[Relationship between Ghrelin and growth hormone secretagogue receptor expression and catch-up growth in rats with intrauterine growth restriction].

Objective: To study the relationship between Ghrelin and growth hormone secretagogue receptor (GHSR) expression and the catch-up growth in rats with intrauterine growth restriction (IUGR).

Methods: The rat model of IUGR was established by food restriction during pregnancy. The small for gestational age (SGA) and appropriate for gestational age (AGA) rat pups from the pregnant rats were used as the experimental group. The AGA rat pups from the pregnant rats without food restriction served as the control group. The samples from the stomach fundus and hypothalamus were taken postnatal days 0, 20 and 40. Ghrelin mRNA and GHSR mRNA expression were determined by real-time fluorescence quantitative PCR (real-time FQ-PCR). Ghrelin protein and GHSR protein expression were examined by immunohistochemistry (IHC).

Results: At postnatal day 0, both Gherlin mRNA and protein levels in the stomach fundus were significantly higher, while GHSR mRNA expression in the hypothalamus were significantly lower in SGA rats from food restriction group than those in AGA rats from restriction and control groups. At postnatal day 20, the ghrelin protein expression in the stomach of fundus, and GHSR mRNA and protein expression in the hypothalamus in SGA catch-up rats were significantly higher than those in SGA non-catch-up growth rats and AGA rats from the control group. At postnatal day 40, there were no significant differences among SGA catch-up growth rats, SGA non-catch-up growth rats and normal AGA rats.

Conclusions: Ghrelin-GHSR might be involved in the physiological regulation and pathological process in IUGR rats. It is also possibly involved in the regulation of catch-up growth in the early life of SGA rats.