Blom A K, Hove K, Nedkvitne J J
Acta Endocrinol (Copenh). 1976 Jul;82(3):553-60. doi: 10.1530/acta.0.0820553.
The pregnant ewe compensates the reduced carbohydrate availability in late pregnancy by increased fat combustion. The purpose of the present study was to examine the adaptation of plasma growth hormone (GH) and insulin levels to this change in energy substrate metabolism. Two groups of ewes were bled in the post-absorptive state at different stages of pregnancy. One group (7 animals) was fed adequately throughout pregnancy, while the other received a maintenance ration for non-pregnant sheep (28 animals). Plasma GH increased from averages from 2-3 to 8-14 ng/ml during the last month before lambing. Shearing of the wool combined with a cold stress resulted in a clearly detectable peak in plasma GH in the underfed sheep. No significant difference in plasms GH attributable to differences in diet could be detected in late pregnancy. Plasma insulin decreased steadily the last 5 weeks towards lambing, most in mothers with 3 lambs. Plasma free fatty levels (FFA) increased the last 2 months of pregnancy, most in the underfed sheep. GH and FFA were positively correlated (r= 0.50 and 0.30 in the two groups). It is concluded that the adaptation of the maternal metabolism to reduced carbohydrate - and eventually energy-availability in late pregnancy included lowering of insulin and enhancement of plasms GH levels. These adaptations were detectable under the present conditions the last 5-6 weeks before term.
怀孕母羊通过增加脂肪燃烧来补偿妊娠后期碳水化合物供应的减少。本研究的目的是研究血浆生长激素（GH）和胰岛素水平对能量底物代谢变化的适应性。两组母羊在妊娠不同阶段的吸收后状态下采血。一组（7只动物）在整个妊娠期都给予充足的饲料，而另一组（28只动物）则给予非怀孕母羊的维持日粮。在产羔前的最后一个月，血浆GH水平从平均2 - 3 ng/ml增加到8 - 14 ng/ml。剪毛并结合冷应激导致营养不足母羊的血浆GH出现明显可检测的峰值。在妊娠后期，未检测到因饮食差异导致的血浆GH有显著差异。在接近产羔的最后5周，血浆胰岛素水平持续下降，怀3只羔羊的母羊下降最为明显。在妊娠的最后2个月，血浆游离脂肪酸（FFA）水平升高，营养不足的母羊升高最为明显。GH和FFA呈正相关（两组的r分别为0.50和0.30）。得出的结论是，母体代谢对妊娠后期碳水化合物减少以及最终能量供应减少的适应性包括胰岛素水平降低和血浆GH水平升高。在当前条件下，这些适应性变化在预产期前的最后5 - 6周可以检测到。
