High serum concentrations of dimeric inhibins A and B in normal newborn girls

OBJECTIVE: To establish the serum pattern of dimeric inhibins in normal girls during the newborn period and to examine its relationship with the postnatal gonadotropic surge. DESIGN: Retrospective study. SETTING; Division of endocrinology of a children's hospital. PATIENT(S): Thirty-one girls 4 to 65 days of age. MAIN OUTCOME MEASURE(S): Serum levels of FSH, LH, and inhibin A and B. RESULT(S): High serum concentrations of both dimeric inhibins were detected during the first weeks of life. Concentrations tended to decrease through the second month of age. Inhibin A and B concentrations positively correlated with age only during the first 2 weeks of life (r =.57, P<.05 and r =.70, P<.01, respectively). Inhibin A and B were positively and significantly correlated with LH (r =.57, P<.05 and r =.52, P<.05, respectively) and with each other (r =.68, P<.0001). No correlation was found between dimeric inhibins and FSH. CONCLUSION(S): The high inhibin concentrations observed in newborn girls, which indicate advanced follicular development and granulosa cell differentiation, may be useful markers for congenital gonadal disorders.