended to have higher (P = 0.09) serum PL concentrations than dams carrying L fetuses. Additionally, dams pregnant with L fetuses had higher (P < 0.03) serum IGF-II concentrations than dams with H fetuses (175.6 vs. 145.0 ng/ml) during the third trimester. Fetal sex had no effect on any maternal serum parameter. Fetal weight and instantaneous growth rate (IGR) were positively correlated to maternal NEFA and PL and negatively correlated to maternal IGF-I and IGF-II. Independent IGR effects were detected for PL (P < 0.06) and IGF-I (P < 0.0005) concentrations. Maternal hip height was negatively related to serum IGF-I and positively related to serum PL concentrations. Maternal body weight and body condition score were correlated with several serum parameters but were confounded by day of gestation. Correlation analysis of serum concentrations of IGF-I, IGF-II, and PL did not support the hypothesis that PL regulates IGF concentrations.
本研究旨在探讨胎儿生长潜力对母体激素和脂质代谢的影响。选用60头肉用小母牛，用出生体重预期后代差异高（H）或低（L）的公牛精液进行人工授精。在妊娠第85天至第274天期间，每隔21天采集一次母血清。测定胰岛素样生长因子（IGF）-I、IGF-II、胎盘催乳素（PL）和非酯化脂肪酸（NEFA）的血清浓度，并将其与胎儿和母体特征进行关联分析。整个孕期母血清IGF-I下降，而IGF-II相对恒定，PL则呈上升趋势。妊娠第211天前母血清NEFA较低且无变化，之后在第253天升至峰值水平（升高3.5倍），并在第274天下降。PL与NEFA呈正相关（r = 0.37，P < 0.01），IGF-I与NEFA和PL呈负相关（P < 0.01，r分别为 -0.59和 -0.35），IGF-II与NEFA呈负相关（r = -0.35，P < 0.01）。怀有H胎儿的母牛血清IGF-I较低（P = 0.02），血清PL浓度往往较高（P = 0.09），而怀有L胎儿的母牛则相反。此外，在妊娠晚期，怀有L胎儿的母牛血清IGF-II浓度高于怀有H胎儿的母牛（175.6对145.0 ng/ml，P < 0.03）。胎儿性别对任何母血清参数均无影响。胎儿体重和瞬时生长率（IGR）与母血清NEFA和PL呈正相关，与母血清IGF-I和IGF-II呈负相关。检测到PL（P < 0.06）和IGF-I（P < 0.0005）浓度存在独立的IGR效应。母体髋高与血清IGF-I呈负相关，与血清PL浓度呈正相关。母体体重和体况评分与多个血清参数相关，但受妊娠天数的影响。IGF-I、IGF-II和PL血清浓度的相关性分析不支持PL调节IGF浓度的假说。
