Abnormal Adrenal Steroidogenesis in Growth-Retarded Newborn Infants

Abstract

ABSTRAm. The results of prior studies suggest that abnormalities of development and function of the fetal adrenal occur in pregnancies complicated by intrauterine fetal growth retardation (IUGR). In the present investigation, we sought to extend such studies by matching IUGR infants with normally grown infants of women in whom pregnancy complications, delivery method, and gestational age were comparable. In 47 vaginally delivered, IUGR infants (38 f 2 wk, mean f SD; 2244 f 589 g body weight), the levels of dehydroepiandrosterone sulfate (DS) in umbilical cord serum (4.48 f 2.94 pmol/L) were lower ( p = 0.035) than those (5.94 f 3.63 pmol/L) of 47 normal weight infants (38 f 2 wk; 3107 f 527 g). Yet, umbilical cord serum levels of cortisol in IUGR infants (455 f 189 nmol/L) were slightly higher than those of the control infants (408 f 247 nmol/L). The DS/cortisol molar ratio in IUGR infants (10.5 2 6.8) was 41% lower ( p = 0.0013) than that of the control infants (17.7 f 13). Also, the estimated DS plasma pool in IUGR infants (521 f 349 nmol) was strikingly lower ( p = 0.0018) than that of the control infants (800 f 480 nmol); the estimated plasma pools of cortisol were equivalent (growth-retarded: 53 f 27 nmol; control: 55 f 34 nmol). Although we anticipated that total cholesterol and apo B levels in IUGR infants would be increased due to reduced adrenal utilization of LDL for DS production, such was not the case. We conclude that a selective deficiency of DS production occurs in the IUGR fetus. (Pediatr Res 35: 633-636, 1994) Abbreviations IUGR, intrauterine growth retardation or retarded DS, dehydroepiandrosterone sulfate PIH, pregnancy-induced hypertension Estrogen production in human pregnancy is largely dependent on the production of DS by the fetal adrenals and subsequent aromatization of DS and 16 hydroxy-DS (formed in the fetal liver from DS) in the placenta. In normal fetuses, plasma DS concentrations seem to remain relatively constant during the latter half of gestation with the exception of a progressive rise during the last 6-8 wk of intrauterine life (I). Thus, the fetal plasma pool of DS increases steadily between approximately 20 and 32 wk in concert with fetal growth and then increases strikingly near term (I), giving rise to the accelerated increase in estrogen production that occurs at this time (2,3). In pregnancies complicated by IUGR, maternal estrogen levels are usually sub- normal (4, 5). Impaired estrogen production in such circumstances could result from several factors, including reduced mass of the placenta wherein estrogen formation occurs and decreased adrenal production of DS by the growth-retarded fetus. We (3,6-8) and others (9) have found subnormal DS concentrations in umbilical cord blood of infants believed to be stressed in utero as a consequence of various pregnancy complications. On the other hand, many such infants have normal to increased cortisol levels (6-8). Such findings are suggestive of stress-associated alterations in the adrenal steroid biosynthetic pathway. The...

Differences in expression and activity of 11β-hydroxysteroid dehydrogenase type 1 and 2 in human placentas of term pregnancies according to birth weight and gender

“…However, in this regard, there are some discordant observations (13,14). No differences in F from mixed umbilical cord serum in SGA newborns compared with matched AGA controls have been detected (14). Of note, in this later report, ten subjects were born preterm and three postterm, and since gestational age influences adrenal function, this result might be biased.…”

“…In addition, we found higher cord F levels in SGA at term newborns. However, in this regard, there are some discordant observations (13,14). No differences in F from mixed umbilical cord serum in SGA newborns compared with matched AGA controls have been detected (14).…”

Blunted Stress Response in Small for Gestational Age Neonates

“…Growth-restricted preterm infants (Ͻ32 wk of gestation) seem to have a lower steroidogenic capacity than infants with uninhibited fetal growth in response to ACTH stimulation leading to an insufficient response to stress (42). This may be related to enzyme deficiencies in the adrenal cortex (43). However, ACTH stimulation cannot differentiate adrenal and pituitary causes of a diminished response.…”

Fetal Plasma Leptin Concentrations: Relationship with Different Intrauterine Growth Patterns from 19 Weeks to Term

“…Because it is well known that fat mass in these fetuses is poorly represented, it is difficult to explain these findings. However, there are many potential explanations, among which is the presence of elevated levels of endogenous corticosteroid hormones (26,27) leading to an increased leptin synthesis (28). Moreover, one might speculate on the role of the placenta, in that the regulation of placental leptin production is not understood yet, but could be associated with changes in relation to glucose and insulin and eventually could be linked to the transfer of glucose and amino acids, which are known to be altered in IUGR (29,30).…”