BACKGROUND: The @entity2339 is transiently activated during the postnatal months in @entity1 , a phenomenon termed "minipuberty" of infancy, when serum @entity251 (T) increases to pubertal levels. Despite high circulating T there are no signs of virilization. We hypothesize that free T as measured in saliva is low, which would explain the absence of virilization. METHODS: We measured serum total T and free T in saliva using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 30 @entity1 @entity1 , aged 1-6 months, and in 12 adolescents, aged 11-17 years. RESULTS: Total serum T in all @entity1 was, as expected, high (172    78 ng/dL) while salivary T was low (7.7    4 pg/mL or 0.45    0.20%). In contrast, salivary T in the adolescents was much higher (41    18 pg/mL or 1.3    0.36%) in relation to their total serum T (323    117 ng/dL). We provide for the first time reference data for salivary T in @entity1 . CONCLUSION: Measurement of salivary T by LC-MS/MS is a promising noninvasive technique to reflect free T in @entity1 . The low free T explains the absence of virilization. The minipuberty of infancy is more likely of intragonadal than peripheral significance.   .

Salivary XXXX during the Minipuberty of Infancy   .

@entity1 :: ('9606', 'Species') :: ['infants', 'boys', 'infant'] @entity251 :: ('MESH:D013739', 'Chemical') :: ['testosterone'] @entity2339 :: ('MESH:D007029', 'Disease') :: ['hypothalamic-pituitary-gonadal axis']
@entity251 :: (MESH:D013739,Chemical) :: ['Testosterone']
