Function Of BDNF And NT-4 In Secretion Of Gonadotrophins And Expression Of Their Receptors In The Reproductive Tissues In Rat

Mammalian reproductive function is regulated by the hypothalamus - pituitary -gonadal axis, and variety kinds of cytokines involved in the regulation ofreproductive activities. Brain-derived neurotrophic factor (BDNF) and neurotrophicfactor 4 (NT-4) are both neurotrophic factor family members, and many interests hasbeen focused on their effect in reproductive function in recent years. It has beenconfirmed that BDNF and NT-4 are both play important roles in folliculardevelopment, ovulation and ovarian hormone synthesis.In this research, we have detected (1) effects of exogenous BDNF and NT-4 ongonadotropin concentration in plasma; (2) effects of BDNF and NT-4 on expressionof gonadotropin receptor in rat reproductive organs; (3) effects of BDNF and NT-4on expression of the gonadotropin receptors and estrogen secretion of rat folliculargranulosa cells.Detection of gonadotropin concentrations in each treatment group in rat plasmawe found that concentrations of FSH and LH changed accompanied by exogenousinjection of BDNF and NT-4. BDNF and NT-4 can make plasma LH concentrationsdecreased, but the difference was not significant (p> 0.05)ï¼›BDNF injection decreaseplasma FSH concentrations with statistically significant(p <0.01).With BDNF and NT-4 recombinant protein injection, the rat reproductiveorgans gonadotropin receptor expression showing some regular changes. IncreasedBDNF and NT-4 concentration in the blood can make the LHR and FSHRexpression down-regulated on rat uterus and ovaries. In fallopian tube , LHR andFSHR expression showing a different way, which were up-regulated by the BDNFand NT-4. In vitro experiments showed that BDNF and NT-4 can also promote theexpression of LHR and FSHR in the rat follicular granulosa cells, and estrogensecreted by follicular granulosa cells were significantly enhanced by adding BDNFand NT-4 in cell culture system.We speculate that BDNF and NT-4 may play animportant role on ovarian function via improve the gonadotropin receptorsexpression level and enhanced granulosa cell hormone levels.Overall, BDNF and NT-4 may be involved in the hypothalamic - pituitary -gonadal regulation axis, and may change the concentration of plasma luteinizinghormone, gonadotropin receptor expression to regulate the reproductive system andparticipate in the regulation of mammalian reproductive regulation.