LEYDIG INSULIN-LIKE HORMONE, GUBERNACULAR DEVELOPMENT AND TESTICULAR DESCENT

Purpose: Testicular descent is controlled by 2 morphological and hormonal steps. Transabdominal testicular descent is mediated by gubernacular swelling and regression of the cranial suspensory ligament. Mullerian inhibiting substance (MIS) has been proposed to stimulate the swelling but this remains controversial. Recently, a mouse mutant for Leydig insulin-like hormone (Insl3) was found to have undescended testis and deficient gubernaculum. We examine the testicular position of Insl3 mutant mice and the development of gubernacula.Materials and Methods: Mice with Insl3 homozygotes (−/−), heterozygotes (+/−) and wild-types (+/+) were examined at embryonic day 16.5 and birth. Macroscopic dissections and measurements of the testicular position, as well as microscopic analysis (hematoxylin and eosin, and Masson’s trichrome) were performed.Results: Of the mice 11 Insl3 homozygote males had significantly impaired testicular descent at embryonic day 16.5 and birth (p <0.01), and the cord was thin and elongated, ...