The fetal somatotropic axis during long term maternal undernutrition in sheep: evidence for nutritional regulation in utero.
The fetal somatotropic axis during long term maternal undernutrition in sheep: evidence for nutritional regulation in utero.
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DOI：
10.1210/endo.136.3.7867579
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发表时间：
1995-03
期刊：
影响因子：
4.8
通讯作者：
M. Bauer;B. Breier;J. Harding;J. Veldhuis;P. Gluckman
中科院分区：
文献类型：
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作者：
M. Bauer;B. Breier;J. Harding;J. Veldhuis;P. Gluckman
营养是产后生长轴的主要决定因素。然而，关于胎儿生长激素轴对营养限制的反应知之甚少。从妊娠第100天（任期= 147天），单胎母羊喂任意（对照组; n = 6）或25%的推荐能量和蛋白质的需求（限制; n = 7）。母羊和胎仔在第110天长期插管。在第120天，在6小时内以15分钟间隔采集配对的母体和胎儿血样。48小时后，给予胎儿20微克GRF推注（i. v.），收集样品48小时。营养不良组母儿GH水平均高于对照组（P < 0.05）。虽然母亲和胎儿的血浆GH曲线是独立的，但营养限制使母亲和胎儿的GH峰值和最低值均增加（P < 0.05），但峰/最低值比和脉冲数保持不变。解卷积分析表明，GH质量分泌每爆发是较高的营养限制的动物，而基础GH分泌和GH血清半衰期不受营养不良。母体和胎儿胰岛素样生长因子-I水平均降低（P < 0.01和P < 0.05），而胰岛素样生长因子-II浓度不受限饲的影响。在GRF激发后，来自限制性母体的胎儿具有较高的GH峰值浓度（P < 0.001），但校正后，[125 I]羊胎盘催乳素（[125 I]oPL）或[125 I]oGH与母体或胎儿肝微粒体膜制备物的特异性结合不受母体营养不良的影响。母体oPL浓度显示出相当大的短期波动，而胎儿oPL水平显示没有大的波动。在限制性动物中，平均母体oPL水平有升高趋势（P < 0.06），而胎儿oPL浓度有降低趋势（P < 0.06）。这些结果提供的证据表明，生长激素轴在子宫内的功能，并建议胎儿生长激素轴在胎儿适应营养限制发挥积极作用。
Nutrition is a major determinant of the somatotropic axis during postnatal life. However, little is known about the response of the fetal somatotropic axis to nutritional limitation. From day 100 of gestation (term = 147 days), singleton-bearing ewes were fed either ad libitum (control; n = 6) or 25% of the recommended energy and protein requirements (restricted; n = 7). Ewes and fetuses were chronically catheterized on day 110. On day 120, paired maternal and fetal blood samples were taken over a 6-h period at 15-min intervals. Forty-eight hours later, fetuses were given a 20-micrograms GRF bolus (i.v.), and samples were collected for 48 h. Undernourished mothers and fetuses had higher GH concentrations (P < 0.05). Although plasma GH profiles were independent in mothers and their fetuses, both maternal and fetal GH peak and nadir levels were increased (P < 0.05) by nutritional restriction, but the peak/nadir ratio and the number of pulses remained unaltered. Deconvolution analysis showed that the GH mass secreted per burst was higher in nutritionally restricted animals, whereas basal GH secretion and GH serum half-life were not influenced by undernutrition. Both maternal and fetal insulin-like growth factor-I levels were reduced (P < 0.01 and P < 0.05), whereas insulin-like growth factor-II concentrations were not influenced by the feed restriction. Fetuses from restricted mothers had higher peak GH concentrations after a GRF challenge (P < 0.001), but after correction The specific binding of [125I]ovine placental lactogen ([125I]oPL) or [125I]oGH to maternal or fetal hepatic microsomal membrane preparations was not changed by the maternal undernutrition. Maternal oPL concentrations showed considerable short term fluctuations, whereas fetal oPL levels revealed no major fluctuations. Mean maternal oPL levels tended (P < 0.06) to be elevated, whereas fetal oPL concentrations tended (P < 0.06) to be decreased in restricted animals. These results provide evidence that the somatotropic axis is functional in utero and suggest that the fetal somatotropic axis plays an active role during adaptation of the fetus to nutritional limitation.