IGSF1is expressed at high levels in testes and the pituitary, specifically in thyrotrophs, somatotrophs and lactotrophs. Its precise function within the context of the pituitary hormone axes and testicular function is still unknown. Igsf1 knock-out mice have central hypothyroidism, decreased pituitary TRH receptor 1 mRNA expression and impaired responsiveness to TRH compared to healthy littermates. This supports a role for impaired TRH action in the pathogenesis of the central CH. While mouse models have successfully recapitulated the IGSF1 deficiency central hypothyroidism phenotype, they lack the testicular enlargement phenotype. Although macroorchidism may results from IGSF1loss-of-function in testes, other Igsf1 knock-out animal models need to be explored in order to further elucidate its underlying pathophysiological mechanism.
IGSF1