Embryonic development of the porcine indifferent gonad and testis.

The early gonadal development in the pig from day 18 to day 36 post conception, when distinct testes were present in male embryos, has been studied. The development of the porcine gonad followed the general mammalian pattern. During testicular differentiation, the germ cells and the relevant somatic cells, the Sertoli cells, became enclosed in testicular cords, thus creating an intracordal germ cell compartment and an extracordal compartment. The development of conspicuous cell junctions and the production of a basal lamina were evident in the Sertoli cells during the early testis development. Their origin in this species remains unclear.