Abstract:

Objective To investigate the changes of expression of Ghrelin and peptide YY (PYY) mRNA and protein in gastrointestinal tract and their receptors mRNA in hypothalamus in neonatal rats, and explore their relationship with the maturity degree of gastrointestinal tract. Methods Ten neonatal rats of 0 day old (day 0 rats) and 10 neonatal rats of 7 days old (day 7 rats) were selected, and Real-time PCR and immunohistochemical staining were employed to detect the expression of Ghrelin mRNA and protein in gastric fundus tissues, PYY mRNA and protein in colon tissues and Ghrelin and PYY receptors mRNA in hypothalamus. Results The expression of Ghrelin mRNA in gastric fundus tissues of day 0 rats was significantly higher than that of day 7 rats (P<0.05), while the expression of PYY mRNA in colon tissues of day 0 rats was significantly lower than that of day 7 rats (P<0.01). The expression of Ghrelin and PYY protein in gastrointestinal tract tissues of day 0 rats was significantly higher than that of day 0 rats (P<0.05). There was no significant difference in the expression of Ghrelin and PYY receptors mRNA in hypothalamus between day 0 rats and day 7 rats (P>0.05). Conclusion The levels of Ghrelin and PYY synthesis and secretion may increase in immature gastrointestinal tract, which may promote the development and maturation of gastrointestinal tract. The unparalleled expression of PYY mRNA and protein indicates the diversity in the regulation of gene expression.

Key words: peptide YY, Ghrelin, neonatal rat, gastrointestinal tract, receptor