Estienne M J, Schillo K K, Hileman S M, Green M A, Hayes S H, Boling J A
Department of Animal Sciences, University of Kentucky, Lexington 40546-0215.
Endocrinology. 1990 Apr;126(4):1934-40. doi: 10.1210/endo-126-4-1934.
The effects of FFA on circulating LH and GH concentrations in ovariectomized ewe lambs were investigated. Lambs (n = 14) were weaned at 2.5 months, ovariectomized at 6.5 months, and used at 8.5 months of age. From weaning until day 0 of the experiment, lambs were fed to maintain body weights (23 kg). On day 0, serum FFA concentrations and mean serum LH concentrations and number and amplitude of LH pulses, as assessed in blood samples collected every 12 min for 4 h, were 6.4 +/- 0.6 mg/100 ml, 0.57 +/- 0.08 ng/ml, 0.45 +/- 0.09 pulses/h, and 0.73 +/- 0.11 ng/ml, respectively. Double the maintenance feeding, beginning day 1, increased (P less than 0.01) body weights by 16% and LH pulse frequency by 82%, but had no effect (P greater than 0.1) on FFA concentrations, mean LH concentrations, or LH pulse amplitude by day 14. On day 14, lambs were infused with lipid (n = 9; 95.8 mg/min) or 0.9% saline solution (n = 5) for 8 h. Blood samples were collected at 12-min intervals for 12 h, beginning 4 h before infusions. FFA levels increased (P less than 0.01) in lipid-infused animals to 27.6 +/- 2.9 mg/100 ml by 4 h of infusion. Mean LH concentrations and LH pulse frequency and amplitude were unaffected (P greater than 0.1) by treatment. In contrast, mean GH concentrations and GH pulse frequency, which were similar (P greater than 0.1) between groups before infusion (14.0 +/- 0.8 ng/ml and 0.36 +/- 0.07 pulses/h, respectively) were decreased by FFA treatment by 51% (P less than 0.01) and 81% (P less than 0.006), respectively. GH pulse amplitude was highly variable and unaffected (P greater than 0.1) by treatment. In summary, elevated FFA levels appear to inhibit the release of GH, but not LH, in the ovariectomized ewe lamb.
研究了游离脂肪酸（FFA）对去卵巢母羊幼崽循环中促黄体生成素（LH）和生长激素（GH）浓度的影响。14只幼崽在2.5月龄时断奶，6.5月龄时去卵巢，并在8.5月龄时使用。从断奶到实验第0天，幼崽按维持体重（23千克）进行饲养。在第0天，血清FFA浓度、平均血清LH浓度以及LH脉冲的数量和幅度（通过每12分钟采集一次血样，持续4小时进行评估）分别为6.4±0.6毫克/100毫升、0.57±0.08纳克/毫升、0.45±0.09次脉冲/小时和0.73±0.11纳克/毫升。从第1天开始将饲养量增加一倍，使体重增加了16%（P<0.01），LH脉冲频率增加了82%，但在第14天时对FFA浓度、平均LH浓度或LH脉冲幅度没有影响（P>0.1）。在第14天，给9只幼崽输注脂质（95.8毫克/分钟），给5只幼崽输注0.9%的盐溶液，持续8小时。在输注前4小时开始，每隔12分钟采集一次血样，共采集12小时。输注脂质的动物在输注4小时时FFA水平升高（P<0.01）至27.6±2.9毫克/100毫升。治疗对平均LH浓度、LH脉冲频率和幅度没有影响（P>0.1）。相比之下，输注前两组之间相似（P>0.1）的平均GH浓度和GH脉冲频率（分别为14.0±0.8纳克/毫升和0.36±0.07次脉冲/小时），经FFA处理后分别降低了51%（P<0.01）和81%（P<0.006）。GH脉冲幅度变化很大，治疗对其没有影响（P>0.1）。总之，在去卵巢母羊幼崽中，升高的FFA水平似乎抑制GH的释放，但不抑制LH的释放。
