Insulin-like growth factor-I (IGF-I) and IGF-I receptor in human testis: an immunohistochemical study.

Using specific monoclonal antibodies, the authors studied the distribution of insulin growth factor-I (IGF-I) and its receptor in normal human testis by immunostaining techniques. IGF-I was preferentially localized in Sertoli cells. Less evident positivity was found in primary spermatocytes. In the interstitium some Leydig cells were positive for IGF-I. The major positivity for the IGF-I receptor was found in secondary spermatocytes and early spermatids, whereas Sertoli cells were less positive. An intense positivity was found in some Leydig cells.