Localization And Abundance Of Ob-Rb In The Pig Hypothalamus,Pituitary And Ovary

According to the pig gene sequence published on Genebank, a pair of primers were designed and synthesized. Total RNA was isolated from the hypothalamus, pituitary, ovaries of Xiao Meishan pig by Trizole method. 343bp cDNA fragment was generated by reverse transcription-polymerase chain reaction (RT-PCR) and cloned into pGEM-T Easy Vector. The recombinant plasmid was identified by several kinds of specific methods and confirmed that the cDNA fragment sequence was full consistent with the published pig OB-Rb gene sequence on Genebank.By immunohistochemical method, we detected the distribution and localization of hypothalamus, pituitary and ovaries of Xiao Meishan pigs of newborn, 30, 60, 70, 90 days and Su Jiang pigs of newborn, 60, 120, 150, 180 days. The results showed that Ob-Rb positive particles were distributed in hypothalamus generally, especially arcuate nucleus; Ob-Rb positive particles of pituitary were concentrated into pituitarium anterius cells; and Ob-Rb positive particles of ovaries appeared in granular cell; granule cells of all types of follicles, but megagametocyte didn't discover the existence of the positive particles.In order to investigate quantitative expression of Ob-Rb mRNA in hypothalamus, pituitary, ovaries of Xiao Meishan porcine on newborn, 30, 60, 70, 90 days, Su Jiang porcine on newborn, 60, 120, 150, 180 days, immunohistochemical method was used. The results showed that the expression of Ob-Rb mRNA was the highest in ovaries, the next was in hypothalamus, the least was in pituitary. But on totally, there was no tissue specificness between pituitary and hypothalamus (p>0.05); in the same tissue but different period, Ob-Rb mRNA maintained high level during newborn, and then declined gradually, on 60 days it began to rise in Xiao Meishan porcine, on 70 days the expression reached to a peak; on 120 days it began to rise, when reached to 150 days it went up to a high level. But at the time of born in the two species, the expression of Ob-Rb mRNA of each tissue in Xiao Meishan were all higher than that of Su Jiang pigs(p>0.01).Leptin concentrations of plasma were measured by ELISA, the results showed that the level of Ob-Rb mRNA synchronized with the changes of leptin. Meanwhile, Plasma reproductive hormonal changes were detected in Xiao Meishan (from birth to 90 days) and Su Jiang (from birth to 180 days) gilts by radioimmunoassy. The results indicated that serum concentration of FSH,LH,E₂ were high at birth, significantly higher than that of other periods (p<0.01), then declined quickly and maintained at a low level. Concentration of FSH, LH, E₂, P rose quickly at puberty in Xiao Meishan and Su Jiang pigs.Our study explored the distribution and localization of Ob-Rb in hypothalamus, pituitary, ovaries, determined the express regularity between leptin and Ob-Rb mRNA in different period, and revealed the relation among several hormones in every period, all of above were good for studying biological effectiveness of leptin and the onset of puberty.