Mullerian ducts

In the early mammalian female embryo the absence of the Mullerian inhibitory substance MIS permits continuing development of the Mullerian duct, while the absence of testosterone permits the Wolffian duct to degenerate. However, positive developmental signals are also required. Among these is the protein Wnt-4, a member of a large family of locally acting signal molecules (Section 4). Wnt-4 may be needed both for oocyte development and for further suppression of male development.261... 

The Sertoli cells in the testis synthesize and secrete a variety of active proteins, including mullerian duct inhibitory factor, inhibin, and activin. As in the ovary, inhibin and activin appear to be the product of three genes that produce a common alpha subunit and two beta subunits, A and B. 

Biason-Lauber A, Konrad D, Navratil F, Schoenle EJ (2004) A WNT4 mutation associated with Mullerian-duct regression and virilization in a 46,XX woman. N Engl J Med, 351(8) 792-798. 

MIS (Mullerian inhibiting substance) or AMH (anti-Mtillerian hormone) Regression of the Mullerian duct... 

After the fetal gonads are converted into testes by SRY, testosterone and Miillerian-inhibiting substance (MIS) control subsequent sexual differentiation. MIS causes the regression of the Mullerian duct, which would otherwise develop into female genital tracts. Testosterone promotes the development of the Wolffian duct into male internal genitalia, including epididymis, vas deferens, and seminal vesicles. 

G. gallus since El PSM, somites, at E2.1 telencephalon, olfactory placodes at 7.5 Mullerian duct Smith et al., 2002... 

Fig. 3. Schematic representation of the fetal development of characteristically male and female intraabdominal and external genital organs in eutherian mammals. (A) Top frame primitive indifferent (ambisexual) organs appearing the same in normal genetic males and females before the onset of hormone production by the fetal testis in males, and at approximately the same time of development in females. (A) Lower frame derivation of male and female structures from the Wolffian and Mullerian ducts and from the urogenital structure. (B) Upper frame primitive ambisexual external genital primordia (anlagen). (B) Lower freune differentiation of normal male and female external genitalia. Reproduced, with permission, from Griffin and Wilson (34).

The fetal testis induces a male type of phenotypic sex development by virtue of producing two sorts of hormones. The first of these is the androgen testosterone, which triggers the formation of male structures from the Wolffian duct, the urogenital sinus, and the external genital primordia, via mechanisms considered below. The second type of fetal testicular hormone is a macromolecule, apparently a glycoprotein, that evokes involution of the Mullerian duct during normal male sex differentiation. 

Congenital malformations of the uterus, also termed Mullerian duct anomalies (MDA) are an uncommon, but often treatable cause of infertility. Estimates of its frequency vary widely owing to different patient... 

---