Developmental and Endocrine Regulation of Kisspeptin Expression in Mouse Leydig Cells

Kisspeptin, encoded by the Kiss1 gene, binds to a specific G protein-coupled receptor (kisspeptin1 receptor) to regulate the central reproductive axis. Kisspeptin has also been reported to be expressed in peripheral tissues, including the testes. However, factors regulating testicular kisspeptin and its role in reproduction are unknown. Our objective herein was to begin to address kisspeptin function in the testis. In particular, we sought to determine the level of kisspeptin in the testis in comparison with the brain and other tissues, how these levels change from the prepubertal period through sexual maturation, and the factors involved in kisspeptin regulation in the testis. Immunohistochemical analysis of testis sections using a validated kisspeptin antibody localized kisspeptin to the Leydig cells. Kisspeptin was not detected in germ cells or Sertoli cells within the seminiferous tubules at any developmental time period studied, from prepuberty to sexual maturation. A developmental time course of tes...