Kaminski T, Smolinska N, Gajewska A, Siawrys G, Okrasa S, Kochman K, Przala J
Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, Poland.
J Physiol Pharmacol. 2006 Mar;57(1):95-108.
Leptin is a polypeptide that plays a key role in the regulation of energy homeostasis and is also linked, among others, to mechanisms controlling reproductive processes. Data concerning the involvement of leptin in controlling reproductive functions at the level of hypothalamus and pituitary in the pig are limited. Therefore, in the present study, an expression of genes coding for leptin and long-form leptin receptor (Ob-Rb) was determined by a semiquantitative reverse transcription polymerase chain reaction (RT-PCR) in the discrete areas of porcine hypothalamus (medial basal hypothalamus - MBH, preoptic area - POA, stalk median eminence - SME) and pituitary (anterior - AP and posterior/neural - NP parts) during the luteal phase of the cycle (days 10-12 and 14-16) and two early stages of pregnancy (days 14-16 and 30-32). Leptin gene expression in MBH was found to be higher in the mid- than in the late-luteal phase, whereas in other structures studied it remained unchanged during these periods. More pronounced differences were noted in expression of Ob-Rb gene, which was increased in MBH, AP and NP during the late-luteal phase in comparison to the mid-luteal one, whilst the relationship in the POA was reversed. In turn, during pregnancy, leptin gene expression in all tested areas of hypothalamus as well as Ob-Rb mRNA content in MBH were higher on days 30-32 than on days 14-16. In contrast, in the anterior pituitary, Ob-Rb gene expression was more pronounced on days 14-16 than during later stage of pregnancy. Comparison of leptin and Ob-Rb mRNA content in studied structures between the mid-luteal phase and days 14-16 of pregnancy revealed inhibition of leptin gene expression in almost all examined tissues (MBH, POA, SME, NP) during early pregnancy whereas Ob-Rb gene expression was inhibited in POA but stimulated in both parts of the pituitary during this stage. In summary, obtained results suggest an involvement of leptin in the regulation of hypothalamic-pituitary axis activity during both the luteal phase of the cycle and early pregnancy in pigs.
瘦素是一种多肽，在能量稳态调节中起关键作用，并且还与控制生殖过程的机制等相关。关于瘦素在猪的下丘脑和垂体水平上参与控制生殖功能的数据有限。因此，在本研究中，通过半定量逆转录聚合酶链反应（RT-PCR）测定了猪下丘脑离散区域（内侧基底部下丘脑 - MBH、视前区 - POA、柄正中隆起 - SME）和垂体（前部 - AP和后部/神经部 - NP）在发情周期黄体期（第10 - 12天和14 - 16天）以及妊娠两个早期阶段（第14 - 16天和30 - 32天）中编码瘦素和长型瘦素受体（Ob-Rb）的基因表达。发现MBH中瘦素基因表达在黄体中期高于黄体后期，而在研究的其他结构中，这些时期该基因表达保持不变。在Ob-Rb基因表达上观察到更明显的差异，与黄体中期相比，黄体后期MBH、AP和NP中的Ob-Rb基因表达增加，而POA中的情况则相反。反过来，在妊娠期间，下丘脑所有测试区域的瘦素基因表达以及MBH中Ob-Rb mRNA含量在第30 - 32天高于第14 - 16天。相反，在前垂体中，Ob-Rb基因表达在第14 - 16天比妊娠后期更明显。比较黄体中期和妊娠第14 - 16天研究结构中瘦素和Ob-Rb mRNA含量发现，妊娠早期几乎所有检查组织（MBH、POA、SME、NP）中的瘦素基因表达均受到抑制，而在此阶段POA中的Ob-Rb基因表达受到抑制，但垂体两部分中的Ob-Rb基因表达均受到刺激。总之，获得的结果表明瘦素参与了猪发情周期黄体期和妊娠早期下丘脑 - 垂体轴活动的调节。
