Other conceivable renditions of some of the oxidative processes used in the biosynthesis of steroid hormones

The generally accepted version (GAV) of the chemical processes by which the steroid hormones are biosynthesized cannot be considered to be an inerrant description of in vivo processes. Customarily this version is derived by piecing together the results obtained from several independent artificial in vitro incubation experiments. Extrapolation of such results from in vitro to in vivo requires untested assumptions which introduce varying degrees of uncertainty. In vitro incubation experiments reveal only what is possible; not what actually prevails in situ. Presented here are hypothetical alternative renditions of some of the oxidative processes involved in steroidogenesis. These versions suggest that some cytochrome P-450's catalyze the introduction of both oxygen atoms of dioxygen into an appropriate sterol precursor. The products are conceived as oxygen free radicals (peroxy or 1,2-cyclic peroxy) which serve as the "reactive intermediates" (the precursors) for the hormones. The true intermediates are not stable, isolable, hydroxylated compounds as they are customarily portrayed in the GAV. Central to these new renditions is the hypothesis that the appropriate P-450 introduces dioxygen into the precursor yielding either: A, a 20 peroxy sterol species or B, a species oxygenated at both C-17 and C-20 or C, a species oxygenated at both C-20 and C-21. In this hypothesis, A would serve as the precursor for progesterone, B, for the C19-androgens and C18-estrogens and C, for the mineralocorticoids (corticosterone and aldosterone) and the glucocorticoid (cortisol). How this version of steroidogenesis can be used to understand the etiologies of various genetically derived enzyme deficiency diseases of the adrenal and ovaries will be discussed. If as proposed here, the various polyfunctional cytochromes (P-450(scc), P-450(c17,) P-45011B1 (P-450(cortisol)), P-45011B2 (P-450(aldo)), etc.) catalyze conversions that are different from simple hydroxylations, the labels usually given these deficiency diseases may not be appropriate. More importantly, these new conceptions may clarify the etiology of some of the characteristic symptoms of these diseases that are not now adequately explained by the GAV.

Cytokines and hormones in the regulation of hypoxia inducible factor-1alpha (HIF-1alpha)

Hypoxia inducible factor-1 (HIF-1) is a central component of the oxygen sensing system that coordinates cellular responses to conditions of decreased oxygen availability. The hypoxia inducible transcription factor HIF-1 is a heterodimer composed of the helix-loop-helix-Per-Arnt-Sim (bHLH-PAS) proteins HIF-1alpha and the aryl hydrocarbon nuclear translocator (ARNT) also known as HIF-1beta. Transactivation of HIF-1 transmits a hypoxic signal into patho-physiological responses such as angiogenesis, erythropoiesis, vasomotor control, an altered energy metabolism, as well as cell survival decisions by regulating a staidly growing number of target genes. Among recent advances are the discoveries that cytokines and growth factors make use of the 'hypoxic signaling system' under normoxia. Here we summarize current knowledge and existing concepts that help to understand how cytokines and hormones affect protein accumulation of HIF-1alpha and discuss potential implications of activating HIF-1 under normoxia. Considering the fundamental role of cytokines during inflammation may predict a role of HIF-1alpha in coordinating cellular responses to pathogens and point to the connection of cancer and inflammation. Moreover, we will address potential feed-back mechanisms showing an impact of HIF-1 on cytokine production. These considerations suggest an intimate signaling cross-talk between cytokines and the HIF-1 system.

Laparoscopic adrenalectomy for functioning and non-functioning adrenal tumors: analysis of surgical aspects based on histological types

BACKGROUND

The aim of this study was to evaluate whether hormonal functions of the tumor influence the operative results of laparoscopic adrenalectomy, and to analyse the clinical outcomes in patients with various hormonally active adrenal tumors.

METHODS

Clinical and pathological records of 68 patients were reviewed. The average age of patients was 40 years (range 20-75); 39 were women and 29 men. For the comparison, patients were divided into the non-functioning tumor group (n = 22) and the functioning tumor group (n = 46).

RESULTS

All laparoscopic adrenalectomies were finished successfully, and no open surgery was necessary. The median operative time and blood loss in the two groups were similar; however, in subgroup analysis, operative time for pheochromocytoma was significantly longer than that for non-functioning tumor (P = 0.044). No difference was noted in intra- and postoperative data between the groups. Of the 22 patients with aldosteronoma, 18 (81.8%) became normotensive and no longer required postoperative blood pressure medications. Adrenalectomy led to an overall reduction in the median number of antihypertensive medications (P < 0.001). All patients with Cushing adenoma had resolution or improvement of the signs and symptoms during follow-up periods. There was no evidence of biochemical or clinical recurrence in any patient with pheochromocytoma.

CONCLUSION

The results of this retrospective review document that laparoscopic adrenalectomy is a safe and effective treatment for functioning as well as non-functioning adrenal tumors, although endocrinologic features may play a significant role.

Hormone-induced protection against mammary tumorigenesis is conserved in multiple rat strains and identifies a core gene expression signature induced by pregnancy

Women who have their first child early in life have a substantially lower lifetime risk of breast cancer. The mechanism for this is unknown. Similar to humans, rats exhibit parity-induced protection against mammary tumorigenesis. To explore the basis for this phenomenon, we identified persistent pregnancy-induced changes in mammary gene expression that are tightly associated with protection against tumorigenesis in multiple inbred rat strains. Four inbred rat strains that exhibit marked differences in their intrinsic susceptibilities to carcinogen-induced mammary tumorigenesis were each shown to display significant protection against methylnitrosourea-induced mammary tumorigenesis following treatment with pregnancy levels of estradiol and progesterone. Microarray expression profiling of parous and nulliparous mammary tissue from these four strains yielded a common 70-gene signature. Examination of the genes constituting this signature implicated alterations in transforming growth factor-beta signaling, the extracellular matrix, amphiregulin expression, and the growth hormone/insulin-like growth factor I axis in pregnancy-induced alterations in breast cancer risk. Notably, related molecular changes have been associated with decreased mammographic density, which itself is strongly associated with decreased breast cancer risk. Our findings show that hormone-induced protection against mammary tumorigenesis is widely conserved among divergent rat strains and define a gene expression signature that is tightly correlated with reduced mammary tumor susceptibility as a consequence of a normal developmental event. Given the conservation of this signature, these pathways may contribute to pregnancy-induced protection against breast cancer.

Ovarian steroids: the good, the bad, and the signals that raise them

Ovarian steroid production and subsequent local steroid-mediated signaling are critical for normal ovarian processes, including follicle growth, oocyte maturation, and ovulation. In contrast, elevated steroidogenesis and/or increased steroid signaling in the ovary can lead to profound ovarian pathology, such as polycystic ovarian syndrome, the leading cause of infertility in reproductive age women. Through the use of several in vitro and animal models, great strides have been made toward characterizing the mechanisms regulating local steroid production and action in the ovary. Examples of this progress include insights into luteinizing hormone (LH)- and growth factor-mediated signaling, steroidogenic acute regulatory protein (StAR) activation, and both genomic and nongenomic steroid-mediated signaling in somatic and germ cells, respectively. The following review will address these advances, focusing on how this rapidly expanding knowledge base can be used to better understand female reproduction, and to further improve treatments for common diseases of infertility.

A single chondroitin 6-sulfate oligosaccharide unit at Ser-2730 of human thyroglobulin enhances hormone formation and limits proteolytic accessibility at the carboxyl terminus. Potential insights into thyroid homeostasis and autoimmunity

We localized the site of type D (chondroitin 6-sulfate) oligosaccharide unit addition to human thyroglobulin (hTg). hTg was chromatographically separated into chondroitin 6-sulfate-containing (hTg-CS) and chondroitin 6-sulfate-devoid (hTg-CS0) molecules on the basis of their D-glucuronic acid content. In an ample number of hTg preparations, the fraction of hTg-CS in total hTg ranged from 32.0 to 71.6%. By exploiting the electrophoretic mobility shift and metachromasia conferred by chondroitin 6-sulfate upon the products of limited proteolysis of hTg, chondroitin 6-sulfate was first restricted to a carboxyl-terminal region, starting at residue 2514. A single chondroitin 6-sulfate-containing nonapeptide was isolated in pure form from the products of digestion of hTg with endoproteinase Glu-C, and its sequence was determined as LTAGXGLRE (residues 2726-2734, X being Ser2730 linked to the oligosaccharide chain). In an in vitro assay of enzymatic iodination, hTg-CS produced higher yields of 3,5,5 '-triiodothyronine (T3) (171%) and 3,5,3',5'-tetraiodothyronine (T4) (134%) than hTg-CS0. Unfractionated hTg behaved as hTg-CS. Thus, chondroitin 6-sulfate addition to a subset of hTg molecules enhanced the overall level of T4 and, in particular, T3 formation. Furthermore, the chondroitin 6-sulfate oligosaccharide unit of hTg-CS protected peptide bond Lys2714-Gly2715 from proteolysis, during the limited digestion of hTg-CS with trypsin. These findings provide insights into the molecular mechanism of regulation of the hormonogenic efficiency and of the T4/T3 ratio in hTg. The potential implications in the ability of hTg to function as an autoantigen and into the pathogenesis of thyroidal and extra-thyroidal manifestations of autoimmune thyroid disease are discussed.

Steroidogenesis in zebrafish and mouse models

Steroid hormones regulate physiological homeostasis for salt, sugar, and sex differentiation. All steroids are synthesized from a common precursor, cholesterol, in a step that converts cholesterol to pregnenolone. The enzyme carrying out this first conversion step is CYP11A1. To further investigate the importance of steroid biosynthesis, animal models with defects in the Cyp11a1 gene are used. Mice with targeted disruption of the Cyp11a1 gene produce no steroids with severe adrenal defects. These mice survive during embryogenesis, but die after birth. Zebrafish with a block in cyp11a1 gene function has an earlier defect, presumably because it lacks adequate maternal steroid supply. When cyp11a1 activity was compensated by the injection of antisense morpholino oligos, the embryos have shortened axis and a defect of epibolic cell movement during early embryogenesis. The discovery of steroid function in cell movement is novel, and should provide new insights into our understanding of diverse functions of steroids.

The immunomodulatory effects of hypertonic saline resuscitation in patients sustaining traumatic hemorrhagic shock: a randomized, controlled, double-blinded trial

OBJECTIVE

To investigate the potential immunologic and anti-inflammatory effects of hypertonic saline plus dextran (HSD) in hemorrhagic trauma patients.

BACKGROUND

Unbalanced inflammation triggered by shock has been linked to multiorgan dysfunction (MOD) and death. In animal and cellular models, HSD alters the inflammatory response to shock, attenuating MOD and improving outcome. It remains untested whether HSD has similar effects in humans.

METHODS

A single 250-mL dose of either HSD (7.5% NaCl, 6% dextran-70) or placebo (0.9% NaCl) was administered to adult blunt trauma patients in hemorrhagic shock. The primary outcome was to measure changes in immune/inflammatory markers, including neutrophil activation, monocyte subset redistribution, cytokine production, and neuroendocrine changes. Patient demographics, fluid requirements, organ dysfunction, infection, and death were recorded.

RESULTS

A total of 27 patients were enrolled (13 HSD) with no significant differences in clinical measurements. Hyperosmolarity was modest and transient, whereas the immunologic/anti-inflammatory effects persisted for 24 hours. HSD blunted neutrophil activation by abolishing shock-induced CD11b up-regulation and causing CD62L shedding. HSD altered the shock-induced monocyte redistribution pattern by reducing the drop in "classic" CD14 and the expansion of the "pro-inflammatory" CD14CD16 subsets. In parallel, HSD significantly reduced pro-inflammatory tumor necrosis factor (TNF)-alpha production while increasing anti-inflammatory IL-1ra and IL-10. HSD prevented shock-induced norepinephrine surge with no effect on adrenal steroids.

CONCLUSIONS

This first human trial evaluating the immunologic/anti-inflammatory effects of hypertonic resuscitation in trauma patients demonstrates that HSD promotes a more balanced inflammatory response to hemorrhagic shock, raising the possibility that similar to experimental models, HSD might also attenuate post-trauma MOD.

In vitro steroid production by adrenals and kidney-gonads from embryonic southern snow skinks (Niveoscincus microlepidotus): implications for the control of the timing of parturition?

In some mammalian species, hormones produced by the embryo(s) at the completion of development are involved in the cascade of events that result in parturition. Our overall aim was to determine whether a similar mechanism exists in viviparous reptiles. The alpine skink Niveoscincus microlepidotus provides a useful model for studies of gestation and parturition in viviparous reptiles as the completion of embryonic development and parturition are temporally separated; ovulation occurs in spring, embryonic development is completed by autumn, but parturition does not occur until the following spring. In this study, we determined how in vitro steroid hormone production by embryonic adrenals (progesterone, corticosterone, and testosterone) and mesonephric kidney-gonads (oestradiol and testosterone) varied during the later stages of gestation. We hypothesised that embryonic adrenals and kidney-gonads were capable of producing steroid hormones in vitro, and that the pattern of production would change as parturition approached, would be influenced by temperature, and would increase in the presence of corticotropin (ACTH) or pregnenolone, respectively. Embryonic adrenals and kidney-gonads were incubated with or without ACTH or the steroid precursor pregnenolone, respectively. Tissues were incubated for 3 h at either 16 or 24 degrees C (preferred body temperature of pregnant N. microlepidotus). Incubation medium was analysed for steroid hormones using radioimmunoassay. Low levels of progesterone were produced in vitro during the later stages of gestation when embryonic adrenals were incubated with ACTH. In vitro corticosterone production by embryonic adrenals also occurred, with greater production occurring when tissues were incubated at 24 degrees C. Testosterone was produced in vitro by both adrenals and kidney-gonads in March (late autumn when embryonic development was complete, but prior to parturition the following spring), with greater production at 16 degrees C. This peak in testosterone production coincided with differentiation and continuing growth of the hemipenes. Low levels of oestradiol were produced in vitro by embryonic kidney-gonads in March. These results provide some support for the hypothesis that corticosterone production by the embryonic adrenal may have a role in determining the timing of parturition in a viviparous reptilian species. Further research is needed to differentiate the activity of various tissues and steroid hormones in control of embryonic development, sexual differentiation, and the potential regulation of gestation and parturition in N. microlepidotus and other viviparous reptiles.

The boar testis: the most versatile steroid producing organ known

A review of the remarkable production of steroids by the testes of the boar is presented, with the principal aims of highlighting the achievements of the Leydig cells and, at the same time, pointing to the considerable deficiencies in our understanding of its biological relevance. The onset of gonadal steroidogenesis at an early stage of sex differentiation and the pattern of pre- and postnatal secretion of steroids are outlined. This is followed by a list of steroids identified in extracts of the boar testis, with emphasis on those that can reasonably be assumed to be secretory products of the Leydig cells. For example, the high concentrations of 16-unsaturated C19 and sulphoconjugated compounds are noted. Next, an impressive list of steroids found in venous blood from the boar testis is given; among them are the 16-unsaturated steroids, the oestrogens and dehydroepiandrosterone, all mainly in the form of sulphates. However, the list also includes some less likely members, such as 11-OH and 19-OH androgens as well as 5alpha-reduced steroids. Lastly, the high concentrations of steroids reported in testicular lymph, especially sulphates, are mentioned. Although roles for testosterone are uncontested, and even for the pheromone-like C19 steroids, there is little that can be said with assurance about the other compounds listed. Some speculations are made on their possible contributions to the reproductive physiology of the boar. This is done to provoke interest and, perhaps, even action towards reaching a more complete understanding of the biological significance of the steroidogenic powers of porcine Leydig cells.

Embryonic gene expression and pro-protein processing of proSAAS during rodent development

In vitro assays have demonstrated that peptides derived from the recently-identified proSAAS precursor inhibit prohormone convertase 1 (PC1) suggesting that this novel peptide may function as an endogenous inhibitor of PC1. To further understand the role of proSAAS in vivo, we have investigated the expression of proSAAS mRNA and processing of proSAAS during pre- and early postnatal rodent development. In situ hybridization showed that, by embryonic day 12.5 (e12.5) in the rat, proSAAS mRNA was present in essentially all differentiating neurons in the mantle layer of the myelencephalon, metencephalon, diencephalon, spinal cord and several sympathetic ganglia. During later stages of prenatal development, widespread proSAAS expression continues in post-mitotic neurons of both the CNS and PNS and begins in endocrine cells of the anterior and intermediate pituitary. Although proSAAS expression overlaps with PC1 in several regions, its overall expression pattern is significantly more extensive, suggesting that proSAAS may be multifunctional during development. Processed forms of proSAAS are present by at least mid-gestation with marked accumulation of two C-terminal forms, comprising the PC1 inhibitory fragment of proSAAS.

New assumptions about oxidative processes involved in steroid hormone biosynthesis: is the role of cytochrome P-450-activated dioxygen limited to hydroxylation reactions or are dioxygen insertion reactions also possible?

The traditional conception of the chemical pathways leading to the formation of the steroid hormones is derived by piecing together the results of several independent in vitro incubation experiments. The results of these experiments have led to the assumption that some relevant cytochrome P-450's (P-450scc, P-450arom, P-450aldo, etc.) are "polyfunctional" and catalyze several successive hydroxylation reactions, which lead to the formation of the hormonal products. This essay offers an alternative view. It advances the suggestion that the oxygenated intermediates in the relevant biosynthetic conversions are reactive species that are formed by addition of both atoms of dioxygen onto two neighboring carbon atoms of steroidal precursors. Space-filled Stuart molecular models, generated by a computer program, suggest that the oxidized intermediates resemble hydroperoxides or cyclic peroxides (1,2-dioxanes). For the aromatization process required for estrogen biosynthesis, the atoms of dioxygen are bonded to C-2 and C-19 of the C19-precursor. For aldosterone formation, dioxygen is bonded to C-11 and C-18 of an appropriate precursor. Moreover, the results obtained from a computer program that provides information about "molecular mechanics" (bond angles and bond distances as well as total potential energies for each conformation of a molecule) suggest that consideration be given to the possibility that cortisol also can be biosynthesized by P-450-activated dioxygen addition to C-11 and C-17 of an appropriate precursor. Neither the traditional view of steroidogenic pathways nor the suggestions advanced here have been established by compelling experimental findings. Both hypotheses are saddled with untested assumptions, which are necessary because the dynamic processes can only be discerned by indirect means. The origins of some naturally occurring steroids hydroxylated at C-17, C-18 and C-19 are examined in the light of the suggestions made in this essay.

Cathepsin L and Arg/Lys aminopeptidase: a distinct prohormone processing pathway for the biosynthesis of peptide neurotransmitters and hormones

Peptide neurotransmitters and hormones are synthesized as protein precursors that require proteolytic processing to generate smaller, biologically active peptides that are secreted to mediate neurotransmission and hormone actions. Neuropeptides within their precursors are typically flanked by pairs of basic residues, as well as by monobasic residues. In this review, evidence for secretory vesicle cathepsin L and Arg/Lys aminopeptidase as a distinct proteolytic pathway for processing the prohormone proenkephalin is presented. Cleavage of prohormone processing sites by secretory vesicle cathepsin L occurs at the NH2-terminal side of dibasic residues, as well as between the dibasic residues, resulting in peptide intermediates with Arg or Lys extensions at their NH2-termini. A subsequent Arg/Lys aminopeptidase step is then required to remove NH2-terminal basic residues to generate the final enkephalin neuropeptide. The cathepsin L and Arg/Lys aminopeptidase prohormone processing pathway is distinct from the proteolytic pathway mediated by the subtilisin-like prohormone convertases 1/3 and 2 (PC1/3 and PC2) with carboxypeptidase E/H. Differences in specific cleavage sites at paired basic residue sites distinguish these two pathways. These two proteolytic pathways demonstrate the increasing complexity of regulatory mechanisms for the production of peptide neurotransmitters and hormones.

[Oral and gastric diffuse neuroendocrine system: discussion questions of structure and function]

In recent years, diffuse neuroendocrine system (DNES) in the digestive tract attracted worldwide attention. Cells throughout the digestive tract receive information in many forms, including chemical messengers that emanate from other cells. At the turn of XIX century, the concept of nervism or entire neural control of digestive functions, developed by Pavlov prevailed. The prototype for chemical communication came with discovery of the first hormone, secretin and histamine, a non-nervous and non-gastrin compound by L. Popielski from Lviv university. This review presents past and present advances in physiological mechanisms underlying digestion and newly recognized several groups of hormones and transmitters, that produced by digestive diffuse neuroendocrine system cells. Two-way communication pathways operate between the brain and the gut, each comprising afferent fibers signaling sensory information from the gut to the brain and efferent fibers transmitting signals in opposite direction. Short intramural and long extramural reflexes are triggered as well as various gut hormones are released by feeding that "cooperate" with the "brain-gut axis" in alteration of the digestive exocrine and endocrine secretion, motility and blood circulation and feeding behavior. Up till now, researches about gastric DNES in human and animal have been reported, but the research data about representation DNES in oral cavity are scarce. In the present paper, described ultrastructure of oral endocrinocytes from rat gum mucous by electron-microscopic analysis method. Their morphological feature provides evidence of neuroendocrine acting mode. This research can morphologically prove that the oral DNES cells is almost the same as of stomach and gut. It shows morphological evidence of representation brain -gut axis in oral cavity with an neuroendocrine-exocrine mode of peptide action. It suggests that the oral DNES play important role in the diversity of physiological functions, mucosal repair and reconstitutional process and homeostasis in oral cavity. Future investigation of oral DNES has opened new therapeutic approaches to various mucous injury-related diseases.

Endocrine function of the postmenopausal ovary

In light of recent evidence, it seems that the endocrine function of the postmenopausal ovary is more elusive and more variable than previously believed. Although the current authors believe that the postmenopausal ovary has lost a clinically significant estrogenic capability, a definitive conclusion regarding androgen production cannot be forthcoming.

Mevastatin inhibits ovarian theca-interstitial cell proliferation and steroidogenesis

OBJECTIVE

Statins reduce cardiovascular risks by improving hypercholesterolemia, reducing vascular smooth muscle proliferation, and ameliorating inflammation. Polycystic ovary syndrome (PCOS) is associated with increased cardiovascular risks and is characterized by ovarian theca-interstitial hyperplasia and hyperandrogenism. This study tested the hypothesis that mevastatin limits theca-interstitial proliferation and decreases steroidogenesis.

DESIGN

In vitro study.

SETTING

Academic laboratory.

PATIENT(S)

None.

INTERVENTION(S)

Effects of mevastatin on cultured theca-interstitial cells.

MAIN OUTCOME MEASURE(S)

Proliferation was evaluated by determination of DNA synthesis using thymidine incorporation assay and by 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide (MTT) assay. Production of P and T was determined by specific radioimmunoassays.

RESULT(S)

Mevastatin induced a profound concentration-dependent inhibition of DNA synthesis. At the highest concentration (30 microM), mevastatin inhibited DNA synthesis by 92%. Similarly, in the MTT proliferation assay, mevastatin induced a concentration-dependent decrease in cell number. Mevastatin decreased production of P (by up to 49%) and T (by up to 52%); these effects remained significant when the effect on cell culture protein content was accounted for.

CONCLUSION(S)

Mevastatin inhibits proliferation of theca-interstitial cells; it also inhibits P and T production independently of the effects on cell growth. These findings provide a foundation for studies evaluating statins as potential therapeutic agents in the treatment of ovarian mesenchymal hyperplasia and hyperandrogenism characteristic of PCOS.

Neurosteroids: the StAR protein in the brain

The nervous system is a well-known target for steroid hormones, as these hormones regulate brain functions that include neuronal survival and differentiation, myelination, neurogenesis, plasticity and repair after injury. Furthermore, the brain is also a steroidogenic tissue because it possesses the enzymes required to metabolize the common precursor, cholesterol, into steroids, named 'neurosteroids'. The rate-limiting step in the synthesis of steroid hormones is the access of cholesterol, accumulated in the outer mitochondrial membrane, to the first steroidogenic enzyme, P450scc (cholesterol side-chain cleavage enzyme), located in the inner mitochondrial membrane. In the ovary and the adrenal gland, which comprise classic steroidogenic tissues, this process requires the steroidogenic acute regulatory protein (StAR) to facilitate the shuttle of cholesterol through the intermembrane space. The mechanism used by the brain to regulate the first stage of steroidogenesis remains unknown. Recently, several groups have investigated the potential presence of StAR in the nervous tissue and have concluded that StAR is widely expressed throughout the brain, although restricted to specific cell populations. New results concerning localization, regulation and possible functions of StAR in the brain are discussed.

Depletion of ovarian reserve in young women after treatment for cancer in childhood: detection by anti-Müllerian hormone, inhibin B and ovarian ultrasound

BACKGROUND

Treatment of cancer during childhood may result in loss of primordial follicles from the ovary.

METHODS

Ten cancer survivors and 11 controls with regular menstrual cycles, in addition to 10 cancer survivors and 10 controls taking the combined oral contraceptive pill (COCP) were recruited. Subjects were investigated on days 3-5 of a menstrual cycle, or week 3 of COCP administration before and 24 h after administration of 225 IU FSH.

RESULTS

Serum FSH levels were elevated in cancer survivors with regular menstrual cycles (7.5 +/- 1.4 versus 4.2 +/- 0.3 IU/l; P = 0.02), while anti-Müllerian hormone (AMH) levels were lower (13.0 +/- 3.0 versus 21.0 +/- 3.4 pmol/l; P < 0.05). Other hormone levels were unchanged. Ovarian volume was smaller in cancer survivors than controls (3.0 +/- 0.5 versus 5.0 +/- 0.8 ml; P < 0.05), but antral follicle count (AFC) was similar. During COCP administration, inhibin B remained undetectable in six cancer survivors after FSH administration, whereas all controls showed a rise in inhibin B levels. The AFC was lower in cancer survivors than in controls (4.2 +/- 0.8 versus 7.2 +/- 0.8; P = 0.02). Ovarian volume was low in both groups, but did not differ between them.

CONCLUSIONS

The study results demonstrate both hormonal and biophysical evidence of partial loss of the ovarian reserve in young cancer survivors. This was detected both in women with normal menstrual cycles and during COCP administration.

Obesity and the metabolic syndrome

The metabolic syndrome is a cluster of risk factors for coronary heart disease that seemingly have an underlying metabolic causation. Central obesity is the centerpiece of the metabolic alterations. Accordingly, increased abdominal adiposity contributes to dyslipidemia, hyperglycemia, and hypertension. In about 20% of the cases with metabolic syndrome, there is also beta-cell dysfunction that leads to the clinical manifestation of diabetes mellitus. Recent evidence suggests that increased obesity is also associated with inflammation. The role of adipose tissue in the causation of metabolic alterations that lead to the clinical manifestation of the metabolic syndrome has become a focus of active research. Adipose tissue not only secretes non-esterified fatty acids that contribute to atherogenic dyslipidemia, steatosis and lipotoxicity. This organ is also an active endocrine and paracrine system. It can secrete pro-inflammatory factors, pro-insulin resistance factors, and other cytokines and hormones that can contribute to hypertension and impaired fibrinolysis. Therefore, the metabolic alterations commonly associated with increased central obesity of the metabolic syndrome are pro-atherogenic partly because the metabolites are proinflammatory.

Developmental effects of embryonic exposure to toxaphene in the American alligator (Alligator mississippiensis)

A variety of organochlorine pesticides have been shown to adversely affect embryonic development. A number of abnormalities have been documented in alligators (Alligator mississippiensis) from highly-contaminated Lake Apopka, FL, USA that are similar to the results of experimental studies exposing embryos to pesticides. In the current study, we exposed developing alligator embryos to varying concentrations of toxaphene, a broad-spectrum pesticide found in relatively high concentration in Lake Apopka alligator egg yolk. The toxaphene, dissolved in 50 microl of ethanol, was applied topically to the eggshell just prior to the sex-determining period of development. Shortly after hatching, we examined a number of morphological and physiological endpoints to determine the consequences of sub-lethal embryonic exposure to toxaphene. Our results indicate that toxaphene had little or no effect on the morphological endpoints examined including body mass (BM) and size, liver, thyroid, and gonad development. In addition, toxaphene failed to affect sexual differentiation, or in vitro thyroxin, testosterone (T), and estradiol production. However, male plasma T concentration was higher in animals treated with 10 and 0.01 microg toxaphene/kg (based on mean egg mass) than control males. Because in vitro T production was not different among control groups, we suggest the difference in plasma T could be due to differences in hypothalamic-pituitary stimulation of the gonad or hepatic steroid degradation. This study indicates that technical grade toxaphene, at the applied doses, does not induce the same developmental abnormalities associated with alligators living in Lake Apopka. Future studies should consider the effects of embryonic exposure to a mixture of chemicals, including toxaphene metabolites, on development in alligators to better evaluate the consequences of environmental contamination.

Early Career Award. Clarifying the emotive functions of asymmetrical frontal cortical activity

Asymmetrical activity over the frontal cortex has been implicated in the experience and expression of emotions and motivations. Explanations of the research have suggested that relatively greater left frontal activity is associated with positive affect and/or approach motivation, and that relatively greater right frontal activity is associated with negative affect and/or withdrawal motivation. In past research, affective valence and motivational direction were confounded, as only positive (negative) affects that were associated with approach (withdrawal) motivation were examined. Consequently, this research is unable to address whether asymmetrical frontal activity is associated with affective valence, motivational direction, or some combination of valence and motivation. In this article, I review research on the emotion of anger, a negative emotion often associated with approach motivation, that suggests that asymmetrical frontal cortical activity is due to motivational direction and not affective valence. Methodological and theoretical implications for the study of the frontal asymmetry specifically, and for emotion and motivation more generally, are discussed.

Blunted hypothalamic neuropeptide gene expression in response to fasting, but preservation of feeding responses to AgRP in aging male Brown Norway rats

Aging mammals lose the ability to maintain energy balance, exhibiting decreased appetite (anorexia) and impaired ability to maintain body weight. To determine the contribution of hypothalamic neuropeptides, two experiments were performed in male Brown Norway rats. To assess the hypothalamic neuropeptide response to food deprivation, young (Y; 4 mo old), middle-aged (M; 13 mo), and old (O; 25 mo) rats were either ad libitum fed or fasted for 72 h (n = 10/group) and killed. Hypothalamic levels of agouti-related peptide (AgRP), proopiomelanocortin (POMC), and cocaine-amphetamine-regulated transcript (CART) mRNA were assessed by in situ hybridization. With aging, arcuate AgRP gene expression decreased and CART mRNA increased, but POMC mRNA did not change. Fasting-induced changes in gene expression of all neuropeptides studied were attenuated with aging. To test the food intake response to appetite-stimulating neuropeptides, Y, M, O, and very old (VO; 33 mo) rats (n = 4-8/group) received one intracerebroventricular injection of each of three treatments: 0.1 nmol AgRP, 2.34 nmol NPY, and saline control. AgRP increased food intake of all groups by 10-20%, compared with saline, and this effect persisted up to 7 days after injection. VO animals were more sensitive to the effects of AgRP than younger animals. In contrast, NPY increased food intake more in Y than in older animals and its effects did not last >24 h. We conclude that the mechanisms by which arcuate nucleus neurons influence appetite are differentially affected by age and speculate that the melanocortin system may be a useful target for treatment of the anorexia of aging.

[Adipose tissue: a real endocrine gland synthesizing hormones and cytokines: clinical implications]

Adipose tissue (AT) is not considered anymore as a passive depot for storing excess energy in the form of triglycerides but as an active organ secreting several hormones or adipokines. With the exception of adiponectin the serum levels of adipokines are increased in obesity. Leptin regulates food intake, reproductive and immune system. Adiponectin decreases insulin resistance and has antiinflammatory properties. On the contrary, resisting, tumor necrosis factor and Interleukin-6 are diabetogenic and induce inflammatory reactions. It is believed that atherosclerosis is due to the inflammation induced by oxydized LDL-cholesterol in vessels. Abdominal obesity is associated with increased incidence of metabolic disorders and insulin resistance. The role of adipokines in these disorders is described as well as their role in the antidiabetic effect of thiazo-linedinediones. AT contains also enzymes responsible for the aromatization of androstenedione into estrone, which could explain an increase of breast and uterus cancer in obese people.

[New steroid hormone family: endogenous cardiac glycosides and their role in physiologic and pathologic conditions]

In the last two decades extensive study has been carried out on the isolation, identification and biosynthesis of the "endogenous digitalis-like compounds" whose physiological and pathophysiological functions are only starting to be understood. Besides ouabain (strophanthin) and digoxin, four further endogenous cardiac glycosides were isolated and identified so far. These compounds are found in almost all mammalian tissues, including blood plasma and urine, but with the highest concentrations in the adrenal gland, pituitary and hypothalamus. De novo biosynthesis of these glycosides occurs in zona fasciculata cells of adrenal glands, precursors such as progesterone, pregnenolone, and rhamnose increase the synthesis of the ouabain-like immunoreactive material. The secretion of these compounds from the adrenocortical cells are controlled by adrenerg mechanisms, as well as via the renin-angiotensin system. The hydrophobic cardiac glycosides are transported in blood as complexes bound to specific binding globulins. The identified endogenous cardiac glycosides fulfill all the postulated criterions of the hormones, so they represent a new class of steroid hormones. The cardiac glycosides influence the active sodium pump, indirectly the intracellular free calcium concentration and therefore exert a positive inotropic effect on cardiac muscle. Furthermore, in physiological concentrations they can regulate the cell growth and protein synthesis inducing activation of intracellular signal pathways. Under pathological conditions, however, when the concentration of these steroids are high, they play a crucial role in the development of different serious illnesses such as essential hypertension as well as congestive heart failure. Further intensive investigations are needed to clarify some contradictory details accumulated during the last few years in this field.

Secretion of locally synthesized neurohormone from neurites of peptidergic neurons

Local protein synthesis in neuronal processes is a common phenomenon and may play an important role in synaptic plasticity and hormonal regulation. We have used neuroendocrine bag cells of Aplysia californica as a model system to study local protein synthesis. In our previous work we found that bag cell neurites are capable of synthesizing and processing the prohormone of egg-laying hormone (pro-ELH). In the present study, we found that bag cell neurites are also capable of releasing locally synthesized pro-ELH and ELH-related products via both constitutive and regulated pathways. However, an electrical afterdischarge did not enhance local pro-ELH synthesis, as it does in the bag cell soma. This is the first evidence that isolated neurites are capable of secreting locally synthesized proteins.