The number of germ cells in fry gonads was determined from histological sections sampled periodically over a 10-week post-hatching period. Several successive types of germ cells were identified: primordial germ cells (PGC), two kinds of gonocytes (G1 and G2) and all the stages of female meiotic prophase. The mean diameters are shown in table 1. The number of germ cells increased regularly from ...

BACKGROUND Cadmium (Cd) is a common environmental pollutant and a major constituent of tobacco smoke. Adverse effects of this heavy metal on reproductive function have been identified in adults; however, no studies have examined its effects on human reproductive organs during development. OBJECTIVES Using our previously developed organ culture system, we investigated the effects of cadmium ch...

Mixed gonadal dysgenesis (MGD) is an abnormal sexual differentiation syndrome usually presenting with ambiguous genitalia. Karyotype analysis is one of the essential components in the diagnosis of MGD and is conventionally done with peripheral lymphocytes by the G-banding technique. It is speculated that this conventional karyotype analysis has limitations since there are often difference in go...

In many animals, primordial germ cells (PGCs) migrate into developing gonads. There, they proliferate and differentiate into female and male germ stem cells (GSCs), oogonia and spermatogonia, respectively. Few studies have focused on the molecular mechanisms underlying the development of GSC sex determination. Here, we investigated the expression of the transcription factor Dmrt1 and a phosphor...

The chicken embryo represents a suitable model for studying vertebrate sex determination and gonadal sex differentiation. While the basic mechanism of sex determination in birds is still unknown, gonadal morphogenesis is very similar to that in mammals, and most of the genes implicated in mammalian sex determination have avian homologues. However, in the chicken embryo, these genes show some in...

Since sturgeons have no external sexual dimorphism and there are no external markers to determine sex, internal examination of the gonads should be used to sex identification. The present study describes the biopsy method and histological observations of the gonads of great sturgeon (Huso huso) in both sexes at different age classes. Sex and maturity stages of 226 great sturgeons were identifie...