Is there a mesonephric cell contribution to the gonadal primordium before sexual differentiation in humans?: An ultrastructural study.

Differentiation of the intermediate mesoderm involves a complex series of events that result in the formation of the rudiment of the entire adult renal system, gonads and gonoducts. This work, using light, transmission, and scanning electron microscopy describes in human embryos of different ages, the development and spatiotemporal organization of the mesonephric nephron, and the development of the gonadal primordium, with the purpose of knowing if and how these two blastemas contribute to the origin of the non germinal cell content of the gonad primordium. Our results show that between Carnegie stage 13 and 20, the mesonephric nephrons facing the gonadal area, are separated by a band of mesenchymal tissue from the gonad primordium and they retain their structural integrities at the level of epithelial wall and their basement membrane.