Testicular and adrenal androgens and their binding to plasma proteins in the perinatal period: Developmental patterns of plasma testosterone, 4-androstenedione, dehydroepiandrosterone and its sulfate in premature and small for date infants as compared with that of full-term infants

Abstract

The patterns of the plasma concentrations of testosterone (T), 4-androstenedionc (Δ 4), dehydroepiandrosterone (DHA) and its sulfate (DHAS) and of Cortisol (F) observed during the first year of life in 96 premature (group I), 23 small for date (group 2) were compared to those of 430 full-term infants (group 3). The per cent of T and DHA bound to plasma proteins was measured by equilibrium dialysis and the unbound levels of T and DHA determined. In group 3, testicular activity, high at birth, declined by the first week of life parallel to the clearance of hCG, and reincreased thereafter. In males, peak levels of T were observed at 15–60 days of life: from 3 to 6 months T decreased correlatively with time. The triphasic pattern of T observed during the first month of life was similar in the three groups. However, in premature infants (group 1). the post-natal testicular activation lasted significantly longer than in group 3 while, in group 2. the temporal decline in T levels was intermediate between those observed in groups 1 and 3. The pattern of T was comparable among the females of the three groups. In group 3, adrenal androgens, high at birth, decreased progressively throughout the first year of life in a like manner in both sexes. In contrast in group 1, DHA and DHAS remained at comparable high levels for the first two months of life, then declined in both sexes, but DHA and DHAS were significantly higher in females than in males until 3 months of age. In group 2 adrenal production of androgens. both in level and duration, was again intermediate of that seen in groups I and 3. Plasma F levels did not differ between groups. The plasma binding of T and DHA increased both within the first month postnatally to prepubertal values with no sex difference and similarly in the three groups. It is hypothetized that maturational processes of the interrelationships of the components of both the hypothalamo-hypophyseal-testicular axis and the hypothalamo-hypophyscal-adrenal axis are related to a similar ontogenic evolution.