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Adrenal and thyroid function in the fetus and preterm infant.

Chung HR - Korean J Pediatr (2014)

Bottom Line: The pathophysiology of systemic vasopressor-resistant hypotension is associated with low levels of circulating cortisol, a result of immaturity of hypothalamic-pituitary-adrenal axis in preterm infants under stress.In addition, although hypothyroidism is frequently observed in extremely low gestational age infants, the benefits of thyroid hormone replacement therapy remain controversial.Screening methods for congenital hypothyroidism or congenital adrenal hyperplasia in the preterm neonate are inconclusive.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Korea.

ABSTRACT
Adrenal and thyroid hormones are essential for the regulation of intrauterine homeostasis, and for the timely differentiation and maturation of fetal organs. These hormones play complex roles during fetal life, and are believed to underlie the cellular communication that coordinates maternal-fetal interactions. They serve to modulate the functional adaptation for extrauterine life during the perinatal period. The pathophysiology of systemic vasopressor-resistant hypotension is associated with low levels of circulating cortisol, a result of immaturity of hypothalamic-pituitary-adrenal axis in preterm infants under stress. Over the past few decades, studies in preterm infants have shown abnormal clinical findings that suggest adrenal or thyroid dysfunction, yet the criteria used to diagnose adrenal insufficiency in preterm infants continue to be arbitrary. In addition, although hypothyroidism is frequently observed in extremely low gestational age infants, the benefits of thyroid hormone replacement therapy remain controversial. Screening methods for congenital hypothyroidism or congenital adrenal hyperplasia in the preterm neonate are inconclusive. Thus, further understanding of fetal and perinatal adrenal and thyroid function will provide an insight into the management of adrenal and thyroid function in the preterm infant.

No MeSH data available.


Related in: MedlinePlus

Steroid biosynthesis. The fetal zone of the human fetal adrenal cortex is capable of performing the reactions in the box (dotted line). DHEA, dehydroepiandrosterone; DHEA-S, dehydroepiandrosterone sulfate; 11βHSD, 11β hydroxysteroid dehydrogenase.
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Figure 1: Steroid biosynthesis. The fetal zone of the human fetal adrenal cortex is capable of performing the reactions in the box (dotted line). DHEA, dehydroepiandrosterone; DHEA-S, dehydroepiandrosterone sulfate; 11βHSD, 11β hydroxysteroid dehydrogenase.

Mentions: The fetal adrenal gland expresses five steroidogenic enzymes: 17-hydroxylase and 17, 20-desmolase (CYP17 or P450c17), 21-hydroxylase (CYP21A2 or P450c21), cholesterol side-chain cleavage (CYP11A1 or P450scc), aldosterone synthase (CYP11B2 or P450c11), and 3β-hydroxysteroid dehydrogenase (3βHSD)12). Since the FZ has relatively high steroid sulfotransferase activity and low 3βHSD activity, the major steroid products of the fetal adrenal gland are dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEA-S)14), and there is a limited amount of cortisol and aldosterone (Fig. 1). Fetal steroidogenesis is largely programmed to produce inactive products, and provide DHEA substrates for placental estrone and estradiol production14). There is complementary activity between the enzymes involved in steroid formation and transformation between the placental and fetal compartments15) (Figs. 1, 2).


Adrenal and thyroid function in the fetus and preterm infant.

Chung HR - Korean J Pediatr (2014)

Steroid biosynthesis. The fetal zone of the human fetal adrenal cortex is capable of performing the reactions in the box (dotted line). DHEA, dehydroepiandrosterone; DHEA-S, dehydroepiandrosterone sulfate; 11βHSD, 11β hydroxysteroid dehydrogenase.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4219944&req=5

Figure 1: Steroid biosynthesis. The fetal zone of the human fetal adrenal cortex is capable of performing the reactions in the box (dotted line). DHEA, dehydroepiandrosterone; DHEA-S, dehydroepiandrosterone sulfate; 11βHSD, 11β hydroxysteroid dehydrogenase.
Mentions: The fetal adrenal gland expresses five steroidogenic enzymes: 17-hydroxylase and 17, 20-desmolase (CYP17 or P450c17), 21-hydroxylase (CYP21A2 or P450c21), cholesterol side-chain cleavage (CYP11A1 or P450scc), aldosterone synthase (CYP11B2 or P450c11), and 3β-hydroxysteroid dehydrogenase (3βHSD)12). Since the FZ has relatively high steroid sulfotransferase activity and low 3βHSD activity, the major steroid products of the fetal adrenal gland are dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEA-S)14), and there is a limited amount of cortisol and aldosterone (Fig. 1). Fetal steroidogenesis is largely programmed to produce inactive products, and provide DHEA substrates for placental estrone and estradiol production14). There is complementary activity between the enzymes involved in steroid formation and transformation between the placental and fetal compartments15) (Figs. 1, 2).

Bottom Line: The pathophysiology of systemic vasopressor-resistant hypotension is associated with low levels of circulating cortisol, a result of immaturity of hypothalamic-pituitary-adrenal axis in preterm infants under stress.In addition, although hypothyroidism is frequently observed in extremely low gestational age infants, the benefits of thyroid hormone replacement therapy remain controversial.Screening methods for congenital hypothyroidism or congenital adrenal hyperplasia in the preterm neonate are inconclusive.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Korea.

ABSTRACT
Adrenal and thyroid hormones are essential for the regulation of intrauterine homeostasis, and for the timely differentiation and maturation of fetal organs. These hormones play complex roles during fetal life, and are believed to underlie the cellular communication that coordinates maternal-fetal interactions. They serve to modulate the functional adaptation for extrauterine life during the perinatal period. The pathophysiology of systemic vasopressor-resistant hypotension is associated with low levels of circulating cortisol, a result of immaturity of hypothalamic-pituitary-adrenal axis in preterm infants under stress. Over the past few decades, studies in preterm infants have shown abnormal clinical findings that suggest adrenal or thyroid dysfunction, yet the criteria used to diagnose adrenal insufficiency in preterm infants continue to be arbitrary. In addition, although hypothyroidism is frequently observed in extremely low gestational age infants, the benefits of thyroid hormone replacement therapy remain controversial. Screening methods for congenital hypothyroidism or congenital adrenal hyperplasia in the preterm neonate are inconclusive. Thus, further understanding of fetal and perinatal adrenal and thyroid function will provide an insight into the management of adrenal and thyroid function in the preterm infant.

No MeSH data available.


Related in: MedlinePlus