Adrenal Glucocorticoid Hormones Research Articles

PDT-Induced Activation Enhanced by Hormone Response to Treatment.

Photodynamic therapy (PDT) is a medical treatment with the use of a photosensitizing agent (PS), which, when activated by light, results in selective tissue damage with a cytotoxic effect on tumor cells. PDT leads to the induction of an acute-phase response, which results in the involvement of adrenal glucocorticoid (GC) hormones. PDT, by activating the hormonal response, affects the treatment of cancer. GC release is observed due to adrenal activity, which is driven by changes in the hypothalamic pituitary-adrenal axis triggered by stress signals emanating from the PDT treated tumor. The hormones released in this process in the context of the PDT-induced acute-phase response perform many important functions during anticancer therapy. They lead, among other things, to the systemic mobilization of neutrophils and the production of acute-phase reagents, and also control the production of immunoregulatory proteins and proteins that modulate inflammation. GCs can radically affect the activity of various inflammatory and immune cells, including the apoptosis of cancer cells. A better understanding of the modulation of GC activity could improve the outcomes of cancer patients treated with PDT.

Pediatric adrenal insufficiency: thirty years experience at a Portuguese hospital.

Adrenal insufficiency (AI) is a life-threatening condition caused by an impaired secretion of the adrenal glucocorticoid and mineralocorticoid hormones. It comprises a heterogeneous group of primary, secondary and acquired disorders. Presentation differs according to the child's age, but it usually presents with nonspecific and insidious symptoms and signs. The main purpose of this study was to describe and compare patients with primary or secondary AI. Retrospective analysis of all patients with adrenal insufficiency followed at the Pediatric Endocrinology Unit in a tertiary care Portuguese hospital over the last 30 years. Data on family history, age at the first manifestation and at etiological diagnosis, and clinical presentation (symptoms, signs and laboratory evaluation) was gathered for all patients. Twenty-eight patients with AI were included; 67.9% were male, with a median (25th-75th percentile, P25-P75) age of 1 (0.5-36) month at the first presentation. The principal diagnostic categories were panhypopituitarism (42.9%) and congenital adrenal hyperplasia (25%). The most frequent manifestations (75%) were vomiting and weight loss. They were followed for a median (P25-P75) period of 3.5 (0.6-15.5) years. In respect to neurodevelopmental delay and learning difficulties, they were more common in the secondary AI group. Despite medical advances, the diagnosis and management of AI remains a challenge, particularly in the pediatric population, and clinicians must have a high index of suspicion. An early identification of AI can prevent a potential lethal outcome, which may result from severe cardiovascular and hemodynamic instability.

Glucocorticoid circadian rhythms in immune function.

Adrenal glucocorticoid (GC) hormones are important regulators of energy metabolism, brain functions, and the immune system. Their release follows robust diurnal rhythms and GCs themselves serve as entrainment signals for circadian clocks in various tissues. In the clinics, synthetic GC analogues are widely used as immunosuppressive drugs. GC inhibitory effects on the immune system are well documented and include suppression of cytokines and increased immune cell death. However, the circadian dynamics of GC action are often neglected. Synthetic GC medications fail to mimic complex GC natural rhythms. Several recent publications have shown that endogenous GCs and their daily concentration rhythms prepare the immune system to face anticipated environmental threats. That includes migration patterns that direct specific cell population to organs and tissues best exemplified by the rhythmic expression of chemoattractants and their receptors. On the other hand, chronotherapeutic approaches may benefit the treatment of immunological diseases such as asthma. In this review, we summarise our current knowledge on the circadian regulation of GCs, their role in innate and adaptive immune functions and the implications for the clinics.

Abstract #1003618: Association of Obesity with Outcomes of Patients with Adrenal Insufficiency: A Nationwide Retrospective Analysis

Adrenal insufficiency (AI) is an uncommon but life-threatening condition that occurs secondary to impaired secretion of adrenal glucocorticoid and mineralocorticoid hormones. This condition can be caused by primary destruction or dysfunction of the adrenal glands or impairment of the hypothalamic-pituitary-adrenal axis. With the rising prevalence of obesity in the US, it is necessary to study obesity in relation to various medical conditions. This is important as obesity has a significant impact on outcomes of numerous cardiopulmonary conditions.

Patterns of cortisol and corticosterone concentrations in humpback whale (Megaptera novaeangliae) baleen are associated with different causes of death.

Baleen whales are subject to a myriad of natural and anthropogenic stressors, but understanding how these stressors affect physiology is difficult. Measurement of adrenal glucocorticoid (GC) hormones involved in the vertebrate stress response (cortisol and corticosterone) in baleen could help fill this data gap. Baleen analysis is a powerful tool, allowing for a retrospective re-creation of multiple years of GC hormone concentrations at approximately a monthly resolution. We hypothesized that whales that died from acute causes (e.g. ship strike) would have lower levels of baleen GCs than whales that died from extended illness or injury (e.g. long-term entanglement in fishing gear). To test this hypothesis, we extracted hormones from baleen plates of four humpback whales (Megaptera novaeangliae) with well-documented deaths including multiple and chronic entanglements (n = 1, female), ship strike (n = 2, male and female) and chronic illness with nutritional stress (n = 1, male). Over ~3 years of baleen growth and during multiple entanglements, the entangled whale had average corticosterone levels of 80–187% higher than the other three whales but cortisol levels were similar to two of the other three whales. The nutritionally stressed and chronically ill whale showed a slow increase in both cortisol and corticosterone spanning ~3 years, followed by a sharp decline in both hormones before death, possibly indicative of adrenal failure in this moribund individual. This whale’s correlation between cortisol and corticosterone was significant but there were no correlations in the other three whales. Our results show that cortisol and corticosterone concentrations vary according to the type and duration of illness or injury. Single-point GC concentrations should be interpreted with caution as low values can occur in whales experiencing pronounced stress and individual baselines can be highly variable. Baleen analysis is a promising tissue type for retrospective analyses of physiological responses to various stressors affecting baleen whales.

Dynamics of ACTH and Cortisol Secretion and Implications for Disease.

The past decade has seen several critical advances in our understanding of hypothalamic–pituitary–adrenal (HPA) axis regulation. Homeostatic physiological circuits need to integrate multiple internal and external stimuli and provide a dynamic output appropriate for the response parameters of their target tissues. The HPA axis is an example of such a homeostatic system. Recent studies have shown that circadian rhythmicity of the major output of this system—the adrenal glucocorticoid hormones corticosterone in rodent and predominately cortisol in man—comprises varying amplitude pulses that exist due to a subhypothalamic pulse generator. Oscillating endogenous glucocorticoid signals interact with regulatory systems within individual parts of the axis including the adrenal gland itself, where a regulatory network can further modify the pulsatile release of hormone. The HPA axis output is in the form of a dynamic oscillating glucocorticoid signal that needs to be decoded at the cellular level. If the pulsatile signal is abolished by the administration of a long-acting synthetic glucocorticoid, the resulting disruption in physiological regulation has the potential to negatively impact many glucocorticoid-dependent bodily systems. Even subtle alterations to the dynamics of the system, during chronic stress or certain disease states, can potentially result in changes in functional output of multiple cells and tissues throughout the body, altering metabolic processes, behavior, affective state, and cognitive function in susceptible individuals. The recent development of a novel chronotherapy, which can deliver both circadian and ultradian patterns, provides great promise for patients on glucocorticoid treatment.

Extensive Regulation of Diurnal Transcription and Metabolism by Glucocorticoids.

Altered daily patterns of hormone action are suspected to contribute to metabolic disease. It is poorly understood how the adrenal glucocorticoid hormones contribute to the coordination of daily global patterns of transcription and metabolism. Here, we examined diurnal metabolite and transcriptome patterns in a zebrafish glucocorticoid deficiency model by RNA-Seq, NMR spectroscopy and liquid chromatography-based methods. We observed dysregulation of metabolic pathways including glutaminolysis, the citrate and urea cycles and glyoxylate detoxification. Constant, non-rhythmic glucocorticoid treatment rescued many of these changes, with some notable exceptions among the amino acid related pathways. Surprisingly, the non-rhythmic glucocorticoid treatment rescued almost half of the entire dysregulated diurnal transcriptome patterns. A combination of E-box and glucocorticoid response elements is enriched in the rescued genes. This simple enhancer element combination is sufficient to drive rhythmic circadian reporter gene expression under non-rhythmic glucocorticoid exposure, revealing a permissive function for the hormones in glucocorticoid-dependent circadian transcription. Our work highlights metabolic pathways potentially contributing to morbidity in patients with glucocorticoid deficiency, even under glucocorticoid replacement therapy. Moreover, we provide mechanistic insight into the interaction between the circadian clock and glucocorticoids in the transcriptional regulation of metabolism.

Strategic adjustment of parental care in tree swallows: life-history trade-offs and the role of glucocorticoids.

Life-history theory predicts that optimal strategies of parental investment will depend on ecological and social factors, such as current brood value and offspring need. Parental care strategies are also likely to be mediated in part by the hypothalamic–pituitary–adrenal axis and glucocorticoid hormones. Here, we present an experiment in tree swallows (Tachycineta bicolor), a biparental songbird with wide geographical distribution, asking whether parental care is strategically adjusted in response to signals of offspring need and brood value and if so, whether glucocorticoids are involved in these adjustments. Using an automated playback system, we carried out playbacks of nestling begging calls specifically to females in two populations differing in their brood value: a northern population in Ontario, Canada (relatively higher brood value) and a southern population in North Carolina, USA (relatively lower brood value). We quantified female offspring provisioning rates before and during playbacks and plasma corticosterone levels (cort) once during late incubation and once immediately after playbacks. Females in both populations increased feeding rates temporarily during the first 2 h of playback but the increase was not sustained for the entire duration of playback (6 h). Cort levels from samples at the end of the playback did not differ between control females and females that received playbacks. However, females that had higher increases in cort between the incubation and nestling period had greater fledging success. These results suggest that females are able to strategically respond to offspring need, although the role of glucocorticoids in this strategic adjustment remains unclear.

A Mixed Glucocorticoid/Mineralocorticoid Selective Modulator With Dominant Antagonism in the Male Rat Brain.

Adrenal glucocorticoid hormones are potent modulators of brain function in the context of acute and chronic stress. Both mineralocorticoid (MRs) and glucocorticoid receptors (GRs) can mediate these effects. We studied the brain effects of a novel ligand, C118335, with high affinity for GRs and modest affinity for MRs. In vitro profiling of receptor-coregulator interactions suggested that the compound is a "selective modulator" type compound for GRs that can have both agonistic and antagonistic effects. Its molecular profile for MRs was highly similar to those of the full antagonists spironolactone and eplerenone. C118335 showed predominantly antagonistic effects on hippocampal mRNA regulation of known glucocorticoid target genes. Likewise, systemic administration of C118335 blocked the GR-mediated posttraining corticosterone-induced enhancement of memory consolidation in an inhibitory avoidance task. Posttraining administration of C118335, however, gave a strong and dose-dependent impairment of memory consolidation that, surprisingly, reflected involvement of MRs and not GRs. Finally, C118335 treatment acutely suppressed the hypothalamus-pituitary-adrenal axis as measured by plasma corticosterone levels. Mixed GR/MR ligands, such as C118335, can be used to unravel the mechanisms of glucocorticoid signaling. The compound is also a prototype of mixed GR/MR ligands that might alleviate the harmful effects of chronic overexposure to endogenous glucocorticoids.

Adrenal insufficiency.

Adrenal insufficiency is a life-threatening condition that occurs secondary to impaired secretion of adrenal glucocorticoid and mineralocorticoid hormones. This condition can be caused by primary destruction or dysfunction of the adrenal glands or impairment of the hypothalamic-pituitary-adrenal axis. In children, the most common causes of primary adrenal insufficiency are impaired adrenal steroidogenesis (congenital adrenal hyperplasia) and adrenal destruction or dysfunction (autoimmune polyendocrine syndrome and adrenoleukodystrophy), whereas exogenous corticosteroid therapy withdrawal or poor adherence to scheduled corticosteroid dosing with long-standing treatment constitute the most common cause of acquired adrenal insufficiency. Although there are classic clinical signs (eg, fatigue, orthostatic hypotension, hyperpigmentation, hyponatremia, hyperkalemia, and hypoglycemia) of adrenal insufficiency, its early clinical presentation is most commonly vague and undefined, requiring a high index of suspicion. The relevance of early identification of adrenal insufficiency is to avoid the potential lethal outcome secondary to severe cardiovascular and hemodynamic insufficiency. The clinician must be aware of the need for increased corticosteroid dose supplementation during stress periods.

Glucocorticoids Increase Excitotoxic Injury and Inflammation in the Hippocampus of Adult Male Rats

Background/Aims: Stress exacerbates neuron loss in many CNS injuries via the actions of adrenal glucocorticoid (GC) hormones. For some injuries, this GC endangerment of neurons is accompanied by greater immune cell activation in the CNS, a surprising outcome given the potent immunosuppressive properties of GCs. Methods: To determine whether the effects of GCs on inflammation contribute to neuron death or result from it, we tested whether nonsteroidal anti-inflammatory drugs could protect neurons from GCs during kainic acid excitotoxicity in adrenalectomized male rats. We next measured GC effects on (1) chemokine production (CCL2 and CINC-1), (2) signals that suppress immune activation (CX3CL1, CD22, CD200, and TGF-ß), and (3) NF-κB activity. Results: Concurrent treatment with minocycline, but not indomethacin, prevented GC endangerment. GCs did not substantially affect CCL2, CINC-1, or baseline NF-κB activity, but they did suppress CX3CL1, CX3CR1, and CD22 expression in the hippocampus - factors that normally restrain inflammatory responses. Conclusions: These findings demonstrate that cellular inflammation is not necessarily suppressed by GCs in the injured hippocampus; instead, GCs may worsen hippocampal neuron death, at least in part by increasing the neurotoxicity of CNS inflammation.

Gonadal steroid hormones and the hypothalamo-pituitary-adrenal axis.

The hypothalamo-pituitary-adrenal (HPA) axis represents a complex neuroendocrine feedback loop controlling the secretion of adrenal glucocorticoid hormones. Central to its function is the paraventricular nucleus of the hypothalamus (PVN) where neurons expressing corticotropin releasing factor reside. These HPA motor neurons are a primary site of integration leading to graded endocrine responses to physical and psychological stressors. An important regulatory factor that must be considered, prior to generating an appropriate response is the animal's reproductive status. Thus, PVN neurons express androgen and estrogen receptors and receive input from sites that also express these receptors. Consequently, changes in reproduction and gonadal steroid levels modulate the stress response and this underlies sex differences in HPA axis function. This review examines the make up of the HPA axis and hypothalamo-pituitary-gonadal (HPG) axis and the interactions between the two that should be considered when exploring normal and pathological responses to environmental stressors.

The Origin of Glucocorticoid Hormone Oscillations

Author SummaryGlucocorticoid steroid hormones, such as cortisol and corticosterone, provide a rapid response to both physical and psychological stress, and act on areas of the brain that influence learning, memory, and behaviour. Glucocorticoids are released from the adrenal glands in near-hourly pulses, which results in oscillating glucocorticoid levels in the blood and in target organs. These hormone oscillations can become disrupted during ageing and in stress-related disease (e.g., major depression), so it is important to identify the underlying mechanisms that govern their dynamics. Although the origin of the oscillations is not known, it is assumed that they are generated by a neuronal “pulse generator” within the brain. In this study, we present data that challenge this hypothesis. We characterize a peripheral hormonal system and show that constant levels of corticotrophin-releasing hormone can induce and regulate hormone oscillations independent of the brain. We also describe mechanisms that can disrupt these oscillations. These findings have important implications for our understanding of glucocorticoid signalling in both health and disease, and will be important for the design of novel treatment strategies that take into account timing of hormone administration to patients undergoing steroid therapy for inflammatory or malignant disease.

Role of Adrenal Glucocorticoid Signaling in Prefrontal Cortex Gene Expression and Acute Behavioral Responses to Ethanol

Glucocorticoid hormones modulate acute and chronic behavioral and molecular responses to drugs of abuse including psychostimulants and opioids. There is growing evidence that glucocorticoids might also modulate behavioral responses to ethanol ( EtOH ). Acute EtOH activates the hypothalamic-pituitary-adrenal axis, causing the release of adrenal glucocorticoid hormones. Our prior genomic studies suggest that glucocorticoids play a role in regulating gene expression in the prefrontal cortex (PFC) of DBA2/J (D2) mice following acute EtOH administration. However, few studies have analyzed the role of glucocorticoid signaling in behavioral responses to acute EtOH . Such work could be significant, given the predictive value for the level of response to acute EtOH in the risk for alcoholism. We studied whether the glucocorticoid receptor (GR) antagonist, RU-486, or adrenalectomy (ADX) altered male D2 mouse behavioral responses to acute (locomotor activation, anxiolysis, or loss-of-righting reflex [LORR]) or repeated (sensitization) EtOH treatment. Whole-genome microarray analysis and bioinformatics approaches were used to identify PFC candidate genes possibly responsible for altered behavioral responses to EtOH following ADX. ADX and RU-486 both impaired acute EtOH (2 g/kg)-induced locomotor activation in D2 mice without affecting basal locomotor activity. However, neither ADX nor RU-486 altered the initiation of EtOH sensitization (locomotor activation or jump counts), EtOH -induced anxiolysis, or LORR. ADX mice showed microarray gene expression changes in PFC that significantly overlapped with acute EtOH -responsive gene sets derived by our prior microarray studies. Q-rtPCR analysis verified that ADX decreased PFC expression of Fkbp5 while significantly increasing Gpr6 expression. In addition, high-dose RU-486 pretreatment blunted EtOH -induced Fkbp5 expression. Our studies suggest that EtOH 's activation of adrenal glucocorticoid release and subsequent GR activation may partially modulate EtOH 's acute locomotor activation in male D2 mice. Furthermore, because adrenal glucocorticoid basal tone regulated PFC gene expression, including a significant set of acute EtOH -responsive genes, this suggests that glucocorticoid-regulated PFC gene expression may be an important factor modulating acute behavioral responses to EtOH .

Corticosteroid receptor signalling modes and stress adaptation in the brain.

Adrenal glucocorticoid hormones modulate neuronal activity to support an adaptive response to stress. They modulate brain circuitry mediating physiological responses, emotion and cognitive processing. Chronically elevated glucocorticoid exposure is however linked to the development of mental disease. Glucocorticoid effects depend on mineralo- and glucocorticoid receptors, which are powerful transcription factors, but also can act via a diversity of non-genomic mechanisms. Here, I review generic factors that determine neuronal glucocorticoid sensitivity, in relation to brain function. First, pre-receptor mechanisms determine ligand availability. Second, there may be considerable variation in the receptor splice- and translation variants. Third, other transcription factors and many transcriptional coregulators interact with steroid receptors, determining nature and magnitude of steroid responses, in part through epigenetic regulation of DNA accessibility. Which factors underlie adaptive and pathogenic effects of stress hormones is largely unknown. Genome-wide identification of the receptor-DNA interactions in specific behavioural and physiological contexts provides a way of assessing the complete genomic range of glucocorticoid modes of action. Novel ligands that induce selective activation of particular receptor signalling modes will aid our understanding of receptor signalling and may allow selective targeting of glucocorticoid effects in emotional or cognitive domains, in research and, hopefully, in clinical settings.

Stress-related hormones and genetic diversity in sea otters (Enhydra lutris)

Sea otters (Enhydra lutris) once ranged throughout the coastal regions of the north Pacific, but were extirpated throughout their range during the fur trade of the 18th and 19th centuries, leaving only small, widely scattered, remnant populations. All extant sea otter populations are believed to have experienced a population bottleneck and thus have lost genetic variation. Populations that undergo severe population reduction and associated inbreeding may suffer from a general reduction in fitness termed inbreeding depression. Inbreeding depression may result in decreased testosterone levels in males, and reduced ability to respond to stressful stimuli associated with an increase in the stress-related adrenal glucocorticoid hormones, cortisol and corticosterone. We investigated correlations of testosterone, cortisol, and corticosterone with genetic diversity in sea otters from five populations. We found a significant negative correlation between genetic diversity and both mean population-level (r2= 0.27, P < 0.001) and individual-level (r2= 0.54, P < 0.001) corticosterone values, as well as a negative correlation between genetic diversity and cortisol at the individual level (r2= 0.17, P= 0.04). No relationship was found between genetic diversity and testosterone (P= 0.57). The strength of the correlations, especially with corticosterone, suggests potential negative consequences for overall population health, particularly for populations with the lowest genetic diversity.

P.1.g.010 Oxidative stress damage of hippocampus induced memory impairment in rats

Sustained stress can have numerous pathophysiological effects. Adrenal glucocorticoid hormones are principal effectors in the stress response. They have profound effects on mood and behavior and affect neurochemical transmission and neuroendocrine control. We have used the experimental paradigm of chronic psychosocial stress in tree shrews to investigate the impact of aversive social encounters on brain structures. Chronic stress in male tree shrews which is accompanied by constantly elevated levels of glucocorticoids leads to structural changes in hippocampal neurons. Whereas dendritic atrophy of hippocampal pyramidal neurons and impairment of neurogenesis in the dentate gyrus could be demonstrated in chronically stressed tree shrews, a loss of hippocampal neurons was not observed in this animal model. The present review summarizes recent results on the question which structural changes occur during chronic stress in neurons of the brain and whether glucocorticoids might be responsible for such stress effects. The role of transmitter systems in stress-related neuronal plasticity is also discussed.

Stress, glucocorticoids and structural plasticity of the hippocampus

Sustained stress can have numerous pathophysiological effects. Adrenal glucocorticoid hormones are principal effectors in the stress response. They have profound effects on mood and behavior and affect neurochemical transmission and neuroendocrine control. We have used the experimental paradigm of chronic psychosocial stress in tree shrews to investigate the impact of aversive social encounters on brain structures. Chronic stress in male tree shrews which is accompanied by constantly elevated levels of glucocorticoids leads to structural changes in hippocampal neurons. Whereas dendritic atrophy of hippocampal pyramidal neurons and impairment of neurogenesis in the dentate gyrus could be demonstrated in chronically stressed tree shrews, a loss of hippocampal neurons was not observed in this animal model. The present review summarizes recent results on the question which structural changes occur during chronic stress in neurons of the brain and whether glucocorticoids might be responsible for such stress effects. The role of transmitter systems in stress-related neuronal plasticity is also discussed.

Dissociation of early glucocorticoid inhibition of ACTH secretion and glucose uptake in mouse AtT20 D16:16 corticotrophs.

Adrenal glucocorticoid hormones rapidly exert powerful effects on neurons, immune and neuroendocrine cells through induction of de novo protein synthesis. In this study, we investigated, using mouse clonal anterior pituitary AtT20 D16:16 corticotrophs, whether (i) glucocorticoids rapidly inhibit glucose transport and (ii) whether this inhibition of glucose transport is directly correlated with early inhibition of ACTH secretion. Glucose uptake in AtT20 D16:16 cells was Na+-independent because the Na+-independent glucose transport inhibitor phloretin (100 microM) completely inhibited specific 14C-deoxygluose (DoG) uptake and replacement of extracellular Na+ with N-methyl D-glucamine+ had no effect. Furthermore, the Na+-independent glucose transporters, GLUTs 1 and 3 were expressed in AtT20 D16:16 cells. The synthetic type II glucocorticoid receptor agonist dexamethasone, rapidly, within 2 h, inhibited DoG uptake into AtT20 D16:16 cells through a mechanism that was dependent on de novo mRNA synthesis. Glucocorticoid inhibition of glucose transport was not correlated with early inhibition of ACTH secretion because removal of glucose from the external medium had no effect on CRF-stimulated ACTH secretion or the efficacy of early glucocorticoid inhibition of ACTH release. Although the Na+-independent glucose transport inhibitor phloretin significantly inhibited CRF-stimulated ACTH release, this effect of phloretin was a result of its potent activation of large conductance calcium-activated potassium (BK) channels. These data suggest that different molecular pathways and/or glucocorticoid induced proteins underlie the mechanism(s) of early glucocorticoid inhibition of glucose uptake and ACTH release, respectively.

Synergistic Activation of the Human Type II 3β-Hydroxysteroid Dehydrogenase/Δ5-Δ4 Isomerase Promoter by the Transcription Factor Steroidogenic Factor-1/Adrenal 4-binding Protein and Phorbol Ester

Steroidogenic factor-1/adrenal 4-binding protein (SF-1/Ad4BP) is an orphan nuclear receptor/transcription factor known to regulate the P450 steroid hydroxylases; however, mechanisms that regulate the activity of SF-1/Ad4BP are not well defined. In addition, little is known about the mechanisms that regulate the human steroidogenic enzyme, type II 3beta-hydroxysteroid dehydrogenase (3beta-HSD II), the major gonadal and adrenal isoform. Regulation of the 3beta-HSD II promoter was examined using human adrenal cortical (H295R; steroidogenic) and cervical (HeLa; non-steroidogenic) carcinoma cells. H295R cells were transfected with a series of 5' deletions of 1251 base pairs (bp) of the 3beta-HSD II 5'-flanking region fused to a chloramphenicol acetyltransferase (CAT) reporter gene followed by treatment with or without phorbol ester (phorbol 12-myristate 13-acetate; PMA). CAT assay data indicated that the region from -101 to -52 bp of the promoter was required for PMA-induced expression. A putative SF-1/Ad4BP regulatory element, TCAAGGTAA, was identified by sequence homology at -64 to -56 bp of the promoter. Cotransfection of HeLa cells with the -101 3beta-HSD-CAT construct and an expression vector for SF-1/Ad4BP increased CAT activity 49-fold. Subsequent treatment with PMA induced an unexpected synergistic increase in transcriptional activity 540-fold over basal. Mutation of the putative response element (TCAAGGTAA to TCAATTTAA) abolished SF-1-induced CAT activity and the synergistic response to PMA. Gel mobility shift assays confirmed that SF-1/Ad4BP interacts with the putative element and transcripts for SF-1/Ad4BP were detected in H295R cells by Northern analysis. These data are the first to demonstrate 1) regulation of a non-cytochrome P450 steroidogenic enzyme promoter by SF-1/Ad4BP, 2) a powerful synergistic effect of PMA on SF-1/Ad4BP-induced transcription, and 3) the importance of the SF-1/Ad4BP regulatory element in the regulation of the 3beta-HSD II promoter.