CART MRNA Expression And Its Effect On Estrogen In Hen Ovarian Follicles

CART (Cocaine- and Amphetamine-Regulated Transcript, CART), an endocrine endogenous neuropeptide, can play its biological roles in drug addiction, diet and obesity and endocrine by regulating the hypothalamic - pituitary - gonadal axis (adrenal axis, thyroid axis).The latest study found that CART has a negative regulation effect on follicular development and is associated with follicular atresia. Given the special role of CART in the process of follicle development and the laying hens ovarian developmental characteristics, in this study, laying hens were selected as the research objects, estrogen concentrations in follicular fluid of big, medium and small follicles were measured. At the molecular level, we used Real-time PCR to research the expression of CART mRNA in granulose cells and theca cells of different follicles, which were analyzed to clarify its expression pattern, to provide basis for further study of CART on laying hens. The results of the study were as follows:(1) Hormone assay showed that the concentration of estrogen in different developmental stages of follicle was carried out with the rising trend. The concentration of estrogen in large follicles in a diameter of>8 mm was significantly higher than small follicles and medium follicles(P< 0.05), and that in medium follicles in a diameter of 6-8 mm had no significant differences with small follicles in a diameter of 2-6 mm; (2) Real-time PCR results showed that the expression of CART mRNA in small follicles was significantly higher than that in large and medium follicles, and that in large and medium follicles was not significant (P> 0.05). (3) CART mRNA expression levels in large, medium and small follicles of laying hens were negatively correlated with the estrogen concentrations. The follicles with low CART mRNA expression levels secreted more estrogen and high CART mRNA expression levels with low estrogen secretion. By regulating estrogen synthesis, CART may thus affect the process of the growth of follicles, ovulation and follicular atresia.