Regulação de secreção de FSH em reprodutores de frango

Synthesis and secretion of LH and FSH takes place in the gonadotropes of the pituitary gland (adenohypophysis). The hypothalamus, in turn, controls the secretion of gonadotropins by the pulsatile secretion of gonadotropin releasing hormone. Therefore, the neuroendocrine linkage of the hypothalamic-pituitarygonadal axis provides an integrated system responsible for proper reproductive performance, including gamete development and sex steroids secretion. In broilers there is a lack of synchrony between LH and FSH pulses, and gonadotrophs reside in separate cells within the pituitary gland, suggesting that in the adult male fowl LH and FSH secretion are regulated independently. Modern male broiler breeders (selected for increased growth rate) fail to maintain testis size and semen production after 25 weeks of age. Testis size closely follows changes in FSH concentrations, suggesting that circulating FSH levels are a very good indicator of testis function in mature broiler breeder. Although cGnRH-I is believed to be the prime regulator of gonadotropin release in male birds, the role of other GnRH isoforms in the regulation of FSH remains unclear. Therefore, there is critical need to further evaluate the actual regulation of FSH, and the underlying effect FSH on testicular function in mature broilers.