ANTI-MULLERIAN HORMONE IN EARLY HUMAN-DEVELOPMENT

Anti-Mullerian hormone (AMH) is a glycoprotein produced by immature Se rtoli cells and responsible for the regression of Mullerian ducts in m ale fetuses. The ontogeny of the hormone in early human development wa s investigated. While no detectable AMH could be found in female fetal serum, in males, the mean +/- S.E.M. AMH serum concentration was 40.5 +/- 3.9 ng/ml from 19 to 30 weeks (n = 13), and 28.4 +/- 6.1 ng/ml fr om 30 weeks to term (n = 9). The latter value is significantly differe nt from the mean AMH concentration in serum from boys aged 2 months to 2 years (43.1 +/- 3.7), suggesting that AMH production is sluggish du ring the perinatal period. The serum AMH concentration of a 46,XX male fetus was in the normal range for males. Using in situ hybridization, AMH transcripts were detected in the testicular tissue of all fetuses from 8 weeks onwards, but not in fetal ovaries nor in the yet undiffe rentiated gonadal tissue of a 7-week-old fetus bearing male-determinin g DNA sequences. Together, these data indicate that AMH is a reliable marker for the presence of functional testicular tissue and, as such, may be helpful for the diagnosis of fetal sex, particularly in the pre sence of sex chromosome abnormalities.