Alternative pathway androgen biosynthesis and human fetal female virilization.

Androgen biosynthesis in the human fetus proceeds through the adrenal sex steroid precursor dehydroepiandrosterone, which is converted to testosterone in the gonads, followed by further activation to 5α-dihydrotestosterone in genital skin, thereby facilitating male external genital differentiation. Congenital adrenal hyperplasia due to P450 oxidoreductase deficiency results in disrupted dehydroepiandrosterone biosynthesis, explaining undervirilization in affected boys. However, many affected girls are born virilized, despite low circulating androgens. We hypothesized that this is due to a prenatally active, alternative androgen biosynthesis pathway from 17α-hydroxyprogesterone to 5α-dihydrotestosterone, which bypasses dehydroepiandrosterone and testosterone, with increased activity in congenital adrenal hyperplasia variants associated with 17α-hydroxyprogesterone accumulation. Here we employ explant cultures of human fetal organs (adrenals, gonads, genital skin) from the major period of sexual differentiation and show that alternative pathway androgen biosynthesis is active in the fetus, as assessed by liquid chromatography-tandem mass spectrometry. We found androgen receptor expression in male and female genital skin using immunohistochemistry and demonstrated that both 5α-dihydrotestosterone and adrenal explant culture supernatant induce nuclear translocation of the androgen receptor in female genital skin primary cultures. Analyzing urinary steroid excretion by gas chromatography-mass spectrometry, we show that neonates with P450 oxidoreductase deficiency produce androgens through the alternative androgen pathway during the first weeks of life. We provide quantitative in vitro evidence that the corresponding P450 oxidoreductase mutations predominantly support alternative pathway androgen biosynthesis. These results indicate a key role of alternative pathway androgen biosynthesis in the prenatal virilization of girls affected by congenital adrenal hyperplasia due to P450 oxidoreductase deficiency.

Zone-specific reference ranges of fetal adrenal artery Doppler indices: a longitudinal study.

BACKGROUND: The fetal adrenal gland is a highly vascularized organs and develops two recognizable distinct zones in uetro, inner fetal zone (FZ) and outer definitive zone (DZ). Based on the region supplied, middle adrenal artery (MAA) mainly contribute to FZ while inferior adrenal artery (IAA) mainly to the inferior part of DZ. The purpose of this study was to establish reference ranges of adrenal artery Doppler indices of IAA and MAA, and assess zonal difference of blood supply to fetal adrenal gland. METHODS: The pulsatility index (PI), resistance index (RI), and systolic:diastolic ratio (S/D) of the IAA and MAA were obtained serially at 4-week intervals in normal fetuses. The MAA and IAA were referred based on the course and location in the gland: IAA referring the artery that mainly branches from the renal artery and walks along the renal upper pole, distributing the inferoposterior part of DZ in the adrenal gland while MAA as arterial blood flowing along the single central adrenal vein in the medial part of the gland. Multilevel modeling was performed to establish the gestational age-associated reference ranges for IAA and MAA. Differences in Doppler indices between the IAA and MAA were assessed. RESULTS: One hundred sixty-eight fetuses with 843 observations were included. The IAA had a higher detection rate than the MAA (100% vs 89.2%, p < 0.05). The resistance of IAA had a reduction around 35 weeks of gestation and that of MAA remained unchanged throughout the second half of pregnancy. Lower PI, RI and S/D were observed in the MAA than in the IAA (p < 0.05) from 752 paired measurements. CONCLUSION: There is a zonal difference in blood supply in favor of the fetal zone, which may correspond to its unique function. Reference ranges of Doppler parameters in adrenal artery maybe beneficial for further evaluation of fetal hemodynamics.

Longitudinal adrenal gland measurements and growth trajectories as risk markers for late preterm delivery.

BACKGROUND: The fetal adrenal gland receives rising awareness as a predictor of spontaneous preterm birth. We hereby provide longitudinal growth assessments of the fetal adrenal gland in a low risk population with an additional focus on trajectories in fetuses born preterm. METHODS: Fetal adrenal gland was assessed via transabdominal ultrasound at gestational weeks (gw) 24-26, 28-30, and 34-36 in a low-risk pregnancy cohort. Longitudinal trajectories of the total gland and the mark (so called fetal zone) as well as ratio of fetal zone width/ total widths (w/W) were analyzed using repeated ANOVA analyses. To compare trajectories of the ratio w/W for preterm and term fetuses respectively, as well as women with and without clinical signs of preterm labor, the propensity score method was applied. RESULTS: Fetal zone width increased over the course of pregnancy (p < 0.0001), while the ratio w/W decreased (p < 0.0001) (n = 327). Comparing the trajectories of the ratio w/W in fetuses born preterm (n = 11) with propensity-score matched term born fetuses (n = 22), a decrease between gw 24-26 and 28-30 was observed in both groups, which continued to decrease for the term born fetuses. However, in preterm born fetuses, the ratio increased above the term born values at gw 34-36. CONCLUSION: Our study provides for the first time longitudinal growth data on the fetal adrenal gland and supports the hypothesis that fetal zone enlargement is associated with preterm birth which could play an important role in risk-prediction.

Normal size of the fetal adrenal gland on prenatal magnetic resonance imaging.

BACKGROUND: The adrenal gland plays a vital role in fetal growth. Many disease states such as congenital adrenal hyperplasia, hemorrhage and tumors can lead to morphological changes in the gland. Ultrasound measurements of normal adrenal sizes in the fetus reported in the literature have shown a trend of increasing size with gestational age. There is no literature available on standard fetal adrenal sizes or detailed appearance by fetal MRI. OBJECTIVE: The purpose of this study was to provide MR data on the size and signal characteristics of the fetal adrenal gland throughout the second and third trimesters. MATERIALS AND METHODS: In this retrospective review, we selected 185 prenatal MRIs obtained from Jan. 1, 2014, to May 31, 2017, with normal abdominal findings for inclusion. The adrenal glands were identified in coronal, sagittal or axial T2-W planes and coronal T1-W plane when available. We measured the length and thickness of the medial and lateral limbs of the right and left adrenal glands and recorded signal intensity on T1-W and T2-W sequences, gender and gestational age in each case. RESULTS: The gestational age (GA) ranged 18-37 weeks. Visibility of the adrenal glands on T2-W images was high (90.3-97.2%) up to 30 weeks of GA but declined afterward (47.5-62.2% at 31-37 weeks). Visibility on T1-W images increased with GA, ranging from 21.4% visibility at 18-22 weeks and increasing to 40% at 35-37 weeks. Mean lengths of the adrenal gland limbs steadily increased from 8.2 mm at 18-22 weeks to 11.0 mm at 35-37 weeks. In the second trimester, adrenal glands were low in signal intensity on T2-W images and were surrounded by hyperintense perirenal fatty tissue. In the third trimester, the glands became less distinct, with increasing signal and obliteration of perirenal tissue. The glands were moderately hyperintense on T1-W images throughout pregnancy, with increasing visibility as pregnancy progressed. CONCLUSION: Normal sizes and signal intensities for adrenal glands are reported. Visibility of adrenal glands on T2-W images was 90.3-97.2% up to 30 weeks but declined thereafter. Visibility on T1-W images increased in the third trimester. Adrenal gland sizes increased with gestational age.

Fetal adrenal gland: Total gland volume and fetal zone to total gland ratio as markers of small for gestational age.

PURPOSE: Fetal adrenal gland changes have previously been investigated as novel markers of preterm labor and small for gestational age (SGA) fetuses. We aimed to compare the fetal adrenal gland parameters in SGA and appropriate for gestational age (AGA) fetuses. METHODS: A prospective cohort study was conducted on SGA fetuses with estimated fetal weight (EFW) ≤10th centile and AGA (EFW >10th centile) at 17 to 34 weeks gestation. Fetal adrenal total gland volume (TGV), TGV corrected for EFW (cTGV), fetal zone volume (FZV), FZV corrected for EFW (cFZV), and FZV:TGV ratio were compared and correlated with gestational age and EFW. Receiver operator curves assessed FZV:TGV ratio, cTGV, and cFZV in detecting SGA. RESULTS: Ultrasound examinations from 103 AGA and 50 SGA fetuses showed that (a) SGA fetuses had higher TGV (P = .002), FZV (P = .001), and FZV:TGV (P = .036) compared to AGA fetuses; (b) fetal adrenal TGV, FZV, cFZV, and FZV:TGV increase with advancing gestational age and EFW while cTGV does not; (c) Fetal adrenal changes in cTGV, cFZV, and FZV:TGV have ability to differentiate SGA; (d) FZV:TGV ratio 10 and 25 may be used to identify or exclude SGA in antenatally suspected SGA. CONCLUSIONS: We investigated the concept that SGA fetuses have measurable changes to the adrenal gland. We have shown that fetal TGV, TGV, and FZV:TGV ratio show differences between AGA and SGA with TGV remaining significant after accounting for GA at scan. These findings may be useful as potential biomarkers for diagnosing or excluding SGA.

Fetal adrenal gland size in gestational diabetes mellitus.

Background The aim of this study was to compare the adrenal gland size of fetuses of women with gestational diabetes mellitus (GDM) with that of healthy control fetuses. Methods This prospective cross-sectional study included measurements of the adrenal gland size of 62 GDM fetuses (GDM group) and 370 normal controls (control group) between the 19th and 41st week of gestation. A standardized transversal plane was used to measure the total width and the medulla width. The cortex width and an adrenal gland ratio (total width/medulla width) were calculated from these data. Adrenal gland size measurements were adjusted to the week of gestation and compared between the two groups in a multivariable linear regression analysis. A variance decomposition metric was used to compare the relative importance of predictors of the different adrenal gland size measurements. Results For all the investigated parameters of the adrenal gland size, increased values were found in the case of GDM (P < 0.05), while adjusting for the week of gestation. GDM seems to have a greater impact on the size of the cortex than on the size of the medulla. Conclusion The fetal adrenal gland is enlarged in pregnancy complicated by GDM. The width of the cortex seems to be particularly affected.

Sonographic evaluation of adrenal size in neonates (23 to 41 weeks of gestation).

BACKGROUND: Fetal adrenal gland size is known to have a positive correlation with both gestational age and estimated body weight. In contrast, some clinical observations suggest that maturation of the adrenal stress response occurs after 30 weeks of gestation. In this study, adrenal gland size at birth in extremely preterm to term neonates was investigated using ultrasonography to evaluate the adrenal developmental pattern and the impact of prematurity and perinatal factors. METHODS: The area of the right adrenal gland was measured in the first 3 h of life in 350 neonates and corrected for birth weight (BW) to determine the corrected adrenal area index (cAI). The neonates were subdivided into three groups: group 1 (before 30 weeks of gestation), group 2 (30 to 36 weeks), and group 3 (after 37 weeks). Differences in the cAI among the 3 groups were compared to estimate the impact of perinatal factors. RESULTS: The adrenal gland size was measurable in all neonates with gestational age ranging from 23 to 41 weeks. Right adrenal gland area was highly correlated with BW (r = 0.75, p < 0.01). cAI showed a significant negative correlation with gestational age in group 1 (r = - 0.67, p < 0.01), whereas it showed no correlation with gestational age in both groups 2 and 3. As for the impact of perinatal parameters on cAI, only gestational age in group 1 and only fetal distress in group 2 were correlated with cAI. In group 3, perinatal parameters such as fetal distress and low Apgar score were correlated with cAI. CONCLUSIONS: The present study demonstrated that the developmental pattern of fetal adrenal gland was different before and after 30 weeks of gestation, suggesting that the magnitude of adrenal stress response might mature after 30 weeks of gestation.

Equine fetal adrenal, gonadal and placental steroidogenesis.

Equine fetuses have substantial circulating pregnenolone concentrations and thus have been postulated to provide significant substrate for placental 5α-reduced pregnane production, but the fetal site of pregnenolone synthesis remains unclear. The current studies investigated steroid concentrations in blood, adrenal glands, gonads and placenta from fetuses (4, 6, 9 and 10 months of gestational age (GA)), as well as tissue steroidogenic enzyme transcript levels. Pregnenolone and dehydroepiandrosterone (DHEA) were the most abundant steroids in fetal blood, pregnenolone was consistently higher but decreased progressively with GA. Tissue steroid concentrations generally paralleled those in serum with time. Adrenal and gonadal tissue pregnenolone concentrations were similar and 100-fold higher than those in allantochorion. DHEA was far higher in gonads than adrenals and progesterone was higher in adrenals than gonads. Androstenedione decreased with GA in adrenals but not in gonads. Transcript analysis generally supported these data. CYP17A1 was higher in fetal gonads than adrenals or allantochorion, and HSD3B1 was higher in fetal adrenals and allantochorion than gonads. CYP11A1 transcript was also significantly higher in adrenals and gonads than allantochorion and CYP19 and SRD5A1 transcripts were higher in allantochorion than either fetal adrenals or gonads. Given these data, and their much greater size, the fetal gonads are the source of DHEA and likely contribute more than fetal adrenal glands to circulating fetal pregnenolone concentrations. Low CYP11A1 but high HSD3B1 and SRD5A1 transcript abundance in allantochorion, and low tissue pregnenolone, suggests that endogenous placental pregnenolone synthesis is low and likely contributes little to equine placental 5α-reduced pregnane secretion.

Sonographic Evaluation of Fetal Adrenal Gland in Gestational Diabetes: Relation to Fetal Growth and Maternal Biochemical Markers.

OBJECTIVES: To relate measurements and volume of the fetal adrenal gland in third trimester ultrasound in diabetic pregnancies (1) to birth weight; (2) to other sonographic markers of diabetic fetopathy (expected fetal weight, sectional area, and fractional volume in fetal limbs); and (3) to maternal biochemical markers of diabetes (HbA1c, leptin). METHODS: Fetal adrenal gland measurements were obtained between 32 and 34 weeks. The gland length, width, depth, and volume (by Virtual Organ Computer-Aided Analysis [VOCAL]) were measured for total gland and fetal zone. Fetal total and fat sectional area and fractional volume were obtained in arm and thigh. A maternal blood sample was obtained. Univariate and multivariate models were used to assess the associations. RESULTS: Thirty-nine diabetic pregnancies were included. Birth weight related significantly to total and fetal zone adrenal depth, and total adrenal volume in third trimester. Total adrenal length and corrected adrenal gland volume also showed a significant correlation to birth weight percentile in univariate and multivariate models. Total adrenal volume associated significantly to total and fat areas and volumes in fetal limbs. Both maternal leptin and HbA1c levels found a significant positive relation to fetal total adrenal volume and corrected adrenal gland volume. Total adrenal gland volume showed a significant association to maternal HbA1c level in multivariate model. CONCLUSIONS: An enlargement of the fetal adrenal gland may be observed in gestational diabetes, not only related to birth weight, but also to distinctive features of diabetic pregnancies, such as fat tissue fetal deposits or maternal biochemical markers.

"Lying-Down" Adrenal Sign: There Are Exceptions to the Rule Among Fetuses and Neonates.

A linear-shaped or "lying-down" adrenal gland is a sign often seen with the absence of the kidney in the renal fossa due to renal agenesis, renal ectopia, or horseshoe kidney. It is theorized that the presence of the kidney in the normal location within the renal fossa is important for the formation of the normal triangular inverted V or Y adrenal shape. There are exceptions to this rule whereby a kidney is missing from the renal fossa, yet a normal adrenal shape is present. This series looked at 18 cases of an empty renal fossa in fetal, neonatal, and pediatric patients and recorded the shape of the adrenal gland. Nine cases (50%) appropriately showed the linear or lying-down adrenal gland; 6 (33%) showed an exception to the rule, with a normally shaped adrenal gland; and 3 (17%) showed a pseudo exception in which the adrenal gland was linear but blended with the diaphragmatic crus to simulate a triangular adrenal gland. The sonographic characteristics of the crus are different from those of the adrenal gland; thus, this pseudo exception can be avoided by careful inspection. Because the absence of the kidney is often a difficult diagnosis, the lying-down adrenal gland sign can be a helpful secondary sign for confirming that a kidney is absent or ectopic in position and not within the renal bed.

Nomograms of the whole foetal adrenal gland and foetal zone at gestational age of 16-24 weeks.

The aim of this study was to create nomograms of the whole foetal adrenal gland and the foetal zone at 16-24 weeks of gestation in the Thai population, as well as to evaluate the relationships between the gestational age and the whole foetal adrenal gland and the foetal zone. Transabdominal measurement of the whole foetal adrenal gland and adrenal foetal zone were added to the routine biometric measurements at 16-24 weeks of gestation of singleton low-risk pregnancies. A total of 189 measurements were used for analysis. A linear correlation was observed between gestational age and the length, width and depth of the whole foetal adrenal gland at 16-24 weeks of gestation. A linear correlation was also found between gestational age and the length, width and depth of the foetal zone at 16-24 weeks of gestation. This study shows the linear growth of the foetal adrenal gland and foetal zone from 16-24 weeks of gestation. These reference values may be helpful in detecting abnormal growth of foetal adrenal gland or any abnormalities of the foetal adrenal gland. Impact Statement What is already known on this subject: Foetal adrenal glands play a pivotal role, mainly through steroidogenesis, in the regulation of the intrauterine homeostasis, and in foetal development and maturation. There is evidence to support that the foetus may be in control of the timing of its own birth by activating its hypothalamic-pituitary-adrenal axis to increase the production of dehydroepiandrosterone-sulphate to predominately induce the enlargement of the central foetal zone. What the results of this study add: This study shows the nomograms of the foetal adrenal gland and foetal zone from 16-24 weeks of gestation and the linear growth of the foetal adrenal gland and foetal zone from 16-24 weeks of gestation. What are the implications of these findings for clinical practice and/or further research:These reference values may be helpful in detecting abnormal growth of foetal adrenal gland or any abnormalities of the foetal adrenal gland.

A Brief Account of the Discovery of the Fetal/Placental Unit for Estrogen Production in Equine and Human Pregnancies: Relation to Human Medicine.

The role of steroids in human medicine is well recognized, but the major contributions made by the large domestic animals as a source of material in the discovery, isolation, and determination of the structure of the steroid hormones is less well appreciated. After a brief reminder of the early efforts to obtain a reliable source of steroids for clinical use, the narrative here is to outline one example where success was ultimately achieved for estrogen replacement therapy. Whereas knowledge of the high concentrations of estrogens in urine of pregnant women and mares dates from the late 1920s, it was not until the 1940s that the latter was shown to be a practical source. Initially, the placenta was held to be responsible, but the involvement of the fetus in each case was eventually established. The remarkable enlargement of the human fetal adrenal glands and the fetal gonads in the horse, with characteristic features of steroid secreting tissues, suggested their participation. Ultimately, it was 16-hydroxylation by the fetal liver that resulted in estriol being the major estrogen type, by far, in late human pregnancy. In the mare, the pattern of estrogen production reflected that of the growth and later regression of the fetal gonads. The characteristic production ring-B, unsaturated estrogens in the mare is derived from an alternative pathway involving retention of the additional double bond in the biosynthesis of equilin.

Molecular mechanisms of synthesis of noradrenaline as an inducer of development in the adrenal glands of rats in ontogenesis.

The level of gene expression and the protein content of tyrosine hydroxylase and dopamine ß-hydroxylase were determined. In the perinatal period of rats, when noradrenaline functions as a morphogenetic factor, the level of gene expression of these enzymes increased and the content of protein products of these genes was almost unchanged, indicating the difference in the regulatory mechanisms of their transcription and translation.

Association of microRNA 21 With Biological Features and Prognosis of Neuroblastoma.

BACKGROUND: The aim of this study was to assess the differences in microRNA 21 expression among neuroblastoma (NB), embryonic tissue, and normal adrenal tissue and to identify correlations between microRNA 21 expression, the biological features of the tumor, and prognosis. METHODS: A total of 70 patients with NB were selected from December 2005 and December 2007. Real-time polymerase chain reaction was used to assess microRNA 21 expression. All patients were followed-up for 5 years. RESULTS: Significant differences in microRNA 21 expression were found between the 3 groups, with the highest expression in the NB samples (P < .001). The expression of microRNA 21 was highest in the high-risk group compared with the moderate- and low-risk groups (P < .001). The microRNA 21 expression in the MYCN amplification group was higher than in the group without amplification (P = .001). The 5-year overall survival rate of patients with NB was 71.4%. CONCLUSIONS: The higher expression of microRNA 21 in NB samples compared with embryonic and normal tissue samples predicted a close correlation between microRNA 21 expression and the biological features of NB. In patients with NB, higher microRNA 21 expression correlated with lower rates of overall survival. Therefore, microRNA 21 expression may represent a novel risk factor for determining the prognosis of patients with NB.

Nicotine Suppressed Fetal Adrenal StAR Expression via YY1 Mediated-Histone Deacetylation Modification Mechanism.

Steroidogenic acute regulatory (StAR) protein plays a pivotal role in steroidogenesis. Previously, we have demonstrated that prenatal nicotine exposure suppressed fetal adrenal steroidogenesis via steroidogenic factor 1 deacetylation. This study further explored the potential role of the transcriptional repressor Yin Yang 1 (YY1) in nicotine-mediated StAR inhibition. Nicotine was subcutaneously administered (1.0 mg/kg) to pregnant rats twice per day and NCI-H295A cells were treated with nicotine. StAR and YY1 expression were analyzed by real-time PCR, immunohistochemistry, and Western blotting. Histone modifications and the interactions between the YY1 and StAR promoter were assessed using chromatin immunoprecipitation (ChIP). Prenatal nicotine exposure increased YY1 expression and suppressed StAR expression. ChIP assay showed that there was a decreasing trend for histone acetylation at the StAR promoter in fetal adrenal glands, whereas H3 acetyl-K14 at the YY1 promoter presented an increasing trend following nicotine exposure. Furthermore, in nicotine-treated NCI-H295A cells, nicotine enhanced YY1 expression and inhibited StAR expression. ChIP assay showed that histone acetylation decreased at the StAR promoter in NCI-H295A cells and that the interaction between the YY1 and StAR promoter increased. These data indicated that YY1-medicated histone deacetylation modification in StAR promoters might play an important role in the inhibitory effect of nicotine on StAR expression.

Signal molecules during the organism development: Central and peripheral sources of noradrenaline in rat ontogenesis.

Using the method of high performance liquid chromatography with electrochemical detection, the age dynamics of the content of noradrenaline (NA) in the brain, adrenal gland, and the organ of Zuckerkandl in prenatal (18th and 21st days of embryogenesis) and early postnatal (3, 7, 15, and 30th days) periods of development was studied. The potential contribution of these organs to the formation of physiologically active concentration of noradrenalin in the blood was also assessed. The results suggest that, during the development of the organism, the activity of the sources of noradrenaline in the general circulation changes, which gives a reason to assume the existence of humoral interaction between NA-producing organs in the perinatal period of ontogenesis.

[Reciprocal Humoral Regulation of Endocrine Noradrenaline Sources in Perinatal Development of Rats].

The goal of the present study was to verify our hypothesis of humoral interaction between the norepinephrine secreting organs in the perinatal period of ontogenesis that is aimed at the sustaining of physiologically active concentration of norepinephrine in blood. The objects of the study were the transitory organs, such as brain, organ of Zuckerkandl, and adrenals, the permanent endocrine organ of rats that releases norepinephrine into the bloodstream. To reach this goal, we assessed the adrenal secretory activity (norepinephrine level) and activity of the Zuckerkandl's organ under the conditions of destructed noradrenergic neurons of brain caused by (1) their selective death induced by introduction of a hybrid molecular complex, which consisted of antibodies against dopamine-ß-hydroxylase (DBH) conjugated with saporin cytotoxin (anti-DBH-saporin) into the lateral brain ventricles of neonatal rats; and (2) microsurgical in utero destruction of embryo's brain (in utero encephalectomy). It was observed that 72 h after either pharmacological or microsurgical norepinephrine synthesis deprivation in the newborn rat's brain, the level of norepinephrine was increased in adrenals and, conversely, decreased in the Zuckerkandl's organ. Therefore, the experiments with models of chronical inhibition of norepinephrine synthesis in prenatal and early postnatal rat's brain revealed changes in the secretory activity of peripheral norepinephrine sources. This, apparently, favors the sustaining of physiologically active norepinephrine level in the bloodstream.

In vivo evidence for the crucial role of SF1 in steroid-producing cells of the testis, ovary and adrenal gland.

Adrenal and gonadal steroids are essential for life and reproduction. The orphan nuclear receptor SF1 (NR5A1) has been shown to regulate the expression of enzymes involved in steroid production in vitro. However, the in vivo role of this transcription factor in steroidogenesis has not been elucidated. In this study, we have generated steroidogenic-specific Cre-expressing mice to lineage mark and delete Sf1 in differentiated steroid-producing cells of the testis, the ovary and the adrenal gland. Our data show that SF1 is a regulator of the expression of steroidogenic genes in all three organs. In addition, Sf1 deletion leads to a radical change in cell morphology and loss of identity. Surprisingly, sexual development and reproduction in mutant animals were not compromised owing, in part, to the presence of a small proportion of SF1-positive cells. In contrast to the testis and ovary, the mutant adult adrenal gland showed a lack of Sf1-deleted cells and our studies suggest that steroidogenic adrenal cells during foetal stages require Sf1 to give rise to the adult adrenal population. This study is the first to show the in vivo requirements of SF1 in steroidogenesis and provides novel data on the cellular consequences of the loss of this protein specifically within steroid-producing cells.

Differential expression of estrogen receptor alpha in the embryonic adrenal-kidney-gonadal complex of the oviparous lizard, Calotes versicolor (Daud.).

Estrogen signalling is critical for ovarian differentiation in reptiles with temperature-dependent sex determination (TSD). To elucidate the involvement of estrogen in this process, adrenal-kidney-gonadal (AKG) expression of estrogen receptor (ERα) was studied at female-producing temperature (FPT) in the developing embryos of the lizard, Calotes versicolor which exhibits a distinct pattern of TSD. The eggs of this lizard were incubated at 31.5±0.5°C (100% FPT). The torso of embryos containing adrenal-kidney-gonadal complex (AKG) was collected during different stages of development and subjected to Western blotting and immunohistochemistry analysis. The ERα antibody recognized two protein bands with apparent molecular weight ∼55 and ∼45kDa in the total protein extracts of embryonic AKG complex of C. versicolor. The observed results suggest the occurrence of isoforms of ERα. The differential expression of two different protein isoforms may reveal their distinct role in cell proliferation during gonadal differentiation. This is the first report to reveal two isoforms of the ERα in a reptile during development. Immunohistochemical studies reveal a weak, but specific, cytoplasmic ERα immunostaining exclusively in the AKG during late thermo-sensitive period suggesting the responsiveness of AKG to estrogens before gonadal differentiation at FPT. Further, cytoplasmic as well as nuclear expression of ERα in the medulla and in oogonia of the cortex (faint activity) at gonadal differentiation stage suggests that the onset of gonadal estrogen activity coincides with sexual differentiation of gonad. Intensity and pattern of the immunoreactions of ERα in the medullary region at FPT suggest endogenous production of estrogen which may act in a paracrine fashion to induce neighboring cells into ovarian differentiation pathway.

Embryological and molecular development of the adrenal glands.

In this mini review, the embryological and functional development of the adrenal glands is presented from a molecular perspective. While acknowledging that this is a highly complex series of events, the processes are described in simple and broad strokes in a single text for the reader who is interested in this field but is not an active researcher. The origin of the adrenal glands is in the mesodermal ridge as early as the fourth week of gestation. Between the eighth and ninth weeks of gestation, the adrenal glands are encapsulated and this results in the presence of a distinct organ. There have been great strides in deciphering the very complicated molecular aspects of adrenal gland development in which multiple transcription factors have been identified, directing the adrenogonadal primordium into the adrenal cortex, kidney, or bipotential gonad. Adrenocorticotrophic hormone is critical for early development of the hypothalamic-pituitary adrenal axis. Several mutations in transcription factors, responsible for normal adrenal gland development have been found to induce the familial syndrome of congenital adrenal hypoplasia or neoplasia.