MULLERIAN-INHIBITING SUBSTANCE IN HUMANS - NORMAL LEVELS FROM INFANCYTO ADULTHOOD

Mullerian inhibiting substance (MIS) is a gonadal hormone synthesized by Sertoli cells of the testis and granulosa cells of the ovary. To fa cilitate the use of MIS for the evaluation of intersex disorders and a s a tumor marker in women with MIS-expressing ovarian tumors, we measu red MIS in 600 serum samples from males and females. These data show t hat mean MIS values for males rise rapidly during the first year of li fe and are highest during late infancy, then gradually decline until p uberty. In contrast, MIS values in females are lowest at birth and exh ibit a minimal increase throughout the prepubertal years. Whereas MIS is uniformly measurable in all prepubertal boys studied, it is undetec table in most prepubertal female subjects. These data reveal an easily discernible sexually dimorphic pattern of expression and confirm that MIS can be used as a testis-specific marker during infancy and early childhood. MIS values that are above the upper limits for females are discriminatory for the presence of testicular tissue or ovarian tumor, and those below the lower limits for males are consistent with dysgen etic or absent testes or the presence of ovarian tissue. These data wi ll enable normal and abnormal levels of MIS to be differentiated with higher precision and will facilitate the use of MIS in the management of gonadal disorders.