[cDNA cloning of human testicular follicle-stimulating hormone receptor and analysis of its in vitro function]

A cDNA was cloned from human testis cDNA library by the use of rat FSH receptor cDNA as a probe. Transformation of 293 cells with the cloned cDNA led to expression of specific human FSH binding sites with high affinity (Kd: 1.5 x 10(-9) M), ligand dose-dependent production of cAMP and promotion of phosphatidyl inositol turnover, indicating that the cloned cDNA must encode a human FSH receptor. Northern blot analysis using human ovarian tissues revealed a high expression of mRNA at the stage of early follicular phase, but not luteal phase. Cross-linking of ligand with the expressed human FSH receptor showed that the molecular mass of the receptor should be 76 kDa, consistent with the estimated size of deduced amino acid sequence from the cloned cDNA. A polymorphism was found at 680th amino acid Ser or Asn, in the C-terminal region of the receptor although the influence of this difference upon the receptor function was not determined obviously in this study yet. The incidence of the polymorphism in the C-terminal region was not significantly correlated to the reproductive failures in 70 female cases of endometriosis, hyperprolactinemia, amenorrhea, PCOD or POF. However, elucidation of the structure and function in human FSH receptor using the cDNA will be applicable to diagnosis of some clinical cases associated with abnormal FSH receptor gene in the future.