The transition from mitosis to meiosis is unique to germ cells. In murine embryonic ovaries and juvenile testes, retinoic acid (RA) induces meiosis via the stimulated by retinoic acid gene 8 (Stra8), but its molecular pathway requires elucidation. We present genetic evidence in vivo and in vitro that neuregulins (NRGs) are essential for the proliferation of spermatogonia and the initiation of m...

objective(s):this study was designed to investigate the effect of phaleria macrocarpa aqueous extract (pm) on spermatogenesis by observing the histological changes of testes in adult male rats. materials and methods: pm was prepared by boiling the dried slices of p. macrocarpa fruits followed by filtering, centrifugation and freeze-drying to obtain the powder form. eighteen sprague dawley adult...

BACKGROUND New research proposes the pluripotency of spermatogonial cells obtained from testis. These spermatogonia-derived stem cells are called embryonic stem-like cells that express embryonic stem cell markers and differentiate to the three germ layers. OBJECTIVES The aim of the present study was to generate embryonic stem-like cells from neonatal mouse testis. MATERIALS AND METHODS The ...

In the adult testis, the precise control of the self-renewing replication and differentiation of stem spermatogonia is fundamental to male fertility. Previous studies have shown that the replication of A single (A(s)) spermatogonia, a population that includes the stem cells, is maximal at stage I of the cycle of the rat seminiferous epithelium and minimal at stage VII, while the ratio of A-pair...

Spermatogenesis was histologically examined in non-breeding male of the naked mole rat (Heterocephalus glaber) using a light microscopy. Spermatogonia, spermatocytes and spermatids were confirmed in the seminiferous tubules. However, the spermatogenesis was disordered, and many spermatocytes and spermatids were sloughing. Sperms could not be seen in the lumen of the tubules. The characteristic ...

Spermatogenesis ranks among the most complex, yet least understood, developmental processes. The physiological principles that control male germ cell development in mammals are notoriously difficult to unravel, given the intricate anatomy and complex endo- and paracrinology of the testis. Accordingly, we lack a conceptual understanding of the basic signaling mechanisms within the testis, which ...

Stem cells support tissue maintenance by balancing self-renewal and differentiation. In mice, it is believed that a homogeneous stem cell population of single spermatogonia supports spermatogenesis, and that differentiation, which is accompanied by the formation of connected cells (cysts) of increasing length, is linear and nonreversible. We evaluated this model with the use of lineage analysis...

The expression of cyclins A, D1, D2 and E were examined immunohistochemically in 5 canine normal testes and 31 testicular tumors, including 14 seminomas, 11 Sertoli cell tumors and 6 Leydig cell tumors. In canine normal testes, cyclin A expression was detected in spermatogonia and primary spermatocytes. This suggests that A-type cyclins may play some role in canine spermatogenesis. Cyclin A exp...

Observations in patients with an activating mutation of fibroblast growth factor receptor 3 (FGFR3) suggest a role for FGFR3 signalling in promoting proliferation or survival of germ cells. In this study, we aimed to identify the FGFR3 subtype and the ontogeny of expression during human testis development and to ascertain whether FGFR3 signalling is linked to germ cell proliferation and the pat...