The percentage bindings of testosterone, androstenedione and dehydroisoandrosterone were measured by equilibrium dialysis at the time of delivery in the plasma of 26 mothers and of their newborn infants. The values for all 3 androgens were in each instance much lower in the cord plasma than in the corresponding maternal plasma. Levels obtained for arterial and venous plasma from the cord showed no difference. Furthermore, the sex of the infants appeared to have no influence on either maternal or cord values. The percentage bindings of the 3 androgens in the mothers at the time of delivery were similar to those found during the last trimester of pregnancy. The concentrations of unbound testosterone, androstenedione and dehydroisoandrosterone were also calculated. The unbound testosterone was surprisingly elevated in newborn infants of both sexes, being about 3 times greater than that of the mothers. In contrast, the concentrations of unbound androstenedione and dehydroisoandrosterone were approximately 1/2 that of the mother at delivery. The consequences of these findings in relation to sex differentiation are discussed.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical