Elevated luteinizing hormone induces expression of its receptor and promotes steroidogenesis in the adrenal cortex

Is membrane androgen and estrogen receptor signaling imperative in the governing function of the adrenal cortex in the Eurasian beaver (Castor fiber L.)?

There is a need to fully know the physiology of Eurasian beaver due to its essential role in environmental homeostasis. However, a "human factor" impacts this, including stress conditions and environmental pollution. Adrenal glands protect these all. The regulation of endocrine processes by nonclassical androgen and estrogen signaling, the first and fastest control, is still a matter of research. The specific analyses performed here in mature female and male beaver adrenals contained: anatomical and histological examinations, expression and localization of membrane androgen receptor (zinc transporter, Zinc- and Iron-like protein 9; ZIP9) and membrane estrogen receptor coupled with G protein (GPER), and measurement of zinc (Zn2+) and copper (Ca2+) ion levels and corticosterone levels. We revealed normal anatomical localization, size, and tissue histology in female and male beavers, respectively. Equally, ZIP9 and GPER were localized in the membrane of all adrenal cortex cells. The protein expression of these receptors was higher (p < 0.001) in male than female adrenal cortex cells. Similarly, Zn2+ and Ca2+ ion levels were higher (p < 0.05, p < 0.01) in male than female adrenal cortex. The increased corticosterone levels (p < 0.001) were detected in the adrenal cortex of females when compared to males. The present study is the first to report the presence of nonclassical androgen and estrogen signaling and its possible regulatory function in the adrenal cortex of Eurasian beavers. We assume that this first-activated and fast-transmitted regulation can be important in the context of the effect of environmental physical and chemical stressors especially on adrenal cortex cells. The beaver adrenals may constitute an additional supplementary model for searching for universal mechanisms of adrenal cortex physiology and diseases.

Elevated luteinizing hormone receptor signaling or selenium treatment leads to comparable changes in adrenal cortex histology and androgen-AR/ZIP9 signaling

The importance and regulation of adrenal androgen production and signaling are not completely understood and are scarcely studied. In addition, there is still a search for appropriate animal models and experimental systems for the investigation of adrenal physiology and disease. Therefore, the main objective of the study was to evaluate the effect of luteinizing hormone (LH) signaling and selenium (Se2+) exposure on androgen adrenal signaling via canonical androgen receptor (AR), and membrane androgen receptor acting as zinc transporter (zinc- and iron-like protein 9; ZIP9). For herein evaluations, adrenals isolated from transgenic mice with elevated LH receptor signaling (KiLHRD582G) and adrenals obtained from rabbits used for ex vivo adenal cortex culture and exposure to Se2+ were utilized. Tissues were assessed for morphological, morphometric, and Western blot analyses and testosterone and zinc level measurements.Comparison of adrenal cortex histology and morphometric analysis in KiLHRD582G mice and Se2+-treated rabbits revealed cell hypertrophy. No changes in the expression of proliferating cell nuclear antigen (PCNA) were found. In addition, AR expression was decreased (p < 0.001) in both KiLHRD582G mouse and Se2+-treated rabbit adrenal cortex while expression of ZIP9 showed diverse changes. Its expression was increased (P < 0.001) in KiLHRD582G mice and decreased (P < 0.001) in Se2+-treated rabbits but only at the dose 10 ug/100 mg/ tissue. Moreover, increased testosterone levels (P < 0.05) and zinc levels were detected in the adrenal cortex of KiLHRD582G mice whereas in rabbit adrenal cortex treated with Se2+, the effect was the opposite (P < 0.001).

The mystery of transient pregnancy-induced cushing's syndrome: a case report and literature review highlighting GNAS somatic mutations and LHCGR overexpression

PURPOSE

Transient pregnancy-induced Cushing's syndrome is a rare condition characterized by the manifestation of symptoms solely during pregnancy, which typically resolve spontaneously following delivery or miscarriage. While it has been established that GNAS is associated with adrenal tumors, its specific role in the pathogenesis of pregnancy-induced Cushing's syndrome remains uncertain.This work aims to examine the association between GNAS mutation and pregnancy-induced Cushing's syndrome.

METHODS

DNA was extracted from patients' peripheral blood and tumor tissues for whole-exome sequencing (WES) and Sanger sequencing. We used AlphaFold to predict the protein structure of wild-type and mutant GNAS and to make functional predictions, and immunohistochemistry was used to detect disease-associated protein expression. A review and summary of reported cases of transient pregnancy-induced Cushing's syndrome induced by pregnancy was conducted.

RESULTS

Using WES, we identified a somatic mutation in GNAS (NM_000516, c.C601T, p.R201C) that was predicted to have a deleterious effect using computational methods, such as AlphaFold. Human chorionic gonadotropin (hCG) stimulation tests had weakly positive results, and immunohistochemical staining of adrenal adenoma tissue also revealed positivity for luteinizing hormone/chorionic gonadotropin receptor (LHCGR) and cytochrome P450 family 11 subfamily B member 1 (CYP11B1). We reviewed 15 published cases of transient Cushing's syndrome induced by pregnancy. Among these cases, immunohistochemical staining of the adrenal gland showed positive LHCGR expression in 3 case reports, similar to our findings.

CONCLUSION

Transient pregnancy-induced Cushing's syndrome may be associated with somatic GNAS mutations and altered adrenal pathology due to abnormal activation of LHCGR.

Current insight into the transient X-zone in the adrenal gland cortex

Mouse models have been widely used in the study of adrenal gland development and diseases. The X-zone is a unique structure of the mouse adrenal gland and lineage-tracing studies show that the X-zone is a remnant of the fetal adrenal cortex. Although the X-zone is considered analogous to the fetal zone in the human adrenal cortex, the functional significance of the X-zone has remained comparatively more obscure. The X-zone forms during the early postnatal stages of adrenal development and regresses later in a remarkable sexually dimorphic fashion. The formation and regression of the X-zone can be different in mice with different genetic backgrounds. Mouse models with gene mutations, hormone/chemical treatments, and/or gonadectomy can also display an aberrant development of the X-zone or alternatively a dysregulated X-zone regression. These models have shed light on the molecular mechanisms regulating the development and regression of these unique adrenocortical cells. This review paper briefly describes the development of the adrenal gland including the formation and regression processes of the X-zone. It also summarizes and lists mouse models that demonstrate different X-zone phenotypes.

The Effect of Statins on Male Reproductive Parameters: A Mechanism Involving Dysregulation of Gonadal Hormone Receptors and TRPV1

Statins have been shown to cause diverse male reproductive function impairment, and in some cases, orchialgia. Therefore, the current study investigated the possible mechanisms through which statins may alter male reproductive parameters. Thirty adult male Wistar rats (200-250 g) were divided into three groups. The animals were orally administered rosuvastatin (50 mg/kg), simvastatin (50 mg/kg), or 0.5% carboxy methyl cellulose (control), for a 30-day period. Spermatozoa were retrieved from the caudal epididymis for sperm analysis. The testis was used for all biochemical assays and immunofluorescent localization of biomarkers of interest. Rosuvastatin-treated animals presented with a significant decrease in sperm concentration when compared to both the control and simvastatin groups (p < 0.005). While no significant difference was observed between the simvastatin and the control group. The Sertoli cells, Leydig cells and whole testicular tissue homogenate expressed transcripts of solute carrier organic anion transporters (SLCO1B1 and SLCO1B3). There was a significant decrease in the testicular protein expression of the luteinizing hormone receptor, follicle stimulating hormone receptor, and transient receptor potential vanilloid 1 in the rosuvastatin and simvastatin-treated animals compared to the control. The expression of SLCO1B1, SLCO1B2, and SLCO1B3 in the different spermatogenic cells portray that un-bio transformed statin can be transported into the testicular microenvironment, which can subsequently alter the regulation of the gonadal hormone receptors, dysregulate pain-inflammatory biomarkers, and consequently impair sperm concentration.

Seasonal but not sex-biased gene expression of the carotenoid ketolase, CYP2J19, in the sexually dichromatic southern red bishop (Euplectes orix)

Intense red colours in birds are often owing to ketocarotenoids (KCs). In many land birds, KCs are oxidized from dietary yellow precursors, presumably by the avian carotenoid ketolase CYP2J19, the regulation and constraints of which have important implications for condition-dependence and honest signalling of carotenoid colour displays. We investigated hepatic CYP2J19 gene expression in the seasonally and sexually dichromatic southern red bishop (Euplectes orix) in relation to season, sex, progression of the prenuptial moult, testis size, body condition, redness and circulating sex steroids. A coloration function of CYP2J19 is supported by a seasonal upregulation prior to and during the carotenoid-depositing stage of the male prenuptial moult. However, CYP2J19 expression was similarly high in females (which do not moult prenuptially), and remained high in males after moult, suggesting additional or alternative roles of hepatic CYP2J19 or its products, such as detoxification or antioxidant functions. In males, the CYP2J19 upregulation preceded and was unrelated to the rise in plasma testosterone, but was correlated with androstenedione, probably of adrenal origin and compatible with luteinizing hormone-induced and (in females) oestrogen-suppressed moult. Finally, contrary to ideas that carotenoid ketolation rate mediates honest signalling of male quality, CYP2J19 expression was not related to plumage redness or male body condition.

Seasonal but not sex-biased gene expression of the carotenoid ketolase, CYP2J19, in the sexually dichromatic southern red bishop (Euplectes orix)

Intense red colours in birds are often owing to ketocarotenoids (KCs). In many land birds, KCs are oxidized from dietary yellow precursors, presumably by the avian carotenoid ketolase CYP2J19, the regulation and constraints of which have important implications for condition-dependence and honest signalling of carotenoid colour displays. We investigated hepatic CYP2J19 gene expression in the seasonally and sexually dichromatic southern red bishop (Euplectes orix) in relation to season, sex, progression of the prenuptial moult, testis size, body condition, redness and circulating sex steroids. A coloration function of CYP2J19 is supported by a seasonal upregulation prior to and during the carotenoid-depositing stage of the male prenuptial moult. However, CYP2J19 expression was similarly high in females (which do not moult prenuptially), and remained high in males after moult, suggesting additional or alternative roles of hepatic CYP2J19 or its products, such as detoxification or antioxidant functions. In males, the CYP2J19 upregulation preceded and was unrelated to the rise in plasma testosterone, but was correlated with androstenedione, probably of adrenal origin and compatible with luteinizing hormone-induced and (in females) oestrogen-suppressed moult. Finally, contrary to ideas that carotenoid ketolation rate mediates honest signalling of male quality, CYP2J19 expression was not related to plumage redness or male body condition.

Seasonal but not sex-biased gene expression of the carotenoid ketolase, CYP2J19, in the sexually dichromatic southern red bishop (Euplectes orix)

Intense red colours in birds are often owing to ketocarotenoids (KCs). In many land birds, KCs are oxidized from dietary yellow precursors, presumably by the avian carotenoid ketolase CYP2J19, the regulation and constraints of which have important implications for condition-dependence and honest signalling of carotenoid colour displays. We investigated hepatic CYP2J19 gene expression in the seasonally and sexually dichromatic southern red bishop (Euplectes orix) in relation to season, sex, progression of the prenuptial moult, testis size, body condition, redness and circulating sex steroids. A coloration function of CYP2J19 is supported by a seasonal upregulation prior to and during the carotenoid-depositing stage of the male prenuptial moult. However, CYP2J19 expression was similarly high in females (which do not moult prenuptially), and remained high in males after moult, suggesting additional or alternative roles of hepatic CYP2J19 or its products, such as detoxification or antioxidant functions. In males, the CYP2J19 upregulation preceded and was unrelated to the rise in plasma testosterone, but was correlated with androstenedione, probably of adrenal origin and compatible with luteinizing hormone-induced and (in females) oestrogen-suppressed moult. Finally, contrary to ideas that carotenoid ketolation rate mediates honest signalling of male quality, CYP2J19 expression was not related to plumage redness or male body condition.

Different expression of LHR, PRLR, GH and IGF1 during testicular development of yak

Luteinizing hormone receptor (LHR), prolactin receptor (PRLR), growth hormone (GH) and insulin-like growth factor 1 (IGF1) have been shown to be key regulators of germ cell development. However, the role of LHR, PRLR, GH and IGF1 in the development of yak testis remains unclear. In this study, we aimed to describe and compare gene expression and protein localization of LHR, PRLR, GH and IGF1 in the development of yak testes. Testes were collected from 6, 24, 36 and 72 months yak, and the kidney, liver, testicular, lung, skeletal muscle, heart and spleen tissues were collected from 36 months yak. The quantitative real-time PCR (qRT-PCR) results showed that the expression of these four genes was widely expressed in kidney, liver, testicular, lung, skeletal muscle, heart and spleen, while the LHR and PRLR were highly expressed in the kidney, skeletal muscle and testis, and higher levels of GH and IGF were expressed in spleen and testis. Moreover, the mRNA expression of these genes in adults was higher than in pre-pubertal yak. In the testis, the LHR-, PRLR-, GH- and IGF1-positive signals were detected in the Leydig cells of the 6 months, while the intense positive signals were discovered in Leydig cells, spermatogonia and spermatocytes of the 36 and 72 months. Thus, LHR, PRLR, GH and IGF1 may be involved in the development of spermatids and spermatocytes, and in the regulation of spermatogonia proliferation and Leydig cell function.

The invention of aldosterone, how the past resurfaces in pediatric endocrinology

Sodium and water homeostasis are drastically modified at birth, in mammals, by the transition from aquatic life to terrestrial life. Accumulating evidence during the past ten years underscores the central role for the mineralocorticoid signaling pathway, in the fine regulation of this equilibrium, at this critical period of development. Interestingly, regarding evolution, while the mineralocorticoid receptor is expressed in fish, the appearance of its related ligand, aldosterone, coincides with terrestrial life, as it is first detected in lungfish and amphibian. Thus, aldosterone is likely one of the main hormones regulating the transition from an aquatic environment to an air environment. This review will focus on the different actors of the mineralocorticoid signaling pathway from aldosterone secretion in the adrenal gland, to mineralocorticoid receptor expression in the kidney, summarizing their regulation and roles throughout fetal and neonatal development, in the light of evolution.

Impact of Clomiphene Citrate on the Steroid Profile in Dysmetabolic Men with Low Testosterone Levels

Clomiphene citrate (CC) in male hypogonadism increases testosterone (T) and estrogen levels by stimulating pituitary gonadotropin release. Our group confirmed these hormonal changes in a randomized, cross-over, double-blind trial of CC versus placebo in addition to metformin, conducted in 21 obese dysmetabolic men with low T levels. However, we hypothesize that based on its mechanism of action, CC may directly or indirectly affect adrenal steroidogenesis. The aim of this sub-study was to better understand the changes in steroid levels and metabolism induced by CC treatment. We assessed 17α-hydroxypregnelone (17αOH-P5), dehydroepiandrosterone (DHEA), progesterone (P4), 17α-hydroxyprogesterone (17αOH-P4), androstenedione (A), T, dihydrotestosterone (DHT), estrone (E1), 17β-estradiol (E2), 11-deoxycortisol (11 S), cortisol (F), and cortisone (E) by LC-MS/MS, and corticosteroid binding globulin (CBG) by ELISA, before and after each treatment. In addition, free-F and steroid product/precursor ratios were calculated. We observed a significant change in serum levels induced by CC compared with placebo for 17αOH-P4, DHT, T, E2, E1, F, E, and CBG, but not free-F. In addition, compared to placebo, CC induced higher 17αOH-P4/P4, E2/E1, 17αOH-P4/17αOH-P5, A/17αOH-P4, T/A, E1/A, F/11 S, and F/E ratios. Therefore, besides the CC stimulating effect on testis steroidogenesis, our study showed increased F, E, but not free-F, levels, indicating changes in steroid metabolism rather than adrenal secretion stimulation. The steroid profiling also revealed the CC stimulation of the Δ5 rather than the Δ4 pathway, thus indicating considerable testicular involvement in the increased androgen secretion.

Adrenal cortex stimulation with hCG in spayed female dogs with Cushing's syndrome: Is the LH-dependent variant possible?

Background:

The expression and overexpression of luteinizing hormone (LH) receptors in the canine adrenal gland cortex have been reported. Therefore, it was hypothesized that a LH-dependent form of Cushing’s syndrome (CS) could exist in dogs.

Aim:

To assess whether the adrenal gland post-ovariectomy (OVx) exhibits a greater response to adrenocorticotrophin (ACTH) stimulation; to evaluate whether the adrenal gland responds to human chorionic gonadotropin (hCG) stimulation by increasing the release of cortisol; and to consider whether hCG stimulus testing would be useful as a diagnosis for possible cases of LH-dependent CS.

Methods:

Cortisol concentrations were measured from healthy female dogs (n=16) at baseline and following ACTH stimulation before and 2 months after gonadectomy (OVx). Cortisol concentrations were also measured for female dogs with CS (n = 14) following administration of hCG (5000 IU). A post-hCG cortisol concentration greater than 140 nmol/l was used to define dogs with LH-dependent Cushing’s syndrome.

Results:

In normal female dogs, both pre- and post-stimulation cortisol concentrations increased following OVx (p = 0.002 and p = 0.0003, respectively). In female dogs with CS, cortisol concentrations increased following stimulation with hCG in 57% (8/14; p = 0.002). Age at the time of OVx was associated (p = 0.015) with the cortisol response to hCG [8 (5–9) years vs. 3.5 (2–6) years, p = 0.0013).

Conclusion:

Based on these results, an LH-dependent form of CS occurs in spayed female dogs, and that it is more likely to occur when female dogs are spayed later in life.

Hypogonadism induced by surgical stress and brain trauma is reversed by human chorionic gonadotropin in male rats: A potential therapy for surgical and TBI-induced hypogonadism?

INTRODUCTION

Hypogonadotropic hypogonadism (HH) is an almost universal, yet underappreciated, endocrinological complication of traumatic brain injury (TBI). The goal of this study was to determine whether the developmental hormone human chorionic gonadotropin (hCG) treatment could reverse HH induced by a TBI.

METHODS

Plasma samples were collected at post-surgery/post-injury (PSD/PID) days -10, 1, 11, 19 and 29 from male Sprague-Dawley rats (5- to 6-month-old) that had undergone a Sham surgery (craniectomy alone) or CCI injury (craniectomy + bilateral moderate-to-severe CCI injury) and treatment with saline or hCG (400 IU/kg; i.m.) every other day.

RESULTS

Both Sham and CCI injury significantly decreased circulating testosterone (T), 11-deoxycorticosterone (11-DOC) and corticosterone concentrations to a similar extent (79.1% vs. 80.0%; 46.6% vs. 48.4%; 56.2% vs. 32.5%; respectively) by PSD/PID 1. hCG treatment  returned circulating T to baseline concentrations by PSD/PID 1 (8.9 ± 1.5 ng/ml and 8.3 ± 1.9 ng/ml; respectively) and was maintained through PSD/PID 29. hCG treatment significantly, but transiently, increased circulating progesterone (P4) ~3-fold (30.2 ± 10.5 ng/ml and 24.2 ± 5.8 ng/ml) above that of baseline concentrations on PSD 1 and PID 1, respectively. hCG treatment did not reverse hypoadrenalism following either procedure.

CONCLUSIONS

Together, these data indicate that (1) craniectomy is sufficient to induce persistent hypogonadism and hypoadrenalism, (2) hCG can reverse hypogonadism induced by a craniectomy or craniectomy +CCI injury, suggesting that (3) craniectomy and CCI injury induce a persistent hypogonadism by decreasing hypothalamic and/or pituitary function rather than testicular function in male rats. The potential role of hCG as a cheap, safe and readily available treatment for reversing surgery or TBI-induced hypogonadism is discussed.

Recent advances in understanding gonadotropin signaling

Gonadotropins are glycoprotein sex hormones regulating development and reproduction and bind to specific G protein–coupled receptors expressed in the gonads. Their effects on multiple signaling cascades and intracellular events have recently been characterized using novel technological and scientific tools. The impact of allosteric modulators on gonadotropin signaling, the role of sugars linked to the hormone backbone, the detection of endosomal compartments supporting signaling modules, and the dissection of different effects mediated by these molecules are areas that have advanced significantly in the last decade. The classic view providing the exclusive activation of the cAMP/protein kinase A (PKA) and the steroidogenic pathway by these hormones has been expanded with the addition of novel signaling cascades as determined by high-resolution imaging techniques. These new findings provided new potential therapeutic applications. Despite these improvements, unanswered issues of gonadotropin physiology, such as the intrinsic pro-apoptotic potential to these hormones, the existence of receptors assembled as heteromers, and their expression in extragonadal tissues, remain to be studied. Elucidating these issues is a challenge for future research.

Stem cell function and plasticity in the normal physiology of the adrenal cortex

The adrenal cortex functions to produce steroid hormones necessary for life. To maintain its functional capacity throughout life, the adrenal cortex must be continually replenished and rapidly repaired following injury. Moreover, the adrenal responds to endocrine-mediated organismal needs, which are highly dynamic and necessitate a precise steroidogenic response. To meet these diverse needs, the adrenal employs multiple cell populations with stem cell function. Here, we discuss the literature on adrenocortical stem cells using hematopoietic stem cells as a benchmark to examine the functional capacity of particular cell populations, including those located in the capsule and peripheral cortex. These populations are coordinately regulated by paracrine and endocrine signaling mechanisms, and display remarkable plasticity to adapt to different physiological and pathological conditions. Some populations also exhibit sex-specific activity, which contributes to highly divergent proliferation rates between sexes. Understanding mechanisms that govern adrenocortical renewal has broad implications for both regenerative medicine and cancer.

An alternative theory for hormone effects on sex differences in PTSD: The role of heightened sex hormones during trauma

Women are at least twice as susceptible to developing post-traumatic stress disorder (PTSD) compared to men. Although most research seeking to explain this discrepancy has focussed on the role of oestradiol during fear extinction learning, the role of progesterone has been overlooked, despite relatively consistent findings being reported concerning the role of progesterone during consolidation of emotional and intrusive memories. In this review article, we outline literature supporting the role of progesterone on memory formation, with particular emphasis on potential memory-enhancing properties of progesterone when subjects are placed under stress. It is possible that progesterone directly and indirectly exerts memory-enhancing effects at the time of trauma, which is an effect that may not be necessarily captured during non-stressful paradigms. We propose a model whereby progesterone's steroidogenic relationship to cortisol and brain-derived neurotrophic factor in combination with elevated oestradiol may enhance emotional memory consolidation during trauma and therefore present a specific vulnerability to PTSD formation in women, particularly during the mid-luteal phase of the menstrual cycle.

Effect of photoperiod on ovarian morphology, reproductive hormone secretion, and hormone receptor mRNA expression in layer ducks during the pullet phase

We evaluated the effect of photoperiod on ovarian morphology, reproductive hormone secretion, and hormone receptor mRNA expression in layer ducks during the pullet phase. A total of 480 71-d-old Jinding layer ducks were randomly divided into 5 groups that received 6L (hours of light):18D (hours of darkness), 8L:16D, 10L:14D, 12L:12D, or 14L:10D, respectively. Each group had 6 replicates with 16 birds each. The photoperiod feeding trial lasted 80 d until 150 d of age. The age at first egg (AFE), the total number, and weight of eggs increased linearly with increasing photoperiods (P < 0.05); lower values of AFE occurred with photoperiods ≥8 h, whereas a higher total number and weight of eggs occurred with photoperiods ≥10 h, compared with 6L:18D (P > 0.05). Oviduct weight, ovary percentage, and initial and bare stroma (weight and percentage) increased quadratically with increasing photoperiods (P < 0.05), and 10.24, 10.01, and 10.10 h were the optimal photoperiods for oviduct weight, bare stroma (follicles ≥2 mm in diameter removed) weight, and bare stroma percentage, respectively, as calculated from reliable regression equations (R2 ≥ 0.5791). Compared with 6L:18D, 10L:14D had a higher total large white follicle weight, small yellow follicle number, and weight (P < 0.05). In addition, higher serum levels of follicle-stimulating hormone, luteinizing hormone, and progesterone were observed with ≥10-h photoperiods (P < 0.05), as were levels of hormone receptor mRNA expression in ovarian follicles (P < 0.05), with the highest values for both measures at 10L:14D. In the hypothalamus, mRNA expression of gonadotropin-releasing hormone increased in ≥8-h photoperiods, with the highest value at 10L:14D. In contrast, gonadotropin-inhibitory hormone increased in photoperiods ≥12 h (P < 0.05). In conclusion, an appropriate photoperiod led to early sexual maturity and improved the development of reproductive organs and ovarian follicles through effects on reproductive hormones and their receptors; 10 to 10.24 h is an adequate photoperiod for layer ducks during the pullet phase.

The transient cortical zone in the adrenal gland: the mystery of the adrenal X-zone

The X-zone is a transient cortical region enriched in eosinophilic cells located in the cortical-medullary boundary of the mouse adrenal gland. Similar to the X-zone, the fetal zone in human adrenals is also a transient cortical compartment, comprising the majority of the human fetal adrenal gland. During adrenal development, fetal cortical cells are gradually replaced by newly formed adult cortical cells that develop into outer definitive zones. In mice, the regression of this fetal cell population is sexually dimorphic. Many mouse models with mutations associated with endocrine factors have been reported with X-zone phenotypes. Increasing findings indicate that the cell fate of this aged cell population of the adrenal cortex can be manipulated by many hormonal and nonhormonal factors. This review summarizes the current knowledge of this transient adrenocortical zone with an emphasis on genes and signaling pathways that affect X-zone cells.

Two Hormones for One Receptor: Evolution, Biochemistry, Actions, and Pathophysiology of LH and hCG

LH and chorionic gonadotropin (CG) are glycoproteins fundamental to sexual development and reproduction. Because they act on the same receptor (LHCGR), the general consensus has been that LH and human CG (hCG) are equivalent. However, separate evolution of LHβ and hCGβ subunits occurred in primates, resulting in two molecules sharing ~85% identity and regulating different physiological events. Pituitary, pulsatile LH production results in an ~90-minute half-life molecule targeting the gonads to regulate gametogenesis and androgen synthesis. Trophoblast hCG, the "pregnancy hormone," exists in several isoforms and glycosylation variants with long half-lives (hours) and angiogenic potential and acts on luteinized ovarian cells as progestational. The different molecular features of LH and hCG lead to hormone-specific LHCGR binding and intracellular signaling cascades. In ovarian cells, LH action is preferentially exerted through kinases, phosphorylated extracellular-regulated kinase 1/2 (pERK1/2) and phosphorylated AKT (also known as protein kinase B), resulting in irreplaceable proliferative/antiapoptotic signals and partial agonism on progesterone production in vitro. In contrast, hCG displays notable cAMP/protein kinase A (PKA)-mediated steroidogenic and proapoptotic potential, which is masked by estrogen action in vivo. In vitro data have been confirmed by a large data set from assisted reproduction, because the steroidogenic potential of hCG positively affects the number of retrieved oocytes, and LH affects the pregnancy rate (per oocyte number). Leydig cell in vitro exposure to hCG results in qualitatively similar cAMP/PKA and pERK1/2 activation compared with LH and testosterone. The supposed equivalence of LH and hCG has been disproved by such data, highlighting their sex-specific functions and thus deeming it an oversight caused by incomplete understanding of clinical data.

Effect of ACTH and hCG on the Expression of Gonadotropin-Inducible Ovarian Transcription Factor 1 (Giot1) Gene in the Rat Adrenal Gland

Gonadotropin-inducible ovarian transcription factor-1 (Giot1) belongs to a family of fast-responsive genes, and gonadotropins rapidly induce its expression in steroidogenic cells of ovaries and testes of rats. Gonadal Giot1 gene expression is regulated by cyclic adenosine monophosphate (cAMP) -dependent protein kinase A pathway, with essential role of orphan nuclear receptor NR4A1 transcription factor (nuclear receptor subfamily 4, group A, member 1). A recent study reports that Giot1 is also expressed in adrenals, however, the mechanism of its regulation in adrenal gland is yet to be identified. Therefore, the aim of this study was to characterise the changes in Giot1 gene expression in male and female rat adrenals using wide range of in vivo and in vitro experimental models. Special emphasis was directed at the Giot1 gene regulation by ACTH and gonadotropin. In our study, we found that ACTH rapidly stimulates Giot1 expression both in vivo and in vitro. However, gonadotropin does not affect the adrenal Giot1 gene expression, presumably due to the low expression of gonadotropin receptor in adrenals. Both testosterone and estradiol administered in vivo had inhibitory effect on Giot1 gene expression in the adrenals of post-gonadectomized adult rats. Further, our studies revealed that the intracellular mechanism of Giot1 gene regulation in rat adrenals is similar to that of gonads. As in the case of gonads, the expression of Giot1 in adrenal gland is regulated by cAMP-dependent signaling pathway with essential role of the NR4A1 transcription factor. The results of our studies suggest that Giot1 may be involved in the regulation of rat adrenocortical steroidogenesis.

Mouse models for the analysis of gonadotropin secretion and action

Gonadotropins are pituitary gonadotrope-derived glycoprotein hormones. They act by binding to G-protein coupled receptors on gonads. Gonadotropins play critical roles in reproduction by regulating both gametogenesis and steroidogenesis. Although biochemical and physiological studies provided a wealth of knowledge, gene manipulation techniques using novel mouse models gave new insights into gonadotropin synthesis, secretion and action. Both gain of function and loss of function mouse models for understanding gonadotropin action in a whole animal context have already been generated. Moreover, recent studies on gonadotropin actions in non-gonadal tissues challenged the central dogma of classical gonadotropin actions in gonads and revealed new signaling pathways in these non-gonadal tissues. In this Chapter, we have discussed our current understanding of gonadotropin synthesis, secretion and action using a variety of genetically engineered mouse models.

Luteinizing hormone and insulin resistance in menopausal patients with adrenal incidentalomas: The cause-effect relationship?

OBJECTIVE

A high prevalence of insulin resistance (IR) has proven to manifest in patients with adrenal incidentalomas (AI). It has been demonstrated that an increase in IR is related to the size of tumourous masses; additionally, luteinizing hormone (LH)-dependent adrenal pathologies are well documented in patients with LH-responsive adrenal tumours occurring under conditions of physiologically elevated LH. We hypothesized that an association between LH and insulin might play a role in adrenal tumourigenesis and steroidogenesis.

DESIGN

The aim of our study was to investigate the association between LH and IR; adrenal tumour size (ATS) and IR; LH and cortisol after the 1 mg overnight dexamethasone test (1 mg DST); and ATS and 1 mg DST cortisol in AI patients. This was a case-control study conducted in the Clinic for Endocrinology, Diabetes and Metabolic Diseases in Belgrade, Serbia. The total study group consisted of 105 menopausal women: 75 AI patients [27 with nonfunctional AI (NAI) and 48 with (possible) autonomous cortisol secretion ((P)ACS)] and 30 age-, BMI-, LH- and menopause duration-matched healthy control (HC) women. To estimate IR, we used homeostasis model assessment (HOMA-IR).

RESULTS

Luteinizing hormone and ATS are in a significant positive correlation with HOMA-IR and 1 mg DST cortisol in menopausal patients with AI and (P)ACS.

CONCLUSIONS

Our data point to a possible cause-effect relationship between LH and insulin in patients with AI and (P)ACS adding to the body of evidence of their involvement in adrenal tumourigenesis and steroidogenesis.

Successful Treatment of Estrogen Excess in Primary Bilateral Macronodular Adrenocortical Hyperplasia with Leuprolide Acetate

Primary bilateral macronodular adrenocortical hyperplasia (PBMAH) is an uncommon cause of adrenal Cushing syndrome (CS) in which cortisol and occasionally other steroid hormones can be secreted under the influence of aberrantly expressed G-protein coupled receptors (GPCRs) in the adrenal cortex. We describe the unique case of a 64-year-old postmenopausal female with PBMAH whose adrenal lesions expressed luteinizing hormone receptors (LHr). She presented initially with CS and underwent right adrenalectomy; a few years later she presented with macromastia and mastodynia, possibly due to estrogen excess from her remaining left adrenocortical masses. Testing before and after treatment with quarterly leuprolide acetate therapy and immunohistochemistry on tissue and targeted sequencing of the genes of interest were performed. Tissue from the patient's right adrenal was tested for P450 aromatase (CYP19A1) and LHr expression; both were expressed throughout the hyperplastic cortex, although expression was more intense in the adenomatous areas. Targeted sequencing revealed a pathogenic PDE11A mutation, as well as variants in the ARMC5 and INHA genes. PDE11A expression was decreased in the adenoma but there was no loss of heterozygosity for the PDE11A locus. Because of the clinical presentation and LHr expression, quarterly leuprolide acetate therapy was started. Shortly after initiation of therapy, the patient reported decreased breast size and pain; she remains well controlled to date, after 10 years of treatment. This is the first description of a patient with PBMAH presenting with severe macromastia and mastodynia from what appears to be excess estrogen production from her adrenal tumor. The patient had a long-lasting response to chronic leuprolide acetate treatment, showing that drug therapy exploiting the aberrant receptor expression in PBMAH is possible even in the absence of cortisol overproduction.

Novel genes involved in pathophysiology of gonadotropin-dependent adrenal tumors in mice

Specific inbred strains and transgenic inhibin-α Simian Virus 40 T antigen (inhα/Tag) mice are genetically susceptible to gonadectomy-induced adrenocortical neoplasias. We identified altered gene expression in prepubertally gonadectomized (GDX) inhα/Tag and wild-type (WT) mice. Besides earlier reported Gata4 and Lhcgr, we found up-regulated Esr1, Prlr-rs1, and down-regulated Grb10, Mmp24, Sgcd, Rerg, Gnas, Nfatc2, Gnrhr, Igf2 in inhα/Tag adrenal tumors. Sex-steroidogenic enzyme genes expression (Srd5a1, Cyp19a1) was up-regulated in tumors, but adrenal-specific steroidogenic enzyme (Cyp21a1, Cyp11b1, Cyp11b2) down-regulated. We localized novel Lhcgr transcripts in adrenal cortex parenchyma and in non-steroidogenic A cells, in GDX WT and in intact WT mice. We identified up-regulated Esr1 as a potential novel biomarker of gonadectomy-induced adrenocortical tumors in inhα/Tag mice presenting with an inverted adrenal-to-gonadal steroidogenic gene expression profile. A putative normal adrenal remodeling or tumor suppressor role of the down-regulated genes (e.g. Grb10, Rerg, Gnas, and Nfatc2) in the tumors remains to be addressed.

Sex differences in variability across timescales in BALB/c mice

BACKGROUND

Females are markedly underinvestigated in the biological and behavioral sciences due to the presumption that cyclic hormonal changes across the ovulatory cycle introduce excess variability to measures of interest in comparison to males. However, recent analyses indicate that male and female mice and rats exhibit comparable variability across numerous physiological and behavioral measures, even when the stage of the estrous cycle is not considered. Hormonal changes across the ovulatory cycle likely contribute cyclic, intra-individual variability in females, but the source(s) of male variability has, to our knowledge, not been investigated. It is unclear whether male variability, like that of females, is temporally structured and, therefore, quantifiable and predictable. Finally, whether males and females exhibit variability on similar time scales has not been explored.

METHODS

These questions were addressed by collecting chronic, high temporal resolution locomotor activity (LA) and core body temperature (CBT) data from male and female BALB/c mice.

RESULTS

Contrary to expectation, males are more variable than females over the course of the day (diel variability) and exhibit higher intra-individual daily range than females in both LA and CBT. Between mice of a given sex, variability is comparable for LA but the inter-individual daily range in CBT is greater for males. To identify potential rhythmic processes contributing to these sex differences, we employed wavelet transformations across a range of periodicities (1-39 h).

CONCLUSIONS

Although variability in circadian power is comparable between the sexes for both LA and CBT, infradian variability is greater in females and ultradian variability is greater in males. Thus, exclusion of female mice from studies because of estrous cycle variability may increase variance in investigations where only male measures are collected over a span of several hours and limit generalization of findings from males to females.

Functional Implications of LH/hCG Receptors in Pregnancy-Induced Cushing Syndrome

Context:

Elevated human choriogonadotropin (hCG) may stimulate aberrantly expressed luteinizing hormone (LH)/hCG receptor (LHCGR) in adrenal glands, resulting in pregnancy-induced bilateral macronodular adrenal hyperplasia and transient Cushing syndrome (CS).

Objective:

To determine the role of LHCGR in transient, pregnancy-induced CS.

Design, Setting, Patient, and Intervention:

We investigated the functional implications of LHCGRs in a patient presenting, at a tertiary referral center, with repeated pregnancy-induced CS with bilateral adrenal hyperplasia, resolving after parturition.

Main Outcome Measures and Results:

Acute testing for aberrant hormone receptors was negative except for arginine vasopressin (AVP)–increased cortisol secretion. Long-term hCG stimulation induced hypercortisolism, which was unsuppressed by dexamethasone. Postadrenalectomy histopathology demonstrated steroidogenically active adrenocortical hyperplasia and ectopic cortical cell clusters in the medulla. Quantitative polymerase chain reaction showed upregulated expression of LHCGR, transcription factors GATA4, ZFPM2, and proopiomelanocortin (POMC), AVP receptors (AVPRs) AVPR1A and AVPR2, and downregulated melanocortin 2 receptor (MC2R) vs control adrenals. LHCGR was localized in subcapsular, zona glomerulosa, and hyperplastic cells. Single adrenocorticotropic hormone–positive medullary cells were demonstrated in the zona reticularis. The role of adrenal adrenocorticotropic hormone was considered negligible due to downregulated MC2R. Coexpression of CYP11B1/CYP11B2 and AVPR1A/AVPR2 was observed in ectopic cortical cells in the medulla. hCG stimulation of the patient’s adrenal cell cultures significantly increased cyclic adenosine monophosphate, corticosterone, 11-deoxycortisol, cortisol, and androstenedione production. CTNNB1, PRKAR1A, ARMC5, and PRKACA gene mutational analyses were negative.

Conclusion:

Nongenetic, transient, somatic mutation-independent, pregnancy-induced CS was due to hCG-stimulated transformation of LHCGR-positive undifferentiated subcapsular cells (presumably adrenocortical progenitors) into LHCGR-positive hyperplastic cortical cells. These cells respond to hCG stimulation with cortisol secretion. Without the ligand, they persist with aberrant LHCGR expression and the ability to respond to the same stimulus.

Mouse Models for the Study of Synthesis, Secretion, and Action of Pituitary Gonadotropins

Gonadotropins play fundamental roles in reproduction. More than 30years ago, Cga transgenic mice were generated, and more than 20years ago, the phenotypes of Cga null mice were reported. Since then, numerous mouse strains have been generated and characterized to address several questions in reproductive biology involving gonadotropin synthesis, secretion, and action. More recently, extragonadal expression, and in some cases, functions of gonadotropins in nongonadal tissues have been identified. Several genomic and proteomic approaches including novel mouse genome editing tools are available now. It is anticipated that these and other emerging technologies will be useful to build an integrated network of gonadotropin signaling pathways in various tissues. Undoubtedly, research on gonadotropins will continue to provide new knowledge and allow us transcend from benchside to the bedside.

Virilizing oncocytic adrenocortical carcinoma: clinical and immunohistochemical studies

CONTEXT

Oncocytic tumors of the adrenal cortex are rare, mostly nonfunctioning and benign.

SETTING

Report virilizing oncocytic adrenocortical carcinoma in a 50-year-old woman.

PATIENT

She presented a recent and progressive virilization syndrome, associated with high blood pressure. Hormonal evaluation showed elevated serum testosterone and delta-4-androstenedione levels, normal urinary free cortisol level and incomplete suppression of cortisol at the 1 mg dexamethasone suppression test. CT scan of the abdomen revealed a 35 mm left adrenal mass.

INTERVENTION

The patient underwent a left adrenalectomy, and the histological study showed a 3 cm oncocytic adrenocortical carcinoma with signs of malignancy.

RESULTS

Immunohistochemical study revealed that tumor cells expressed the steroidogenic enzymes involved into androgen synthesis (3βHSD and P450c17α), P450 aromatase and luteinizing hormone (LH) receptors. Post-operatively, signs of virilization improved rapidly, serum testosterone and delta-4-androstenedione levels returned to normal, as did the dexamethasone suppression test. During follow-up CT-scan and 18-FDG PET/CT showed a right ovary mass, corresponding to a follicular cyst associated with hyperthecosis. The patient is alive with no recurrence 48 months after adrenal surgery.

CONCLUSION

Oncocytic adrenocortical carcinomas, although extremely rare, should be considered in women with a virilization syndrome. In this woman immunohistochimical studies revealed the presence of steroidogenic enzymes involved into androgen synthesis and aromatization, and LH receptors could be implicated in this pathology.

Multiple aberrant hormone receptors in Cushing's syndrome

The mechanisms regulating cortisol production when ACTH of pituitary origin is suppressed in primary adrenal causes of Cushing's syndrome (CS) include diverse genetic and molecular mechanisms. These can lead either to constitutive activation of the cAMP system and steroidogenesis or to its regulation exerted by the aberrant adrenal expression of several hormone receptors, particularly G-protein coupled hormone receptors (GPCR) and their ligands. Screening for aberrant expression of GPCR in bilateral macronodular adrenal hyperplasia (BMAH) and unilateral adrenal tumors of patients with overt or subclinical CS demonstrates the frequent co-expression of several receptors. Aberrant hormone receptors can also exert their activity by regulating the paracrine secretion of ACTH or other ligands for those receptors in BMAH or unilateral tumors. The aberrant expression of hormone receptors is not limited to adrenal CS but can be implicated in other endocrine tumors including primary aldosteronism and Cushing's disease. Targeted therapies to block the aberrant receptors or their ligands could become useful in the future.

Steroidogenic organ development and homeostasis: A WT1-centric view

Adrenal and gonads are the main steroidogenic organs and are central to regulate body homeostasis in the vertebrate organism. Although adrenals and gonads are physically separated in the adult organism, both organs share a common developmental origin, the adrenogonadal primordium. One of the key genes involved in the development of both organs is the Wilms' tumor suppressor WT1, which encodes a zinc finger protein that has fascinated the scientific community for more than two decades. This review will provide an overview of the processes leading to the development of these unique organs with a particular focus on the multiple functions WT1 serves during adrenogonadal development. In addition, we will highlight some recent findings and open questions on how maintenance of steroidogenic organs is achieved in the adult organism.

Low temperature-induced circulating triiodothyronine accelerates seasonal testicular regression

In temperate zones, animals restrict breeding to specific seasons to maximize the survival of their offspring. Birds have evolved highly sophisticated mechanisms of seasonal regulation, and their testicular mass can change 100-fold within a few weeks. Recent studies on Japanese quail revealed that seasonal gonadal development is regulated by central thyroid hormone activation within the hypothalamus, depending on the photoperiodic changes. By contrast, the mechanisms underlying seasonal testicular regression remain unclear. Here we show the effects of short day and low temperature on testicular regression in quail. Low temperature stimulus accelerated short day-induced testicular regression by shutting down the hypothalamus-pituitary-gonadal axis and inducing meiotic arrest and germ cell apoptosis. Induction of T3 coincided with the climax of testicular regression. Temporal gene expression analysis over the course of apoptosis revealed the suppression of LH response genes and activation of T3 response genes involved in amphibian metamorphosis within the testis. Daily ip administration of T3 mimicked the effects of low temperature stimulus on germ cell apoptosis and testicular mass. Although type 2 deiodinase, a thyroid hormone-activating enzyme, in the brown adipose tissue generates circulating T3 under low-temperature conditions in mammals, there is no distinct brown adipose tissue in birds. In birds, type 2 deiodinase is induced by low temperature exclusively in the liver, which appears to be caused by increased food consumption. We conclude that birds use low temperature-induced circulating T3 not only for adaptive thermoregulation but also to trigger apoptosis to accelerate seasonal testicular regression.

Genetic Models for the Study of Luteinizing Hormone Receptor Function

The luteinizing hormone/chorionic gonadotropin receptor (LHCGR) is essential for fertility in men and women. LHCGR binds luteinizing hormone (LH) as well as the highly homologous chorionic gonadotropin. Signaling from LHCGR is required for steroidogenesis and gametogenesis in males and females and for sexual differentiation in the male. The importance of LHCGR in reproductive physiology is underscored by the large number of naturally occurring inactivating and activating mutations in the receptor that result in reproductive disorders. Consequently, several genetically modified mouse models have been developed for the study of LHCGR function. They include targeted deletion of LH and LHCGR that mimic inactivating mutations in hormone and receptor, expression of a constitutively active mutant in LHCGR that mimics activating mutations associated with familial male-limited precocious puberty and transgenic models of LH and hCG overexpression. This review summarizes the salient findings from these models and their utility in understanding the physiological and pathological consequences of loss and gain of function in LHCGR signaling.

Adrenocortical production is associated with higher levels of luteinizing hormone in nonobese women with polycystic ovary syndrome

Objective. Insulin resistance (IR) and ovarian and adrenal hyperandrogenism are a common finding in women with polycystic ovary syndrome (PCOS). The aim of the present study was to access possible differences in insulin resistance, gonadotropins, and androgens production in obese and nonobese PCOS women. Study Design. We studied 37 PCOS women (16 nonobese and 21 obese) and 18 nonobese controls. Fasting glucose, insulin, androgens, and gonadotropins levels were determined. Salivary cortisol was measured basal and in the morning after dexamethasone (DEX) 0.25 mg. Results. Nonobese PCOS women showed higher basal salivary cortisol and serum dehydroepiandrosterone sulfate and luteinizing hormone (LH) levels than controls and obese PCOS. These hormones levels did not differ between the obese and control groups. After DEX administration no differences were found between the three groups. In PCOS women, salivary cortisol levels showed negative correlation with BMI (r = -0.52; P = 0.001) and insulin (r = -0.47; P = 0.003) and positive correlation with LH (r = 0.40; P = 0.016). Conclusion. Our results show an increased adrenocortical production in nonobese PCOS women, not related to IR and associated with a normal hypothalamic-pituitary-adrenal suppression. Higher LH levels might be involved in this event.

WT1 maintains adrenal-gonadal primordium identity and marks a population of AGP-like progenitors within the adrenal gland

Adrenal glands and gonads share a common primordium (AGP), but the molecular events driving differentiation are poorly understood. Here we demonstrate that the Wilms tumor suppressor WT1 is a key factor defining AGP identity by inhibiting the steroidogenic differentiation process. Indeed, ectopic expression of WT1 precludes differentiation into adrenocortical steroidogenic cells by locking them into a progenitor state. Chromatin immunoprecipitation experiments identify Tcf21 and Gli1 as direct targets of WT1. Moreover, cell lineage tracing analyses identify a long-living progenitor population within the adrenal gland, characterized by the expression of WT1, GATA4, GLI1, and TCF21, that can generate steroidogenic cells in vivo. Strikingly, gonadectomy dramatically activates these WT1(+) cells and leads to their differentiation into gonadal steroidogenic tissue. Thus, our data describe a mechanism of response to organ loss by recreating hormone-producing cells at a heterotopic site.

The permissive role of prolactin as a regulator of luteinizing hormone action in the female mouse ovary and extragonadal tumorigenesis

Transgenic female mice overexpressing the hCGβ subunit (hCGβ(+)) and producing elevated levels of luteinizing hormone (LH)/hCG bioactivity present as young adults with enhanced ovarian steroidogenesis, precocious puberty, and infertility. They subsequently develop pituitary prolactinomas, high circulating prolactin (PRL) levels, and marked mammary gland lobuloalveolar development followed by adenocarcinomas. None of these phenotypes appear in gonadectomized mice, indicating that the hCG-induced aberrations of ovarian function are responsible for the extragonadal phenotypes. PRL receptor-deficient (PRLR(-/-)) female mice are sterile, despite ovulating, due to a failure of embryo implantation, as a consequence of decreased ovarian LH receptor (Lhcgr) expression and inadequate corpus luteum formation and progesterone production. To study further the presumed permissive role of PRL in the maintenance of gonadal responsiveness to LH/hCG stimulation, we crossed the hCGβ(+) and PRLR(-/-) mice. The double-mutant hCGβ(+)/PRLR(-/-) females remained sterile with an ovarian phenotype similar to PRLR(-/-) mice, indicating that LH action, Lhcgr expression, and consequent luteinization are not possible without simultaneous PRL signaling. The high frequency of pituitary prolactinomas in PRLR(-/-) mice was not affected by transgenic hCGβ expression. In contrast, none of the hCGβ(+)/PRLR(-/-) females showed either mammary gland lobuloalveolar development or tumors, and the increased mammary gland Wnt-5b expression, possibly responsible for the tumorigenesis in hCGβ(+) mice, was absent in double-mutant mice. Hence, high LH/hCG stimulation is unable to compensate for missing PRL signaling in the maintenance of luteal function. PRL thus appears to be a major permissive regulator of LH action in the ovary and of its secondary extragonadal effects.

Transgenic GATA-4 expression induces adrenocortical tumorigenesis in C57Bl/6 mice

A link between elevated luteinizing hormone (LH) levels, GATA-4 and LH receptor (LHCGR) expression and gonadotropin-dependent adrenocortical tumorigenesis in humans and mice has been shown. To assess the mechanistic tumorigenic interrelationships between these factors, we transgenically expressed Gata4 under the 21-hydroxylase promoter (Cyp21a1, 21-OH) in C57Bl/6N mice. There was a gradual age-dependent increase of GATA-4 expression only in 21-OH-GATA-4 (TG) female adrenals, in association with slowly progressing neoplasia of non-steroidogenic spindle-shaped A cells in the subcapsular cortex. Gonadectomy (GDX), apparently through direct action of elevated serum LH, markedly enhanced the adrenocortical neoplasia, which now also appeared in GDX TG males. The neoplastic areas of the post-GDX TG adrenals contained, besides A cells, larger lipid-laden, steroidogenically active and LHCGR-positive B cells. Prolonged (>10 months) exposure to elevated post-GDX LH levels resulted in formation of adrenocortical adenomas in the TG mice. Intact and GDX TG mouse adrenals displayed elevated FOG-2 and decreased GATA-6 expression. Additionally, increased expression/activation of components of the Inhbb-Acvr2a-Acvr1c-Smad2/3 signaling system was observed in 12-month-old GDX TG adrenals. Our findings show that two distinct GATA-4-dependent populations of neoplastic adrenocortical cells form: non-steroidogenic LH-independent A cells and steroidogenic LH-dependent B cells.

Mouse testis development and function are differently regulated by follicle-stimulating hormone receptors signaling during fetal and prepubertal life

It is currently admitted that Follicle-Stimulating Hormone (FSH) is physiologically involved in the development and function of fetal/neonatal Sertoli cells in the rat but not the mouse. However, FSH is produced by both species from late fetal life onwards. We thus reinvestigated the role of FSH in mouse testis development at day 0 (birth) 6, 8 and 10 post-partum (dpp) by using mice that lack functional FSH receptors (FSH-R^−/−). At birth, the number and proliferative index of Sertoli cells were significantly lower in FSH-R^−/− mice than in wild type neonates. Claudin 11 mRNA expression also was significantly reduced in FSH-R^−/− testes at 0 and 8 dpp, whereas the mRNA levels of other Sertoli cell markers (Transferrin and Desert hedgehog) were comparable in FSH-R^−/− and wild type testes. Conversely, AMH mRNA and protein levels were higher at birth, comparable at 6 dpp and then significantly lower in FSH-R^−/− testes at 8–10 dpp in FSH-R^−/− mice than in controls. Although the plasma concentration of LH and the number of Leydig cells were similar in FSH-R^−/− and control (wild type), testosterone concentration and P450c17 mRNA expression were significantly increased in FSH-R^−/− testes at birth. Conversely, at 10 dpp when adult Leydig cells appear, expression of the steroidogenic genes P450scc, P450c17 and StAR was lower in FSH-R^−/− testes than in controls. In conclusion, our results show that 1) like in the rat, signaling via FSH-R controls Sertoli cell development and function during late fetal life in the mouse as well; 2) paracrine factors produced by Sertoli cells are involved in the FSH-R-dependent regulation of the functions of fetal Leydig cells in late fetal life; and 3) the role of FSH-R signaling changes during the prepubertal period.

GATA4 is a critical regulator of gonadectomy-induced adrenocortical tumorigenesis in mice

In response to gonadectomy certain inbred mouse strains develop sex steroidogenic adrenocortical neoplasms. One of the hallmarks of neoplastic transformation is expression of GATA4, a transcription factor normally present in gonadal but not adrenal steroidogenic cells of the adult mouse. To show that GATA4 directly modulates adrenocortical tumorigenesis and is not merely a marker of gonadal-like differentiation in the neoplasms, we studied mice with germline or conditional loss-of-function mutations in the Gata4 gene. Germline Gata4 haploinsufficiency was associated with attenuated tumor growth and reduced expression of sex steroidogenic genes in the adrenal glands of ovariectomized B6D2F1 and B6AF1 mice. At 12 months after ovariectomy, wild-type B6D2F1 mice had biochemical and histological evidence of adrenocortical estrogen production, whereas Gata4(+/-) B6D2F1 mice did not. Germline Gata4 haploinsufficiency exacerbated the secondary phenotype of postovariectomy obesity in B6D2F1 mice, presumably by limiting ectopic estrogen production in the adrenal glands. Amhr2-cre-mediated deletion of floxed Gata4 (Gata4(F)) in nascent adrenocortical neoplasms of ovariectomized B6.129 mice reduced tumor growth and the expression of gonadal-like markers in a Gata4(F) dose-dependent manner. We conclude that GATA4 is a key modifier of gonadectomy-induced adrenocortical neoplasia, postovariectomy obesity, and sex steroidogenic cell differentiation.

Animal models for aberrations of gonadotropin action

During the last two decades a large number of genetically modified mouse lines with altered gonadotropin action have been generated. These mouse lines fall into three categories: the lack-of-function mice, gain-of-function mice, and the mice generated by breeding the abovementioned lines with other disease model lines. The mouse strains lacking gonadotropin action have elucidated the necessity of the pituitary hormones in pubertal development and function of gonads, and revealed the processes from the original genetic defect to the pathological phenotype such as hypo- or hypergonadotropic hypogonadism. Conversely, the strains of the second group depict consequences of chronic gonadotropin action. The lines vary from those expressing constitutively active receptors and those secreting follicle-stimulating hormone (FSH) with slowly increasing amounts to those producing human choriogonadotropin (hCG), amount of which corresponds to 2000-fold luteinizing hormone (LH)/hCG biological activity. Accordingly, the phenotypes diverge from mild anomalies and enhanced fertility to disrupted gametogenesis, but eventually chronic, enhanced and non-pulsatile action of both FSH and LH leads to female and male infertility and/or hyper- and neoplasias in most of the gonadotropin gain-of-function mice. Elevated gonadotropin levels also alter the function of several extra-gonadal tissues either directly or indirectly via increased sex steroid production. These effects include promotion of tumorigenesis in tissues such as the pituitary, mammary and adrenal glands. Finally, the crossbreedings of the current mouse strains with other disease models are likely to uncover the contribution of gonadotropins in novel biological systems, as exemplified by the recent crossbreed of LHCG receptor deficient mice with Alzheimer disease mice.

Transcriptional control of adrenal steroidogenesis: novel connection between Janus kinase (JAK) 2 protein and protein kinase A (PKA) through stabilization of cAMP response element-binding protein (CREB) transcription factor

In the adrenal gland, adrenocorticotropin (ACTH) acting through the cAMP protein kinase (PKA) transduction pathway is the main regulator of genes involved in glucocorticoid synthesis. The prolactin (PRL) receptor is expressed in the adrenal cortex of most mammals, but experimental proof that PRL ensures direct control on glucocorticoid synthesis in rodents remains elusive. To unravel the physiological importance of PRL in adrenocortical functions, we measured steroidogenic capacity of Prlr-deficient mice (Prlr(-/-)) and explored the influence of JAK/STAT signaling, the major PRL transduction pathway, on the steroidogenic activity of adrenocortical cell cultures. We demonstrate that lack of Prlr does not affect basal (nor stress-induced) corticosterone levels in mice. PRL triggers JAK2/STAT5-dependent transcription in adrenal cells, but this does not influence corticosterone release. In contrast, pharmacological or siRNA-mediated inhibition of JAK2 reveals its essential role in both basal and ACTH/cAMP-induced steroidogenesis. We demonstrate that nuclear JAK2 regulates the amount of active transcription factor CREB (cAMP response element-binding protein) through tyrosine phosphorylation and prevention of proteasomal degradation, which in turn leads to transcriptional activation of the rate-limiting steroidogenic Star gene. Hence, we describe a novel link between PKA and JAK2 by which nuclear JAK2 signaling controls adrenal steroidogenesis by increasing the stability of CREB.

Prenatal androgen exposure leads to alterations in gene and protein expression in the ovine fetal ovary

Exposure of a female fetus to increased androgens in utero results in an adult phenotype reminiscent of polycystic ovary syndrome. We investigated whether prenatal androgens could directly alter the structure and function of the fetal ovary. We examined fetal ovarian cell proliferation, germ cell volume, and the expression of steroid receptors and steroidogenic enzymes. In addition, we studied the inhibitors of differentiation (Ids) and the SLIT/Roundabout developmental pathways. Female fetuses were collected from ewes treated with 100 mg testosterone propionate (TP) or vehicle control (C), twice weekly from d 60 to 70 (C = 3, TP = 6) or d 90 (C = 6, TP = 8). Female fetuses were also collected at d 70 after a single injection of TP (20 mg) or vehicle C into the fetal flank at d 60 (C = 4, TP = 8). Prenatal androgenization had no effect on fetal ovarian morphology, cell proliferation, or germ cell volume. However, there was a reduction in the expression of StAR, CYP11A, CYP17, and LHR at d 90 of gestation. There was also an increase in Id1 immunostaining at d 90 and an increase in Id3 immunostaining at d 70. Direct injection of TP into the fetus down-regulated ovarian CYP11A, estrogen receptor α and β mRNA, and ROBO1 and up-regulated CYP19, androgen receptor immunostaining, and Id3 mRNA and protein. Although at d 90 prenatal androgenization does not result in structural changes of the fetal ovary, there are functional changes that may impact on ovarian development. TP has direct actions on the fetal ovary, and these may contribute to the adult ovarian phenotype in the ovine model of polycystic ovary syndrome.

[Hypoplasia adrenal congenita of anencephalic type: two cases with pituitary abnormalities and review of literature]

Hypoplasia adrenal congenita is an extremely uncommon disease of early onset. This condition can be lethal in the absence of treatment. Some forms are due to the congenital adrenal hypoplasia of anencephalic type whose origin is even unknown. Here, we present two cases of congenital adrenal hypoplasia of anencephalic type with pituitary abnormalities. The two male newborns died because adrenal insufficiency in the neonatal period. The adrenal glands were hypoplastic with a histological structure of anencephalic type Immunocytochemical study of the pituitary revealed an absence of the gonadotrophs. No mutation of DAX 1 and SF-1 was found.

Human adrenal LH/hCG receptors and what they could mean for adrenal physiology and pathology

Although the research on the potential regulation of human adrenal cortex by LH and hCG is still in its infancy, the available evidence supports the presence of very low levels of LH/hCG receptors in entire zona reticularis and deeper part of zona fasciculata. The activation of these receptors may lead to an increased secretion of androgens and/or cortisol. The same chronically elevated levels, along with unknown genetic and epigenetic changes, may also lead to the formation of tumors that can secrete all three major classes of adrenal steroid hormones. As shown in murine models, the increased receptor levels often seen in tumors, are probably caused by elevated LH/hCG levels. However, the elevated LH/hCG levels or their receptors alone may not be sufficient for the development of adrenal pathology. Therefore, further studies to advance our current understanding on the pathophysiology of human adrenal hCG/LH receptors are required.

Are gonadotrophins tumorigenic--a critical review of clinical and experimental data

The growth of many gonadal and extragonadal tumors is stimulated by gonadal sex hormones. Because gonadal hormone production is regulated by pituitary gonadotrophins, the latter hormones can be considered as indirect tumor promoters. In addition, there is a growing body of evidence that both gonadal (e.g. ovarian cancer) and extragonadal (e.g. breast, uterus, prostate and adrenal) tumors express gonadotrophin receptors, indicating the possibility of a direct tumorigenic role for FSH and LH. The purpose of this brief review is to present a critical evaluation of the current information, both clinical and experimental, about the direct involvement of gonadotrophins in the induction and growth of gonadal and extragonadal tumors.

Female mice expressing constitutively active mutants of FSH receptor present with a phenotype of premature follicle depletion and estrogen excess

Strong gain-of-function mutations have not been identified in humans in the FSH receptor (FSHR), whereas such mutations are common among many other G protein-coupled receptors. In order to predict consequences of such mutations on humans, we first identified constitutively activated mutants of the mouse (m) Fshr and then expressed them under the human anti-Müllerian hormone promoter in transgenic mice or created knock-in mutation into the mouse genome. We show here that mutations of Asp580 in the mFSHR significantly increase the basal receptor activity. D580H and D580Y mutations of mFSHR bind FSH, but the activity of the former is neither ligand-dependent nor promiscuous towards LH/human choriogonadotropin stimulation. Transgenic expression of mFshr(D580H) in granulosa cells leads to abnormal ovarian structure and function in the form of hemorrhagic cysts, accelerated loss of small follicles, augmented granulosa cell proliferation, increased estradiol biosynthesis, and occasional luteinized unruptured follicles or teratomas. The most affected mFshr(D580H) females are infertile with disturbed estrous cycle and decreased gonadotropin and increased prolactin levels. Increased estradiol and prolactin apparently underlie the enhanced development of the mammary glands, adenomatous pituitary growth, and lipofuscin accumulation in the adrenal gland. The influence of the mFSHR(D580Y) mutation is milder, mainly causing hemorrhagic cysts in transgenic mFSHR(D580Y) and mFSHR(D580Y) -knock-in mice. The results demonstrate that gain-of-function mutations of the FSHR in mice bring about distinct and clear changes in ovarian function, informative in the search of similar mutations in humans.

Inhibin-A antagonizes TGFbeta2 signaling by down-regulating cell surface expression of the TGFbeta coreceptor betaglycan

Inhibin is an atypical member of the TGFbeta family of signaling ligands and is classically understood to function via competitive antagonism of activin ligand binding. Inhibin-null (Inha-/-) mice develop both gonadal and adrenocortical tumors, the latter of which depend upon gonadectomy for initiation. We have previously shown that gonadectomy initiates adrenal tumorigenesis in Inha-/- mice by elevating production of LH, which drives aberrant proliferation and differentiation of subcapsular adrenocortical progenitor cells. In this study, we demonstrate that LH signaling specifically up-regulates expression of TGFbeta2 in the subcapsular region of the adrenal cortex, which coincides with regions of aberrant Smad3 activation in Inha-/- adrenal glands. Consistent with a functional interaction between inhibin and TGFbeta2, we further demonstrate that recombinant inhibin-A antagonizes signaling by TGFbeta2 in cultured adrenocortical cells. The mechanism of this antagonism depends upon the mutual affinity of inhibin-A and TGFbeta2 for the signaling coreceptor betaglycan. Although inhibin-A cannot physically displace TGFbeta2 from its binding sites on betaglycan, binding of inhibin-A to the cell surface causes endocytic internalization of betaglycan, thereby reducing the number of available binding sites for TGFbeta2 on the cell surface. The mechanism by which inhibin-A induces betaglycan internalization is clathrin independent, making it distinct from the mechanism by which TGFbeta ligands themselves induce betaglycan internalization. These data indicate that inhibin can specifically antagonize TGFbeta2 signaling in cellular contexts where surface expression of betaglycan is limiting and provide a novel mechanism for activin-independent phenotypes in Inha-/- mice.

Adrenal hyperplasia and tumours in mice in connection with aberrant pituitary-gonadal function

Gonadectomy induces in certain inbred stains of mice adrenal hyperplasia and tumorigenesis, originating from the putative subcapsular stem/progenitor cell layer. This response is apparently triggered by the elevated post-gonadectomy levels of luteinising hormone (LH), followed by ectopic upregulation of adrenal LH/chorionic gonadotrophin (CG) receptors (Lhcgr). The clear strain dependence of this adrenal response to gonadectomy prompted us to study its genetic basis. Tumorigenic DBA/2J and non-tumorigenic C57BL/6J mice, as well as their F2 and backcrosses, were studied by whole genome linkage analysis. Gonadectomy induced similar upregulation of adrenal Lhcgr in both parental strains and their crosses, irrespective of the tumour status, indicating that ectopic expression of this receptor is not the immediate cause of tumours. Linkage analysis revealed one major significant quantitative trait locus (QTL) for the tumorigenesis on chromosome 8, modulated by epistasis with another QTL on chromosome 18. Hence, post-gonadectomy adrenal tumorigenesis in DBA/2J mice is a dominant trait, not a direct consequence of adrenal Lhcgr expression, and is driven by a complex genetic architecture. A promising candidate gene in the tumorigenesis linkage region is Sfrp1 (secreted frizzled-related protein 1), a tumour suppressor gene, which was down-regulated in the neoplastic tissue. Our findings may have relevance to the human pathogenesis of macronodular adrenal hyperplasia and postmenopausal adrenocortical tumours. A distinctly different adrenal response was observed in TG mice overexpressing LH or CG, or a constitutively activated form of the follicle-stimulating hormone receptor (Fshr). These mice developed perimedullary hyperlasia of foamy multinucleated cells, reminding of macrophages and filled with lipofuscin. Similar response was observed in TG mice overexpressing aromatase (CYP19). The cause of this response is not related to direct LH/CG action, but merely to adrenal response to chronically elevated oestrogen levels. This phenotype is reminiscent of the rare 'black adenomas' of the human adrenal cortex.