title: Developmental changes of Müllerian and Wolffian ducts in domestic cat fetuses.
abstract: At 0.8 cm of crown-rump length (CRL) in sexually undifferentiated cat fetuses, the Wolffian duct is already observable on the ventro-lateral side of the mesonephros. At 1.2 cm CRL, the anlage of the Müllerian duct growing caudally in close parallel with the Wolffian duct was first observed. At 2.8 cm CRL in sexually differentiated fetuses, the Müllerian duct reached the urogenital sinus but remained indiscernible. Subsequently, at 3.2 cm CRL, regression of the upper part of the Müllerian duct was visible in males, while both ducts continued to grow in females. This suggests that the Müllerian inhibiting substance is produced before 3.2 cm CRL. At 7.0 cm CRL, male and female Wolffian ducts were reduced in diameter by about 50%, accompanied by involution of the mesonephros. Thereafter, the Wolffian duct was retained in the male; however, at 8.5 cm CRL in the female, the Wolffian duct was greatly reduced, by about 80% in diameter, then disappeared completely at 9.0 cm CRL.
authors.affiliation: Department of Laboratory Animal Science, School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, Japan.
authors.forename: Tomo
authors.initials: T
authors.lastname: Inomata
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Ninomiya
authors.forename: Katsuyasu
authors.initials: K
authors.lastname: Sakita
authors.forename: Naomi
authors.initials: N
authors.lastname: Kashiwazaki
authors.forename: Junya
authors.initials: J
authors.lastname: Ito
authors.forename: Makoto
authors.initials: M
authors.lastname: Ariga
authors.forename: Seiya
authors.initials: S
authors.lastname: Inoue
mesh_terms: D000818:Animals; D002415:Cats / Q000196:embryology*; D018568:Crown-Rump Length; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D008297:Male; D009095:Mullerian Ducts / Q000196:embryology*; D014928:Wolffian Ducts / Q000196:embryology*