Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719 Olsztyn-Kortowo, Poland.
Anim Reprod Sci. 2010 Jan;117(1-2):111-8. doi: 10.1016/j.anireprosci.2009.03.007. Epub 2009 Mar 25.
Orexin A and B, also termed hypocretin 1 and 2, are associated with the stimulation of food intake and arousal. The biological actions of the hormones are mediated via two distinct G protein-coupled receptors, termed orexin receptor 1 (OX1R) and orexin receptor 2 (OX2R). OX1R is selective for orexin A and OX2R binds orexin A and orexin B with similar affinity. The present study analyzed mRNA and protein expressions of OX1R and OX2R in adenohypophysis (AP) and neurohypophysis (NP) of cycling pigs. The tissue samples were harvested on days 2-3, 10-12, 14-16, and 17-19 of the oestrous cycle. Using quantitative real-time PCR higher OX1R gene expression was detected in AP on days 2-3 relative to days 10-12, 14-16 and 17-19 (p<0.05). In NP the OX1R mRNA level was elevated on days 10-12 compared to the remaining stages (p<0.05). OX2R gene expression in AP was the lowest on days 10-12 (p<0.05 compared to days 2-3 and 17-19) and the expression peak occurred on days 17-19 (p<0.05 vs. the all studied stages). In NP the highest (p<0.05) expression of OX2R mRNA was noted on days 17-19 in relation to the remaining periods. OX1R protein content in AP was greatest on days 10-12 (p<0.05), whereas in NP it was greatest on days 2-3 and 14-16 (p<0.05 vs. days 10-12 and 17-19). In both cases the lowest OX1R protein expression was observed during follicular phase (p<0.05 in relation to three remaining studied stages). OX2R protein in AP was lower (p<0.05) on days 2-3 and 14-16 compared to days 10-12 and 17-19. In NP the lowest (p<0.05) expression of this protein was on days 17-19 and the highest on days 10-12 (p<0.05 compared to days 2-3 and 17-19). In summary, the present findings provide the first evidence that OX1R and OX2R mRNAs and proteins occur in the pituitary of the pig and indicate the dependence of orexin receptor expression on the endocrine reproductive state.
食欲肽 A 和 B，也称为下丘脑泌素 1 和 2，与食物摄入和觉醒的刺激有关。这些激素的生物学作用是通过两种不同的 G 蛋白偶联受体介导的，分别称为食欲肽受体 1（OX1R）和食欲肽受体 2（OX2R）。OX1R 对食欲肽 A 具有选择性，而 OX2R 则以相似的亲和力结合食欲肽 A 和食欲肽 B。本研究分析了发情周期中循环猪的腺垂体（AP）和神经垂体（NP）中 OX1R 和 OX2R 的 mRNA 和蛋白表达。组织样本分别于发情周期的第 2-3、10-12、14-16 和 17-19 天采集。使用定量实时 PCR，发现在第 2-3 天，AP 中 OX1R 基因的表达高于第 10-12、14-16 和 17-19 天（p<0.05）。在 NP 中，OX1R mRNA 水平在第 10-12 天高于其他阶段（p<0.05）。AP 中 OX2R 基因的表达在第 10-12 天最低（p<0.05 与第 2-3 和 17-19 天相比），表达高峰出现在第 17-19 天（p<0.05 与所有研究阶段相比）。在 NP 中，OX2R mRNA 的表达最高（p<0.05）出现在第 17-19 天，与其他阶段相比。AP 中 OX1R 蛋白含量在第 10-12 天最高（p<0.05），而在 NP 中，在第 2-3 和 14-16 天最高（p<0.05 与第 10-12 和 17-19 天相比）。在这两种情况下，在卵泡期观察到最低的 OX1R 蛋白表达（p<0.05 与其余三个研究阶段相比）。AP 中的 OX2R 蛋白在第 2-3 和 14-16 天低于第 10-12 和 17-19 天（p<0.05）。在 NP 中，这种蛋白的表达最低（p<0.05）出现在第 17-19 天，最高出现在第 10-12 天（p<0.05 与第 2-3 和 17-19 天相比）。总之，本研究结果首次提供了证据，表明食欲肽 A 和 B 的 mRNA 和蛋白质存在于猪的垂体中，并表明食欲肽受体表达依赖于内分泌生殖状态。
