Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The development of the prostate in male rodents, which involves complex epithelial-mesenchymal interactions between the urogenital sinus epithelium (UGE) and the urogenital sinus mesenchyme (UGM), has been deeply studied. In females, however, this process is not very clear. In this study, the postnatal development of the prostate in female Mongolian gerbils employing three-dimensional (3D) reconstructions, histochemical, and immunohistochemical techniques was characterized. It was observed that prostatic branching and differentiation in females was induced by a single mesenchyme localized at a ventrolateral position, which was named as ventrolateral mesenchyme (VLM); furthermore, the canalization of solid buds began on the third postnatal day (P3) and the branching morphogenesis on P5. We observed secretions in the acini at the end of the first month, and, on P45, the acini were completely differentiated. The strong cell proliferation phase in the first week coincided with the mesenchymal expression of estrogen receptor 1 (ESR1). The expression of androgen receptor (AR) paralleled cell differentiation, and, on P30, immunolabelling with p63 was restricted to basal cells. This study serves as a baseline parameter for future research on disruptions that could affect the development of the female prostate. (C) 2016 Wiley Periodicals, Inc.79 438446Sao Paulo Research Foundation (FAPESP) [2013/15939-0, 2013/16443-9]Brazilian National Research and Development Council (CNPq) [301596/2011-5]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)