Primordial germ cells and gonadal development in the golden hamster.

We present results of a light and electron microscopical study of the developing hamster gonad. Two main problems have been examined: the source of somatic cells contributed to the developing gonad and the possible presence of nuage in germ cells. Nuage has been previously reported in hamster oocytes at meiosis; its possible presence at earlier stages and in male germ cells, especially meiotic spermatocytes, was investigated. The mesonephros was found to be the major source of somatic cells to the developing gonad, though a contribution from the coelomic epithelium could not be excluded, and interstitial tissue appeared to arise from mesenchymal cells. The presence of nuage associated with nuclear pores and mitochondria in hamster oocytes from Day 15 p.c. onwards has been confirmed. New findings are the association of nuage with intercellular bridges and its presence at earlier stages, including Day 8 p.c., and in male germ cells especially at the time of the entry to meiosis.