Temporal expression of the KISS1/GPR54 system in goats' testes and epididymides and its spatial expression in pubertal goats.

Kisspeptin, encoded by the KISS1 gene, and its receptor GPR54 are essential in puberty onset and male fertility due to their central regulatory roles. However, the roles of KISS1/GPR54 in peripheral tissues remain unclear. This study aimed to investigate the temporal expression patterns of KISS1/GPR54 in goat testes and epididymides and its spatial expression patterns in pubertal goats. Immunohistochemical analysis revealed that kisspeptin/GPR54 were localized in Leydig, Sertoli, and germ cells of pubertal goats’ testis, as well as in principal and basal cells of the epididymis. RT-PCR revealed a marked variation in the KISS1/GPR54 expressions in the testes and epididymides from the age of first week to adulthood. KISS1 and GPR54 mRNA levels in testes decreased from the age of first week to two months and then increased from two months to puberty and adulthood. The KISS1 and GPR54 mRNA levels in Leydig cells decreased from the age of one week to two months and increased from two months to puberty, and then decreased from puberty to adulthood. Only GPR54 mRNA levels in the epididymides increased from the age of one week to two months and puberty, and then decreased from puberty to adulthood. RT-PCR analysis showed the different spatial expression patterns of KISS1/GPR54 in pubertal goat tissues. The KISS1 mRNA level was high in the hypothalamus, moderate in pancreas, liver, epididymis and testis; and low in the other tissues. The GPR54 expression was high in the pancreas and testis; moderate in pituitary, hypothalamus and mesenteric lymph node; and low in the other tissues. In conclusion, the KISS1/GPR54 system possessed distinct temporal expression profiles in goats’ testes and epididymides, as well as different spatial expression patterns in pubertal goat tissues, which implied the possible local role of this system in goats’ testes, epididymides, and other peripheral tissues.