Androgens in women are essentially made from DHEA in each peripheral tissue according to intracrinology.

The objective is to review how the cell-specific amounts of intracellular androgens are all made in women from circulating dehydroepiandrosterone (DHEA) in each peripheral tissue, independently from the rest of the body. Following 500 million years of evolution, approximately three dozen cell-specific intracrine enzymes have been engineered in human peripheral tissues whereby the inactive sex steroid precursor DHEA mainly of adrenal origin is transformed into the appropriate minute intracellular amounts of androgens. These intracellular androgens are inactivated in the same cells, with no biologically significant release of active androgens in the circulation. The best estimate is that approximately 50% as much androgens are synthesized in women, compared to men of the same age. The problem with DHEA, however, the exclusive source of androgens in women of all ages, is that DHEA secretion has already decreased by an average of 60% at time of menopause and continues to decrease thereafter. The human-specific and highly sophisticated mechanisms of intracrinology permit each cell to control androgen availability according to its own needs independently from the remaining of the body. Such a mechanism is completely different from classical endocrinology well understood in men where testosterone of testicular origin is transported through the blood and has indiscriminate access to the androgen receptor (AR) in all AR-containing cells of the body. In men, both the endocrine and intracrine mechanisms are in operation while, in women, only the intracrine mechanisms responsible for intracellular formation from DHEA provide androgens.

Science of intracrinology in postmenopausal women.

OBJECTIVE: To illustrate the marked differences between classical endocrinology that distributes hormones to all tissues of the body through the bloodstream and the science of intracrinology, whereby each cell of each peripheral tissue makes a small and appropriate amount of estrogens and androgens from the inactive precursor dehydroepiandrosterone (DHEA), DHEA being mainly of adrenal origin. Because only the inactivated sex steroids are released in the blood, influence in the other tissues is avoided. METHODS: Molecular biology has been used for the identification/characterization of the steroid-forming and steroid-inactivating enzymes, whereas steroids have been measured by mass spectrometry-based assays validated according to the US Food and Drug Administration guidelines. RESULTS: Evolution over 500 million years has engineered the expression of about 30 steroid-forming enzymes specific for each peripheral tissue. These tissue-specific enzymes transform DHEA into the appropriate small amounts of estrogens and androgens for a strictly intracellular and local action. Humans, contrary to species below primates, also possess intracellular steroid-inactivating enzymes, especially glucuronyl transferases and sulfotransferases, which inactivate the estrogens and androgens at their local site of formation, thus preventing the release of a biologically significant amount of estradiol (E2) and testosterone in the circulation. Since DHEA becomes the unique source of sex steroids after menopause, serum E2 and testosterone are thus maintained at low biologically inactive concentrations with no activity outside the cells of origin. DHEA secretion, unfortunately, starts decreasing at about the age of 30 at various rates in different women. Moreover, there is no feedback mechanism to increase DHEA secretion when the concentration of serum DHEA decreases. Considering this mechanism is unique to the human, it seems logical to replace DHEA locally in women suffering from vulvovaginal atrophy (genitourinary syndrome of menopause). The clinical data obtained using a small dose of intravaginal DHEA (prasterone) confirm the mechanisms of intracrinology mentioned above which avoid biologically significant changes in serum E2 and testosterone. CONCLUSIONS: The symptoms and signs of vulvovaginal atrophy (genitourinary syndrome of menopause) can be successfully treated by the intravaginal administration of DHEA without safety concerns. This strategy exclusively replaces in the vagina the missing cell-specific intracellular estrogens and androgens. This approach avoids systemic exposure and the potential risks of estrogen exposure for the tissues other than the vagina.

Is vulvovaginal atrophy due to a lack of both estrogens and androgens?

OBJECTIVE: The aim of this study was to review the preclinical data showing the role of both estrogens and androgens in the physiology of the vagina, and, most likely, in vulvovaginal atrophy of menopause. METHODS: Mass spectrometry-based assays (validated according to the FDA guidelines) for the measurement of sex steroids, their precursors, and metabolites were used. In addition to fixation of the vagina for morphological examination, histomorphometry, immunocytochemistry, immunofluorescence, and quantitative reverse transcription polymerase chain reaction were performed. RESULTS: The vaginal epithelium of the animals receiving dehydroepiandrosterone (DHEA) was made of large multilayered columnar mucous cells showing distended cytoplasmic vacuoles representative of an androgenic effect. DHEA also stimulates collagen fiber compactness of the lamina propria (second layer)-an effect essentially due to an androgenic effect, whereas stimulation by DHEA of the muscularis in the third vaginal layer is approximately 70% due to the androgenic conversion of DHEA. Stimulation of the surface area of the nerve endings, on the contrary, is exclusively androgenic. Vaginal weight stimulation by DHEA is about 50% androgenic and 50% estrogenic. CONCLUSIONS: Practically all studies on the influence of steroid hormones in the vagina have focused on luminal epithelial cells. Since all estrogens and androgens in postmenopausal women are made intracellularly and derive from the conversion of circulating DHEA, it is of interest to observe from these preclinical data that DHEA exerts both estrogenic and androgenic activity in the three layers of the vagina, the stimulatory effect on nerve density being 100% androgenic. Taking vaginal weight as a global parameter, the stimulatory effect of DHEA in the rat vagina is about equally estrogenic and androgenic, thus illustrating the importance of androgens in vaginal morphology and function, and the likely importance of androgens in vulvovaginal atrophy of menopause.

Increased Hypothalamic Levels of Endozepines, Endogenous Ligands of Benzodiazepine Receptors, in a Rat Model of Sepsis.

BACKGROUND: The mechanisms involved in septic anorexia are mainly related to the secretion of inflammatory cytokines. The term endozepines designates a family of neuropeptides, including the octadecaneuropeptide (ODN), originally isolated as endogenous ligands of benzodiazepine receptors. Previous data showed that ODN, produced and released by astrocytes, is a potent anorexigenic peptide. We have studied the effect of sepsis by means of a model of cecal ligation and puncture (CLP) on the hypothalamic expression of endozepines (DBI mRNA and protein levels), as well as on the level of neuropeptides controlling energy homeostasis mRNAs: pro-opiomelanocortin, neuropeptide Y, and corticotropin-releasing hormone. In addition, we have investigated the effects of two inflammatory cytokines, TNF-α and IL-1ß, on DBI mRNA levels in cultured rat astrocytes. METHODS: Studies were performed on Sprague-Dawley male rats and on cultures of rat cortical astrocytes. Sepsis was induced using the CLP method. Sham-operated control animals underwent the same procedure, but the cecum was neither ligated nor incised. RESULTS: Sepsis caused by CLP evoked an increase of DBI mRNA levels in ependymal cells bordering the third ventricle and in tanycytes of the median eminence. CLP-induced sepsis was also associated with stimulated ODN-like immunoreactivity (ODN-LI) in the hypothalamus. In addition, TNF-α, but not IL-1ß, induced a dose-dependent increase in DBI mRNA in cultured rat astrocytes. An increase in the mRNA encoding the precursor of the anorexigenic peptide α-melanocyte stimulating hormone, the pro-opiomelanocortin, and the corticotropin-releasing hormone was observed in the hypothalamus. CONCLUSION: These results suggest that during sepsis, hypothalamic mRNA encoding endozepines, anorexigenic peptide as well as stress hormone could play a role in the anorexia/cachexia associated with inflammation due to sepsis and we suggest that this hypothalamic mRNA expression could involve TNF-α.

Review of Canadian species of the genus Mocyta Mulsant & Rey (Coleoptera, Staphylinidae, Aleocharinae), with the description of a new species and a new synonymy.

Six species of the genus Mocyta Mulsant & Rey are reported from Canada: Mocytaamblystegii (Brundin), Mocytabreviuscula (Mäklin), Mocytadiscreta (Casey), Mocytafungi (Gravenhorst), Mocytaluteola (Erichson), and Mocytasphagnorum Klimaszewski & Webster, sp. n. New provincial and state records include: Mocytabreviuscula - Saskatchewan and Oregon; Mocytadiscreta - Quebec, Ontario and Saskatchewan; Mocytaluteola - New Brunswick, Quebec, Ontario, Massachusetts and Minnesota; and Mocytafungi - Saskatchewan. Mocytasphagnorum is described from eastern Canada from specimens captured in Newfoundland, New Brunswick, Quebec and Ontario. Mocytanegligens Mulsant and Rey, a native European species suspected of occurring in Canada, is excluded from the Nearctic fauna based on comparison of European types with similarly coloured Canadian specimens, which are now identified as Mocytaluteola. The European species, Mocytagilvicollis (Scheerpeltz), is synonymized with another European nominal species, Mocytanegligens, based on examination of type material of the two species. Lectotypes are designated for Eurypronotadiscreta Casey, Athetagilvicollis Scheerpeltz, Homalotaluteola Erichson, Colpodotanegligens Mulsant and Rey, Acrotonaprudens Casey and Dolosotaredundans Casey. The latter species is here synonymized with Mocytaluteola. A review of the six Nearctic species is provided, including keys to species and closely related genera, colour habitus images, images of genitalia, biological information and maps of their distributions in Canada.

Expression of the estrogen receptors and steroidogenic enzymes involved in estradiol formation in the monkey vagina.

OBJECTIVE: Estrogens are well recognized to have beneficial effects on vulvovaginal atrophy because of menopause. The distribution of estrogen receptors and enzymes responsible for estradiol (E2) formation within the vagina may provide insight into how dehydroepiandrosterone, a precursor of both estrogens and androgens, improves vulvovaginal atrophy. STUDY DESIGN: The purpose of the study was to determine where the steroidogenic enzymes responsible for E2 formation as well as estrogen receptors are localized in vaginal specimens collected from cynomolgus monkeys (Macaca fascicularis), the closest model to the human. HSD3B1, HSD17B1, HSD17B5, HSD17B12, aromatase (CYP19A1), estrogen receptor (ER)-α, and ER-ß were measured or localized by quantitative real-time polymerase chain reaction, immunohistochemistry, and immunofluorescence. Estrogens were quantified by liquid chromatography/tandem mass spectrometry. RESULTS: All steroidogenic enzymes and estrogen receptors are localized mainly in the superficial layer of the stratified squamous epithelium, blood vessel walls, and muscle fibers of the vagina. Immunolabeling of HSD17B5 and HSD17B12 shows that these enzymes are uniformly distributed from the basal membrane to the superficial keratinized cells, whereas HSD3B1 and aromatase are particularly localized in the outer (external) portion of the epithelial layer. ER-α and ER-ß are also distributed within the vaginal epithelium, with expression especially elevated at the basal membrane level. CONCLUSION: The enzymes responsible for E2 formation as well as ERs are expressed mainly in the superficial layer of the stratified epithelium as well as the muscle layer of the vagina. The present data provide morphologic and biochemical support for the role of local dehydroepiandrosterone transformation into estrogens in regulating epithelial cell maturation, pH, fluid secretion, smooth muscle activity, and blood flow regulation in the primate vagina.

Localization of the androgen-synthesizing enzymes, androgen receptor, and sex steroids in the vagina: possible implications for the treatment of postmenopausal sexual dysfunction.

INTRODUCTION: To better understand the mechanisms underlying the beneficial effects of the intravaginal administration of dehydroepiandrosterone (DHEA) observed in postmenopausal women on sexual dysfunction. AIMS: To identify the distribution of the androgen-synthesizing enzymes as well as androgen receptor (AR) and measure steroid levels in the monkey vagina. METHODS: The cynomolgus monkey (Macaca fascicularis), the closest model to the human, has been used to measure the expression levels of steroidogenic enzymes and androgen receptor by quantitative reverse transcription polymerase chain reaction (n=4), confirmed by immunohistochemistry, and immunofluorescence (n=3). DHEA and its androgenic metabolites were quantified by LC-MS/MS (n=4). MAIN OUTCOME MEASURES: The presence of SRD5A1, SRD5A2, HSD17B3, AR as well as nerve fibers (PGP 9.5) was investigated, and steroid levels were measured. RESULTS: AR is widely distributed within the vaginal epithelium and also in the lamina propria with a lower expression in the muscularis layer and blood vessel walls. Androgen-forming enzymes, on the other hand, are expressed in the vaginal stratified squamous epithelium at a relatively high level where they are uniformly distributed from the basal membrane up to the superficial keratinized cells. The enzymes are at a lower level in blood vessel walls and zona muscularis where nerve fibers are localized. DHEA and its androgen metabolites are present at biologically significant concentrations in the monkey vagina. CONCLUSION: The enzymes responsible for androgen formation as well as AR are at the highest level in the superficial layer of the stratified epithelium and muscularis layers of the vagina. These data provide a potential explanation for the described role of androgens in regulating vaginal lubrication, smooth muscle activity, blood flow, and the neuronal activity potentially involved in the correction of sexual dysfunction.

Androgenic action of dehydroepiandrosterone (DHEA) on nerve density in the ovariectomized rat vagina.

INTRODUCTION: We have recently reported that dehydroepiandrosterone (DHEA) increases the density of nerve fibers in the ovariectomized (OVX) rat vagina. AIM: To better define the mechanism of action of DHEA, we have examined the effect of DHEA, conjugated estrogens (premarin) and the potent blocker of estrogen action acolbifene on the innervation in the lamina propria in the OVX rat vagina. METHODS: Female Sprague-Dawley rats (10-12 weeks old) were used. Innervation of the vagina was examined 9 months after OVX and was compared to that of OVX animals treated daily with DHEA (80 mg/kg) by topical application on the skin, premarin (0.5 mg/kg) orally as well as acolbifene (2.5 mg/kg) orally administrated alone or in combination with DHEA or premarin. MAIN OUTCOME MEASURES: Four histological sections from each vagina (5 animals/group) were immunostained using antibodies to the panneuronal marker protein gene product 9.5 (PGP 9.5). The areas were measured by stereological analysis. RESULTS: OVX reduced the area of the lamina propria to 44% of the intact value, an effect which was reversed to 69% and 84% of the intact value by DHEA and premarin, respectively, at the doses used. When acolbifene was used, no inhibition of the stimulatory effect of DHEA was observed, while the action of premarin was completely blocked. Evaluation of the PGP 9.5 fiber density revealed that DHEA treatment increased the density of fibers by 60% compared to OVX animals, while a further 27% increase was observed when acolbifene was combined with DHEA. Premarin, on the other hand, had no effect on the density of PGP 9.5 fibers. CONCLUSIONS: Considering that the antiestrogen acolbifene had no inhibitory effect on the effect of DHEA in rat vagina while blocking the stimulatory effect of premarin, the present data indicate that DHEA exerts its stimulatory effect on the fiber density through an androgenic action.

Gonadotropin-releasing hormone stimulates the biosynthesis of pregnenolone sulfate and dehydroepiandrosterone sulfate in the hypothalamus.

The sulfated neurosteroids pregnenolone sulfate (Δ(5)PS) and dehydroepiandrosterone sulfate (DHEAS) are known to play a role in the control of reproductive behavior. In the frog Pelophylax ridibundus, the enzyme hydroxysteroid sulfotransferase (HST), responsible for the biosynthesis of Δ(5)PS and DHEAS, is expressed in the magnocellular nucleus and the anterior preoptic area, two hypothalamic regions that are richly innervated by GnRH1-containing fibers. This observation suggests that GnRH1 may regulate the formation of sulfated neurosteroids to control sexual activity. Double labeling of frog brain slices with HST and GnRH1 antibodies revealed that GnRH1-immunoreactive fibers are located in close vicinity of HST-positive neurons. The cDNAs encoding 3 GnRH receptors (designated riGnRHR-1, -2, and -3) were cloned from the frog brain. RT-PCR analyses revealed that riGnRHR-1 is strongly expressed in the hypothalamus and the pituitary whereas riGnRHR-2 and -3 are primarily expressed in the brain. In situ hybridization histochemistry indicated that GnRHR-1 and GnRHR-3 mRNAs are particularly abundant in preoptic area and magnocellular nucleus whereas the concentration of GnRHR-2 mRNA in these 2 nuclei is much lower. Pulse-chase experiments using tritiated Δ(5)P and DHEA as steroid precursors, and 3'-phosphoadenosine 5'-phosphosulfate as a sulfonate moiety donor, showed that GnRH1 stimulates, in a dose-dependent manner, the biosynthesis of Δ(5)PS and DHEAS in frog diencephalic explants. Because Δ(5)PS and DHEAS, like GnRH, stimulate sexual activity, our data strongly suggest that some of the behavioral effects of GnRH could be mediated via the modulation of sulfated neurosteroid production.

Gliotransmission and brain glucose sensing: critical role of endozepines.

Hypothalamic glucose sensing is involved in the control of feeding behavior and peripheral glucose homeostasis, and glial cells are suggested to play an important role in this process. Diazepam-binding inhibitor (DBI) and its processing product the octadecaneuropeptide (ODN), collectively named endozepines, are secreted by astroglia, and ODN is a potent anorexigenic factor. Therefore, we investigated the involvement of endozepines in brain glucose sensing. First, we showed that intracerebroventricular administration of glucose in rats increases DBI expression in hypothalamic glial-like tanycytes. We then demonstrated that glucose stimulates endozepine secretion from hypothalamic explants. Feeding experiments indicate that the anorexigenic effect of central administration of glucose was blunted by coinjection of an ODN antagonist. Conversely, the hyperphagic response elicited by central glucoprivation was suppressed by an ODN agonist. The anorexigenic effects of centrally injected glucose or ODN agonist were suppressed by blockade of the melanocortin-3/4 receptors, suggesting that glucose sensing involves endozepinergic control of the melanocortin pathway. Finally, we found that brain endozepines modulate blood glucose levels, suggesting their involvement in a feedback loop controlling whole-body glucose homeostasis. Collectively, these data indicate that endozepines are a critical relay in brain glucose sensing and potentially new targets in treatment of metabolic disorders.

Effects of ovariectomy and dehydroepiandrosterone (DHEA) on vaginal wall thickness and innervation.

INTRODUCTION: One mechanism by which low sexual steroid activity observed after menopause could cause sexual dysfunction is by deficient vaginal innervation. Recently, it has been shown that intravaginal administration of dehydroepiandrosterone (DHEA) could produce beneficial effects on sexual dysfunction in postmenopausal women. AIM: The goal of this study was to determine if DHEA could modify innervation in the rat vagina. MAIN OUTCOME MEASURES: The area occupied by the nerve fibers immunoreactive for protein gene product 9.5 (PGP 9.5), a panneuronal marker or tyrosine hydroxylase (TH), a sympathetic nerve fiber marker, in the lamina propria and muscular layers, respectively, as well as the total area of each of these 2 layers were measured by stereological analysis. METHODS: The innervation of the rat vagina was examined 9 months after ovariectomy (OVX) compared to intact animals and treatment of OVX animals with DHEA (80 mg/kg). Four sections from each vagina (5 animals/groups) were immunostained. RESULTS: In OVX animals, the lamina propria area was decreased to 44%, an effect which was reversed by DHEA to 69% of the intact value. OVX also caused a 59% decrease in the area of PGP 9.5 fibers, an effect which was prevented by DHEA, thus showing a 68% stimulatory effect of DHEA on the density of PGP 9.5 fibers in the lamina propria compared to OVX animals. Following OVX, the muscular layer area was decreased by 61%. DHEA treatment induced 118% and 71% increases in TH fiber area compared to OVX and intact animals, respectively. The density of TH fibers was 182% increased over intact controls by DHEA treatment of OVX animals. CONCLUSIONS: The relatively potent stimulatory effect of DHEA on intravaginal nerve fiber density provides a possible explanation for the beneficial effects of intravaginal DHEA on sexual dysfunction observed in postmenopausal women.

Regulation of neurosteroid biosynthesis by neurotransmitters and neuropeptides.

The enzymatic pathways leading to the synthesis of bioactive steroids in the brain are now almost completely elucidated in various groups of vertebrates and, during the last decade, the neuronal mechanisms involved in the regulation of neurosteroid production have received increasing attention. This report reviews the current knowledge concerning the effects of neurotransmitters, peptide hormones, and neuropeptides on the biosynthesis of neurosteroids. Anatomical studies have been carried out to visualize the neurotransmitter- or neuropeptide-containing fibers contacting steroid-synthesizing neurons as well as the neurotransmitter, peptide hormones, or neuropeptide receptors expressed in these neurons. Biochemical experiments have been conducted to investigate the effects of neurotransmitters, peptide hormones, or neuropeptides on neurosteroid biosynthesis, and to characterize the type of receptors involved. Thus, it has been found that glutamate, acting through kainate and/or AMPA receptors, rapidly inactivates P450arom, and that melatonin produced by the pineal gland and eye inhibits the biosynthesis of 7α-hydroxypregnenolone (7α-OH-Δ(5)P), while prolactin produced by the adenohypophysis enhances the formation of 7α-OH-Δ(5)P. It has also been demonstrated that the biosynthesis of neurosteroids is inhibited by GABA, acting through GABA(A) receptors, and neuropeptide Y, acting through Y1 receptors. In contrast, it has been shown that the octadecaneuropetide ODN, acting through central-type benzodiazepine receptors, the triakontatetraneuropeptide TTN, acting though peripheral-type benzodiazepine receptors, and vasotocin, acting through V1a-like receptors, stimulate the production of neurosteroids. Since neurosteroids are implicated in the control of various neurophysiological and behavioral processes, these data suggest that some of the neurophysiological effects exerted by neurotransmitters and neuropeptides may be mediated via the regulation of neurosteroid production.

Expression of 11ß-hydroxysteroid dehydrogenase type 1 in breast cancer and adjacent non-malignant tissue. An immunocytochemical study.

Intratumoral biosynthesis of hormone steroids is thought to play a role in the pathogenesis and development of human breast cancer. There is evidence that glucocorticoids may inhibit the development and progression of breast cancer. 11ß-hydroxysteroid dehydrogenase (11ß-HSD) type 1 is the enzyme which converts inactive cortisone to active cortisol. In order to study the expression of 11ß-HSD type 1 in breast cancer and non-cancerous breast tissue, we have developed specific antibodies to 11ß-HSD type 1 and proceeded to localization of the enzyme in 84 specimens of breast carcinoma and adjacent non-malignant tissues by immnohistochemistry. The results were correlated with the expression of androgen receptor, estrogen receptor, progesterone receptor, glucocorticoid receptor and CDC47, a cell division marker, as well as the tumor stage, tumor size, nodal status and menopausal status. The expression of 11ß-HSD type 1 in 64% of breast cancer specimens appeared significantly lower than that observed in normal adjacent tissues (97% of cases being positive). There was no significant correlation between 11ß-HSD type 1 expression and the clinicopathological parameters studied. The decrease in 11ß-HSD type 1 expression in breast cancer as compared to that observed in the adjacent normal tissues may play a role in the development and/or progression of the cancer by modifying the intratumoral levels of glucocorticoids.

Compartmentalized CDK2 is connected with SHP-1 and ß-catenin and regulates insulin internalization.

The cyclin-dependant kinase Cdk2 is compartmentalized in endosomes but its role is poorly understood. Here we show that Cdk2 present in hepatic endosome fractions is strictly located in a Triton X-100-resistant environment. The endosomal Cdk2 was found to be associated with the protein tyrosine phosphatase SHP-1, a regulator of insulin clearance, and the actin anchor ß-catenin, a known substrate for both Cdk2 and SHP-1. In the plasma membranes and endosome fractions, ß-catenin is associated with CEACAM1, also known as regulator of insulin clearance. We show that ß-catenin, not CEACAM1, is a substrate for Cdk2. Partial down-modulation of Cdk2 in HEK293 cells increased the rate of insulin internalization. These findings reveal that Cdk2 functions, at least in part, via a Cdk2/SHP-1/ß-catenin/CEACAM1 axis, and show for the first time that Cdk2 has the capacity to regulate insulin internalization.