Concentrations of deoxycorticosterone, deoxycorticosterone sulfate, and progesterone in maternal venous serum and umbilical arterial and venous sera

Management of adrenal tumors in pregnancy

Adrenal diseases, including Cushing syndrome (CS), primary aldosteronism (PA), pheochromocytoma, and adrenocortical carcinoma, are uncommon in pregnancy; a high degree of clinical suspicion must exist. Physiologic changes to the hypothalamus-pituitary-adrenal axis in a normal pregnancy result in increased cortisol, renin, and aldosterone levels, making the diagnosis of CS and PA in pregnancy challenging. However, catecholamines are not altered in pregnancy and allow a laboratory diagnosis of pheochromocytoma that is similar to that of the nonpregnant state. Although adrenal tumors in pregnancy result in significant maternal and fetal morbidity, and sometimes mortality, early diagnosis and appropriate treatment often improve outcomes.

Steroid profiling in pregnancy: a focus on the human fetus

In this review we focused on steroid metabolomics in human fetuses and newborns and its role in the physiology and pathophysiology of human pregnancy and subsequent stages of human life, and on the physiological relevance of steroids influencing the nervous systems with regards to their concentrations in the fetus. Steroid profiling provides valuable data for the diagnostics of diseases related to altered steroidogenesis in the fetal and maternal compartments and placenta. We outlined a potential use of steroid metabolomics for the prediction of reproductive disorders, misbalance of hypothalamic-pituitary-adrenal axis, and impaired insulin sensitivity in subsequent stages of human life. A possible role of steroids exhibiting a non-genomic effect in the development of gestational diabetes and in the neuroprotection via negative modulation of AMPA/kainate receptors was also indicated. Increasing progesterone synthesis and catabolism, declining production of tocolytic 5β-pregnane steroids, and rising activities of steroid sulfotransferases with the approaching term may be of importance in sustaining pregnancy. An increasing trend was demonstrated with advancing gestation toward the production of ketones (and 3β-hydroxyl groups in the case of 3α-hydroxy-steroids) was demonstrated in the fetus on the expense of 3α-hydroxy-, 17β-hydroxy-, and 20α-hydroxy-groups weakening in the sequence C17, C3, and C20. There was higher production of active progestogen but lower production of active estrogen and GABAergic steroids with the approaching term. Rising activities of placental CYP19A1 and oxidative isoforms of HSD17B, and of fetal CYP3A7 with advancing gestation may protect the fetus from hyperestrogenization. This article is part of a Special Issue entitled 'Pregnancy and Steroids'.

Adrenal disorders in pregnancy

Pregnancy is marked by alterations in a number of endocrine systems, including activation of the renin-angiotensin-aldosterone system and the hypothalamic-pituitary-adrenal axis. The placenta, the fetal adrenal glands and the liver constitute an interactive endocrine entity, known as the fetoplacental unit. In the fetoplacental unit, the fetal adrenal glands are the primary source of dehydroepiandrosterone sulphate, which is further metabolized by the fetal liver and placenta to produce a variety of oestrogens. Several disorders can affect both the fetal and maternal adrenal glands during pregnancy. The most common fetal adrenal disorder, steroid 21-hydroxylase deficiency, leads to abnormalities in sexual development and can be life threatening for the neonate. Although rare, maternal adrenal disorders are associated with considerable maternal mortality and morbidity if not promptly recognized and treated. However, diagnosis is often difficult to establish because of the endocrine changes occurring during normal pregnancies and the lack of reference values for the majority of the adrenal steroids. This Review provides an overview of adrenal steroid metabolism during pregnancy and focuses on diagnosis and treatment of the most common fetal and maternal adrenal disorders.

Depot-specific steroidogenic gene transcription in human adipose tissue

CONTEXT

Sex steroids (androgens and oestrogens) and corticosteroids (glucocorticoids and mineralocorticoids) have a major impact on fat distribution. Several genes involved in steroid synthesis and metabolism, such as 11beta-hydroxysteroid dehydrogenase type 1 and aromatase, are known to be expressed within adipose tissue, thus modulating local steroid levels; however, our knowledge of which genes are expressed and at what level is incomplete.

OBJECTIVE

To detect by real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) which of 13 key steroidogenic genes are transcribed within human adipose tissue and to assess whether mRNA levels differ significantly between the subcutaneous abdominal and omental adipose depots.

PATIENTS

Eight women undergoing caesarean section [age 29.1 +/- 6.5 years, body mass index (BMI) 28.9 +/- 8.4 kg/m(2)].

RESULTS

Genes transcribed in both depots were StAR (steroidogenic acute regulatory protein), CYP11A1 (side-chain cleavage enzyme), HSD3B2 (3beta-hydroxysteroid dehydrogenase type 2), CYP21B (21-hydroxylase), CYP19 (aromatase), HSD11B1 (11beta-hydroxysteroid dehydrogenase type 1), HSD17B3, HSD17B5, HSD17B7 (17beta-hydroxysteroid dehydrogenase types 3, 5 and 7) and SRD5A2 (5alpha-reductase type 2). All but SRD5A2 varied significantly in abundance between depots. CYP17 (17alpha-hydroxylase), CYP11B1 (11beta-hydroxylase) and CYP11B2 (aldosterone synthase) transcription were not detected.

CONCLUSIONS

This study confirms and significantly extends our knowledge of steroidogenic gene expression within adipose tissue, showing that transcript levels are depot specific. We have demonstrated that de novo synthesis from cholesterol of sex steroids, cortisol and aldosterone is not possible because of the absence of key steroidogenic mRNAs. Instead, the pattern of transcription suggests that 11-deoxycorticosterone, a mineralocorticoid, would be the ultimate product of any de novo adipose synthesis.

Fetal and maternal adrenals in human pregnancy

Human pregnancy is marked by alterations in several endocrine systems--perhaps most notably, the striking increase in steroid hormone production by the adrenals of the fetus and mother. Morphologically and physiologically, the human fetal adrenal glands are remarkable organs. In proportion to the adult organs, the adrenal cortex is the largest organ of the fetus. At term, they produce more steroid and weigh the same as adrenal glands of the adult. Much of the steroid that is released by the fetal and maternal adrenals during pregnancy is the sulfated form of dehydroepiandrosterone (DHEA-S), which is used by the placenta to produce estrogens. Herein, we discuss the physiologic and pathophysiologic hormonal changes of the fetal and maternal adrenals during the course of pregnancy.

Origin of deoxycorticosterone sulfate (DOC-SO4) in plasma of pregnant women: pregnenolone-3,21-disulfate is a placental precursor of DOC-SO4

The plasma levels of deoxycorticosterone sulfate (DOC-SO4) in near-term pregnant women are approximately 100 times those in plasma of men or non-pregnant women. Yet, neither the tissue site of synthesis nor the precursor of DOC-SO4 that enters maternal plasma is known. Several potential sources have been excluded: plasma DOC-SO4 is not derived from plasma DOC; and the secretion of C21-steroids (other than aldosterone) from the maternal adrenals during human pregnancy is not increased. Similarly, the transfer of DOC-SO4 from fetal plasma cannot account for the high level of DOC-SO4 in the maternal compartment, and a reduced clearance of plasma DOC-SO4 during pregnancy cannot account for the high levels of DOC-SO4. Indeed, the rate of clearance of DOC-SO4 from plasma is 10-100 times that of most other steroid sulfates. To address this question further, we evaluated the possibility that fetal plasma pregnenolone-3,21-disulfate serves as a precursor for DOC-SO4 formation in the placenta. The preferential hydrolysis of the 3beta-sulfate of pregnenolone-3,21-disulfate in placenta would give rise to pregnenolone-21-monosulfate, which, if acted upon by placental 3beta-hydroxysteroid dehydrogenase/delta5 --> 4 isomerase, could give DOC-SO4. [3H]Pregnenolone-3,21-disulfate was incubated with minces of human placental tissue for 5, 20, 60 and 120 min. Radiolabelled DOC-SO4, DOC, and pregnenolone-21-monosulfate were isolated from the incubation media and quantified. After a 5 min incubation, 7.5% of substrate was converted to DOC-SO4; and after 20, 60 and 120 min approximately 30% of the [3H]pregnenolone-3,21-disulfate was recovered from the media of these incubations as [3H]DOC-SO4. [3H]DOC was also present in the incubation media and the concentrations of this product increased as a function of incubation time. Therefore, pregnenolone-3,21-disulfate, which is present in very high concentrations in fetal plasma (approximately 1000 ng/ml), is metabolized in the placenta to DOC-SO4. Because of the fetal and maternal vascular arrangements of the hemochorioendothelial placenta of human pregnancy, steroids produced in syncytiotrophoblasts preferentially enter the intervillous space; thus, fetal plasma pregnenolone-3,21-disulfate may serve as a placental precursor of maternal plasma DOC-SO4.

Origin of deoxycorticosterone and deoxycorticosterone sulfate in human pregnancy: absence of steroid 21-sulfatase activity in sulfatase-deficient placenta

The activity of steroid 21-sulfatase, the enzyme that catalyzes the hydrolysis of deoxycorticosterone sulfate (DOC-SO4) is demonstrable in human placenta. Thus, it is possible that this placental enzyme, by way of the hydrolysis of either DOC-SO4 or 21-hydroxypregnenolone mono- or di-sulfate of fetal origin, may be important in the biosynthesis of DOC, which is present in the plasma of pregnant women in high concentration. To investigate this issue further, we evaluated steroid 21-sulfatase activity in microsomal preparations of a sulfatase-deficient placenta. Immediately after delivery, at term, of a living male fetus with sulfatase deficiency, a microsome-enriched fraction of placental tissue was prepared; sulfatase activity was evaluated by use of three substrates, viz. dehydroisoandrosterone sulfate (DS), estrone sulfate (E1-SO4), and DOC-SO4, in various concentrations. Similar incubations were conducted with aliquots of a microsome-enriched fraction prepared from placental tissue of a normal fetus that was delivered, at term, within minutes of the time of delivery of the infant with sulfatase deficiency. In microsomal fractions from the normal placenta, each of the steroid sulfates was hydrolyzed. In the absence of microsomes, and in the presence of microsomal fractions from the sulfatase-deficient placenta, the hydrolysis of DOC-SO4 and DS was not detected. Moreover, in microsomes prepared from the sulfatase-deficient placenta, E1-SO4 was hydrolyzed at a rate that was only 10% of that in incubations with microsomal preparations of the normal placenta. We conclude that with sulfatase deficiency, the placenta is deficient not only in sulfatase activity for steroid-3-sulfates but for steroid 21-sulfates, e.g. DOC-SO4, as well.

A radioimmunoassay for deoxycorticosterone sulfate without hydrolysis

The hapten of deoxycorticosterone sulfate was synthesized and linked to the carrier protein through the C-4 position on the steroid nucleus. The antisera raised against this antigen in guinea pigs exhibited high affinity (Ka = 1.86 x 10(9) M-1) and excellent specificity for deoxycorticosterone sulfate. It was found that deoxycorticosterone sulfate can be determined in the range of 50-5000 pg, and this radioimmunoassay in plasma shows a coefficient of variation (CV) less than 10%.

Umbilical cord plasma concentrations of deoxycorticosterone sulfate in anencephalic fetuses

In the present investigation, we determined the levels of deoxycorticosterone sulfate in mixed umbilical cord plasma of anencephalic abortuses and newborn infants. The anencephalic fetus is an interesting model with respect to the production of deoxycorticosterone and deoxycorticosterone sulfate on several accounts. There is profound adrenal atrophy in most such fesuses, and, in consequence, there also is relatively profound hypoestrogenism. This is an important consideration in the formation of deoxycorticosterone and deoxycorticosterone sulfate since it is known that estrogen acts to stimulate extra-adrenal steroid 21-hydroxylase and 21-hydroxysteroid sulfotransferase activities. The plasma levels of deoxycorticosterone sulfate in 22 anencephalic abortuses and newborn infants delivered between 21.5 and 45.5 weeks of gestation ranged from 1.8 to 30.3 ng/ml. The concentrations of deoxycorticosterone sulfate in umbilical cord plasma of anencephalic fetuses and newborn infants were not related to gestational age or method of delivery and, at term, were less than 13% of those in umbilical cord plasma of normal newborn infants. These data can be interpreted to indicate (1) that deoxycorticosterone sulfate normally is secreted directly by the fetal adrenal or (2) that placental estrogen normally derived largely from fetal adrenal dehydroisoandrosterone sulfate is essential for the maintenance of plasma deoxycorticosterone sulfate levels in the fetus by stimulating extra-adrenal deoxycorticosterone sulfate production from plasma progesterone, or both.

The origin of and metabolic fate of deoxycorticosterone and deoxycorticosterone sulfate in pregnant women and their fetuses

DOC and DOC-SO4, which are present in large amounts in the blood of pregnant women, are derived from sources other than maternal adrenal. Other investigators demonstrated that treatment of near-term pregnant women with ACTH or dexamethasone did not cause alterations in the blood levels of DOC. To define the source(s) of DOC and DOC-SO4 in plasma of pregnant women, we evaluated the conversion of plasma progesterone (P) to DOC in extraadrenal sites. DOC is formed from plasma P and, provided that the pregnancy is one characterized by the usual large production of estrogen, DOC production in a given woman is proportional to the level of P in plasma. Unlike other steroid conversions or interconversions, however, the fractional conversion of P to DOC among apparently normal persons varied widely 0.011 +/- 0.003 (mean +/- SEM, n = 40, range = 0.001 to 0.030). In women pregnant with a normal living fetus, the product of the production rate of P and the fractional conversion of P to DOC is sufficient to account for the majority of DOC produced in the mother. There may be a second source of DOC, i.e. the transfer of DOC from the fetal to the maternal compartment in a manner that involves (a) direct transfer of DOC by way of trophoblast and (b) by desulfurylation of DOC-SO4 from fetal umbilical arterial plasma in trophoblast and thence transfer of DOC liberated in trophoblast to the maternal compartment. Presently, it is clear that DOC-SO4 in blood of pregnant women is not derived from plasma DOC; and there is little or no evidence in support of the proposition that DOC-SO4 (as a sulfoconjugate) is transferred from the fetal to the maternal compartment because of placental hydrolysis to DOC. Among the extraadrenal tissue sites identified as those in which 21-hydroxylation of plasma P could be effected are some also believed to be tissue sites of mineralocorticosteroid action, viz, kidney, aorta, thymus, and spleen. Quantitatively, the origin of DOC in the fetus is not as clear as in the maternal compartment; yet, many tissues of the fetus have been identified in which both steroid 21-hydroxylase and 21-hydroxysteroid sulfotransferase activity are present. Thus, in the human fetus, extraadrenal as well as adrenal production of DOC and DOC-SO4 are possible.

Ontogeny of human fetal plasma progesterone, deoxycorticosterone, and deoxycorticosterone sulfate

The concentrations of progesterone, deoxycorticosterone (DOC), and deoxycorticosterone sulfate (DOC-SO4) were determined in mixed umbilical cord plasma of abortuses and newborn infants delivered between 18 and 42 weeks' gestation. A wide range of values among individual samples was found for progesterone (224 to 2,152 ng/ml), DOC (1.6 to 10.4 ng/ml), and DOC-SO4 (17 to 154 ng/ml). Levels of progesterone and DOC in mixed umbilical cord plasma were not correlated; those of DOC and DOC-SO4 were positively correlated significantly (r = 0.3945, P less than 0.001). Whereas the mean plasma levels of DOC were similar throughout gestation, significant variation, as a function of gestational age, was found for progesterone and DOC-SO4, with levels of these steroids generally being higher near term than earlier in gestation. The administration of glucocorticosteroids to the mother resulted in a significant decrease (p less than 0.001) in plasma concentrations of DOC and DOC-SO4 in the newborn infant; levels of progesterone in umbilical cord plasma were not affected by maternal glucocorticosteroid treatment. These results suggest that the fetal adrenal glands play a direct, or possibly an indirect, role in the production of the DOC and DOC-SO4 that is present in the fetal compartment. In addition, since fetal plasma levels of progesterone are quite high throughout gestation, the potential exists for circulating progesterone to serve as a precursor for adrenal and extra-adrenal production of DOC and DOC-SO4.

Metabolic clearance rate of plasma deoxycorticosterone sulfate in men and women

In the present investigation, we determined the metabolic clearance rate of plasma deoxycorticosterone sulfate in adult men and nonpregnant women and in one women pregnant at 42 weeks gestation with an anencephalic fetus. The values obtained varied from 618 to 10701/24 h. The metabolic clearance rate of deoxycorticosterone sulfate, expressed as a function of body surface area, was 495 +/- 31.71/24 h/m2 (mean +/- SEM) and was not significantly different among men and nonpregnant women. In a woman pregnant with an anencephalic fetus at 42 weeks gestation, the metabolic clearance rate of deoxycorticosterone sulfate was 6441/24 h/m2. We suggest that the high clearance rate of this steroid 21-sulfate, compared with those of other steroid sulfates, is due to rapid excretion of deoxycorticosterone sulfate into bile and irreversible metabolism in intestine by bacterial enzymes.

Steroid 21-sulfatase activity in human placenta

Intravenously administered [3H]-deoxycorticosterone sulfate is not metabolized by way of deoxycorticosterone in men or non-pregnant women. Thus, it can be implied that steroid 21-sulfatase is not active in human tissues. On the other hand, evidence has accrued that deoxycorticosterone sulfate is hydrolyzed in human placenta. In the present investigation, we sought to ascertain if steroid 21-sulfatase activity were present in placenta and, if so, to characterize the enzyme activity in this tissue. Steroid 21-sulfatase activity was found to be present in microsome-enriched fractions prepared from human placental tissue; conditions of linearity of the reaction with time and protein concentration were established and the apparent KM of the enzyme for deoxycorticosterone sulfate was 100 microM. Thus, deoxycorticosterone sulfate, which is present in high concentration in plasma of the human fetus, may enter trophoblast wherein it could be hydrolyzed; the deoxycorticosterone formed could be secreted into the maternal circulation. Such a process, together with deoxycorticosterone formation from plasma progesterone in extraadrenal sites, could account for the high concentrations of deoxycorticosterone that are present in plasma of near-term pregnant women.

Conversion of progesterone to deoxycorticosterone in the human fetus: steroid 21-hydroxylase activity in fetal tissues

Steroid 21-hydroxylase activity was assayed in microsome-enriched fractions prepared from homogenates of a number of human fetal tissues. The activity of this enzyme was demonstrable in several tissues in addition to the adrenal, kidney, and gonads. The highest specific activities of the enzyme were found in adrenal, skin, kidney and urinary bladder. In addition, 21-hydroxylation of progesterone was demonstrated in microsome-enriched preparations of pancreas, thymus, spleen, testis and ovary. Thus a number of fetal tissues may contribute to the formation of deoxycorticosterone, which is present in high concentrations in plasma of the human fetus compared with those in men and nonpregnant women. Moreover, the potential for the in situ formation of DOC in presumed tissue sites of mineralocorticosteroid action was demonstrated.