Yonekura S, Kitade K, Furukawa G, Takahashi K, Katsumata N, Katoh K, Obara Y
Department of Animal Physiology, Graduate School of Agricultural Science, Tohoku University, Amamiyamachi, Sendai 981-8555, Japan.
Domest Anim Endocrinol. 2002 Mar;22(1):25-35. doi: 10.1016/s0739-7240(01)00114-x.
In order to know the effects of weaning and volatile fatty acid feeding on gastric leptin expression, we investigated the expression of leptin and CCK receptor mRNA in the bovine rumen, abomasum and duodenum using RT-PCR in 3-week-old pre-weaning, 13-week-old post-weaning and adult animals. Leptin mRNA was expressed in the rumen and abomasum of 3-week-old pre-weaning animals, but it was abolished in 13-week-old and adult animals. In the duodenum, leptin expression was observed in the 3-, 13-week-old and adult animals. In the rumen, CCK(A) receptor mRNA was expressed in 3-week-old animals, but not in 13-week-old and adult animals. In the abomasum, CCK(B) receptor expression gradually decreased from 3-week-old to adult animals. Expression of CCK(B) receptor and of CCK(A) receptor was slight in the rumen and abomasum, respectively. In the next study, we examined the effect of weaning of 6 weeks or non-weaning (fed on milk replacer alone (milk) or milk replacer with volatile fatty acids (milk+VFA) until 13 weeks old) on leptin mRNA expression in the rumen and abomasum. In 13-week-old calf rumen and abomasum, leptin mRNA expression was detected in non-weaning milk-fed animals at 13 weeks old, although it was not observed in weaning and non-weaned milk+VFA-fed animals. The change in CCK(A) receptor expression in the rumen was similar to those of leptin mRNA expression. CCK(B) receptor transcription in the abomasum of milk-fed animals was higher than that of the weaning and milk+VFA-fed animals. These results indicate that leptin expression is coincident with CCK receptor expression in calf stomachs, and that leptin and CCK receptor mRNA expression are affected by the change in the physiological status brought about by weaning and VFA feeding.
为了解断奶和挥发性脂肪酸喂养对胃瘦素表达的影响，我们运用逆转录聚合酶链反应（RT-PCR），对3周龄断奶前、13周龄断奶后及成年动物的瘤胃、皱胃和十二指肠中瘦素及胆囊收缩素（CCK）受体mRNA的表达进行了研究。瘦素mRNA在3周龄断奶前动物的瘤胃和皱胃中表达，但在13周龄及成年动物中消失。在十二指肠中，3周龄、13周龄及成年动物均有瘦素表达。在瘤胃中，CCK(A)受体mRNA在3周龄动物中表达，而在13周龄及成年动物中不表达。在皱胃中，CCK(B)受体表达从3周龄动物到成年动物逐渐降低。CCK(B)受体和CCK(A)受体分别在瘤胃和皱胃中表达轻微。在接下来的研究中，我们研究了6周龄断奶或未断奶（仅用代乳粉（牛奶）或添加挥发性脂肪酸的代乳粉（牛奶+VFA）喂养至13周龄）对瘤胃和皱胃中瘦素mRNA表达的影响。在13周龄犊牛的瘤胃和皱胃中，13周龄未断奶且喂牛奶的动物中检测到瘦素mRNA表达，而在断奶及未断奶且喂牛奶+VFA的动物中未观察到。瘤胃中CCK(A)受体表达的变化与瘦素mRNA表达的变化相似。喂牛奶动物皱胃中CCK(B)受体的转录高于断奶及喂牛奶+VFA动物。这些结果表明，瘦素表达与犊牛胃中CCK受体表达一致，且断奶和VFA喂养引起的生理状态变化会影响瘦素和CCK受体mRNA的表达。
