The genus Acipenser as a model for vertebrate urogenital development: the müllerian duct

Abstract

The development of the müllerian duct was studied in a total of 85 specimens of Acipenser ruthenus and Acipenser baeri in the period from 7 days after hatching through 5 years of age. Normal histology on serial sections, transmission and scanning electron microscopy and bromodeoxyuridine immunohistochemistry were applied. In Acipenser, the primary set of opisthonephric nephrons possess short nephrostomial tubules with well-developed nephrostomes. Proliferating cells from the lateral side of the slightly protruding nephrostomial lips spread out over the ceolomic surface, replace here the flat mesothelium of lateral plate origin and establish the infundibular field, consisting of cuboidal or columnar cells. At about 28 days after hatching, the primordium of the müllerian infundibulum becomes visible in the form of a pocket-like invagination within the infundibular field. This invagination is found coexisting with and located laterally to the line of intact nephrostomes. The müllerian infundibulum, therefore, does not represent the homologon of a nephrostome itself, but must be regarded as a separate and secondary structure. The müllerian duct proper has its origin in cells from the bottom of the infundibular pocket. These cells grow as a tubule with a solid tip in the caudal direction, paralleling the wolffian duct, but without a contribution of cells from the latter. In Acipenser, a müllerian duct is present also in the adult male. In males as in females, the caudal extremity of the müllerian duct generally divides into two to three smaller terminals which end in the wolffian duct at different levels, but always cranial to the urogenital sinus. In most indifferent animals and in all males of this study, the tips of the müllerian terminals are closed and covered by a thin layer of wolffian epithelium. In adult females, the müllerian ducts end with open terminals. In both sexes, the adult müllerian duct is lined by a pseudostratified columnar epithelium, consisting of ciliated, non-ciliated and basal free cells.

Postnatal development of the reproductive system in the grey short-tailed opossum, Monodelphis domestica

“…Bar, 250 mm this is supported by detection of the enzyme 3b-HSD in Leydig cells at day 16 (Xie et al 1998). A recent paper on the ray-finned chondrostean fish, Acipenser, has elucidated the evolution and development of the müllerian duct (Wrobel 2003).…”

Expression profile and estrogenic regulation of anti‐Müllerian hormone during gonadal development in pejerrey Odontesthes bonariensis, a teleost fish with strong temperature‐dependent sex determination

“…Among fishes, only early evolved ray-finned species such as the sturgeons (Acipenser spp.) present Mü llerian ducts, but these structures do not regress completely in males as they do in mammals (Wrobel, 2003). On the other hand, most teleost fish do not have Mü llerian ducts but they do possess an amh homologue that usually shows a sexually dimorphic expression profiles during gonadal sex differentiation and/or adulthood.…”

Elevated <i>amh</i> Gene Expression in the Brain of Male Tilapia <i>(Oreochromis niloticus) </i>during Testis Differentiation

“…Mülle-rian ducts have only been described in basal ray-fin fish such as sturgeons and they do not degenerate [Wrobel, 2003]. Amh was initially expressed in both sexes and then became dimorphic, expressed strongly in the pre-Sertoli cells of testes, as sex differentiation progressed in the Japanese flounder [Yoshinaga et al, 2004], Nile tilapia [Ijiri et al, 2008] and rainbow trout [Vizziano et al, 2008].…”