Secretion pattern of growth hormone, prolactin, insulin and insulin-like growth factor-1 in the periparturient sow depending on the metabolic state during lactation
Secretion pattern of growth hormone, prolactin, insulin and insulin-like growth factor-1 in the periparturient sow depending on the metabolic state during lactation
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DOI：
10.1017/s1357729800010110
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发表时间：
1998-10-01
期刊：
影响因子：
--
通讯作者：
Schams, D
中科院分区：
文献类型：
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作者：
Kraetzl, WD;Zimmer, C;Schams, D
本研究的目的是调查在为期4周的哺乳期内不同能量水平对代谢激素生长激素（GH），催乳素，胰岛素和胰岛素样生长因子-1（IGF-1）的调节的影响。共21头杂交母猪（德国长白猪×杜洛克猪）从分娩前3周至断奶后2周每天采血，每周窗口采样（每20 min，持续10 h）。19头母猪在妊娠后期饲喂2.8 kg饲料，哺乳期饲喂5.0 kg饲料，断奶后每天饲喂2.8 kg饲料，2头母猪在哺乳期饲喂限制水平（3.0 kg）的饲料。在19头母猪中，通过将不同数量的哺乳仔猪分配给各自的母猪，诱导了不同的能量平衡。一组母猪哺乳7头仔猪并作为对照（C;数量= 7），另一组哺乳10至12头仔猪并能量不足（D）。研究结束后，根据从分娩至断奶期间的窝重增加，将缺乏组母猪分为Io至（D-L;数量= 6）或高（D-H;数量= 6）窝重增加。在哺乳期，D-H母猪的体重比C母猪减少，并且在早晨饲喂前具有较低的葡萄糖和较高的非酯化脂肪酸水平。GH和催乳素在分娩前后增加，并且它们在哺乳期间的分泌特征被频繁的吸吮刺激改变，由此仔猪对它们的母体的访问不受控制。在哺乳期间，GH和催乳素在D-H母猪中最高。结果表明，不仅生长激素，但也催乳素营养分配到乳腺的哺乳期开始前，并尽量减少负面影响的能量平衡的可能作用。此外，胰岛素和IGF-I增加分娩前后在所有母猪。胰岛素在饲喂前和饲喂后均较高，且C组和D-L组的水平最高。胰岛素和IGF-1的调节模式表明，泌乳母猪能够从身体储备中动员足够的能量，以防止代谢紊乱，即使在能量供应不足的时期。这与奶牛中的调节相反，在奶牛中，负能量平衡与高产奶量阶段期间的严重葡萄糖不足相结合，这导致胰岛素和IGF-1水平降低。在母猪中，食物中的葡萄糖摄入量也满足了哺乳期能量摄入不足期间代谢途径的葡萄糖需求。因此，在母猪中，在营养能量缺乏的状态期间，IGF-1可以通过肝脏中的GH受体通过增加的GH水平来刺激，并且母猪可以比奶牛更好地补偿缺乏的代谢状态的事实也反映在相应的内分泌学中。
The aim of the study was to investigate the influence of different energy levels during a 4-week lactation on the regulation of the metabolic hormones somatotropin (GH), prolactin, insulin and insulin-like growth factor-1 (IGF-1). A total of 21 crossbred sows (German Landrace X Duroc) were cannulated for daily blood collection from 3 weeks before parturition until 2 weeks after weaning and for weekly window sampling (every 20 min for 10 h). Nineteen sows were given 2.8 kg food during late gestation, 5.0 kg food during lactation and 2.8 kg food per day after weaning and two sows were given food at a restricted level (3.0 kg) during lactation. In the 19 sows, the different energy balance was induced by allocation of different numbers of sucking piglets to the respective sows. One group of sows suckled seven piglets and served as a control (C; no. = 7) and another group suckled 10 to 12 piglets and was energy deficient (D). After the study, the sows of the deficient group were, based on their litter weight gain from parturition until weaning divided into Io to (D-L; no. = 6) or high (D-H; no. = 6) litter weight gain. The D-H sows lost move body weight during lactation than C and had lower glucose and higher nonesterified fatty acids levels before morning feeding. GH and prolactin increased around parturition and their secretory profiles during lactation were altered by the frequent sucking stimulus, whereby the access of the piglets to their dams was not controlled During lactation, GH and prolactin were highest in D-H sows. The results suggest a possible role of not only GH but also of prolactin in nutrient partitioning to the mammary gland just before the start of lactation and for minimizing the adverse effects of a negative energy balance. Furthermore, insulin and IGF-I increased around parturition in all sows. Insulin was higher before and after feeding and the highest levels were found in C and D-L sows. The regulation patterns of insulin and IGF-1 indicate that the lactating sow is able to mobilize enough energy from body reserves to prevent metabolic disorders, even during a period with deficient energy supply. This is contrary to the regulation in the dairy cow, where the negative energy balance is coupled with a severe glucose deficit during phases of high milk yield, which causes decreased levels of insulin and IGF-1. In the sow, the glucose intake with the food meets the glucose requirement for metabolic pathways also during a deficient lactational energy intake. Therefore, in sows IGF-1 can be stimulated by increased GH levels via the GH receptor in the liver during a state of nutritional energy deficiency and the fact that sows can compensate a deficient metabolic state much better than cows is also reflected in the respective endocrinology.