Male minipuberty involves the gonad-independent activation of preoptic nNOS neurons.

BACKGROUND: The maturation of the hypothalamic-pituitary-gonadal (HPG) axis is crucial for the establishment of reproductive function. In female mice, neuronal nitric oxide synthase (nNOS) activity appears to be key for the first postnatal activation of the neural network promoting the release of gonadotropin-releasing hormone (GnRH), i.e. minipuberty. However, in males, the profile of minipuberty as well as the role of nNOS-expressing neurons remain unexplored. METHODS: nNOS-deficient and wild-type mice were studied during postnatal development. The expression of androgen (AR) and estrogen receptor alpha (ERα) as well as nNOS phosphorylation were evaluated by immunohistochemistry in nNOS neurons in the median preoptic nucleus (MePO), where most GnRH neuronal cell bodies reside, and the hormonal profile of nNOS-deficient male mice was assessed using previously established radioimmunoassay and ELISA methods. Gonadectomy and pharmacological manipulation of ERα were used to elucidate the mechanism of minipubertal nNOS activation and the maturation of the HPG axis. RESULTS: In male mice, minipubertal FSH release occurred at P23, preceding the LH surge at P30, when balanopreputial separation occurs. Progesterone and testosterone remained low during minipuberty, increasing around puberty, whereas estrogen levels were high throughout postnatal development. nNOS neurons showed a sharp increase in Ser1412 phosphorylation of nNOS at P23, a phenomenon that occurred even in the absence of the gonads. In male mice, nNOS neurons did not appear to express AR, but abundantly expressed ERα throughout postnatal development. Selective pharmacological blockade of ERα during the infantile period blunted Ser1412 phosphorylation of nNOS at P23. CONCLUSIONS: Our results show that the timing of minipuberty differs in male mice when compared to females, but as in the latter, nNOS activity in the preoptic region plays a role in this process. Additionally, akin to male non-human primates, the profile of minipuberty in male mice is shaped by sex-independent mechanisms, and possibly involves extragonadal estrogen sources.

1H NMR Metabolic Profile of Scyphomedusa Rhizostoma pulmo (Scyphozoa, Cnidaria) in Female Gonads and Somatic Tissues: Preliminary Results.

The Mediterranean basin is one of the regions heavily affected by jellyfish bloom phenomena, mainly due to the presence of scyphozoans, such as Rhizostoma pulmo. The jellyfish have few natural predators, and their bodies represent an organic-rich substrate that can support rapid bacterial growth with great impact on the structure of marine food webs. In Asiatic countries, jellyfish are widely studied for their health benefits, but their nutritional and nutraceutical values still remain poorly characterized. In this study, the differences in the 1H NMR spectroscopy metabolic profiles of R. pulmo female gonads and body fractions (including umbrella and oral arms), in different sampling periods, were studied. For each body compartment both lipid and aqueous extracts were characterized and their 1H NMR metabolic profiles subjected to multivariate analysis. From a statistical analysis of the extracts, a higher contents of ω-3 polyunsaturated fatty acids (PUFAs), amino acid and osmolytes (homarine, betaine, taurine) with important roles in marine invertebrates were observed in female gonads, whereas umbrella and oral arms showed similar metabolic profiles. These results support a sustainable exploitation of the jellyfish for the extraction of bioactive compounds useful in nutraceutical, nutricosmetics, and functional food fields.

Pharmacokinetics of Sodium Selenite in Rat Plasma and Tissues After Intragastric Administration.

The purpose of this research is to investigate the absorption, distribution, excretion, and pharmacokinetics of selenite in rats after intragastric administration, and thus illustrate the efficiency of selenium (Se) supplementation. After a single gavage of sodium selenite, a concentration of Se in plasma and tissues was determined by inductively coupled plasma mass spectrometry (ICP-MS) at different time points. Through fitting the data with the metabolic kinetic model, the corresponding kinetic parameters were determined for plasma and tissues, including kidney, liver, heart, muscle, and gonad. While the metabolic kinetics of sodium selenite in plasma, liver, and kidney of rats was well reflected by a two-compartment open model, that in heart and gonad was fitted to a one-compartment open model, and that in muscle was fitted to a one-compartment open model with a lag time. The results indicate that sodium selenite was absorbed by plasma and tissues quickly and was eliminated slowly after intragastric administration. Based on the results, we propose that multi-supplementation of Se with low dosage is superior to single supplementation with high dosage, in terms of avoiding selenosis.

[Preliminary study on changes of sex steroid hormones in periodic development of Whitmania pigra gonad].

The present study was conducted to investigate the rule of sex steroid hormones dynamic in the periodic development of Whitmania pigra gonad. The dynamic of sex steroid hormones in different age of Wh. pigra were detected by enzymolysis, extraction and UPLC-MS/MS. The results showed that the concentrations of estrone, estriol, testosterone and progesterone in the Wh. pigra showed M-type curve and peaked in 6-month-old Wh. pigra. The concentrations of above-mentioned four steroid hormones were the lowest in 9-month-old and then increased slightly. The another peaks of testosterone and progesterone were found in 2-month-old and the another peaks of estrone and estriol were obtained in 8-month-old. The concentrations of testosterone and progesterone are slightly higher than estriol during 1-month-old to 4-month-old, and thereafter strone and estriol showed higher concentration than testosterone and progesterone. In summary, the concentrations of four sex steroid hormones in Wh. pigra increased gradually with the maturation of gonads and decreased rapidly after the discharge period, which indicated that the ratio between estrogen, androgen and progesterone may be greatly related to the specificity of gonad development.

Seasonal variability of diet and trophic level of the gelatinous predator Pelagia noctiluca (Scyphozoa).

Jellyfish populations apparently have increased in some places around the world and human problems with them also have increased. However, effects of jellyfish outbreaks in the ecosystems remain poorly understood and little or no information is available on their dietary preferences - in relation to the seasonal shifts of prey abundance - and on the potential variability of their impact on marine food webs. The mauve stinger Pelagia noctiluca (Forsskål, 1775) is by far the most common outbreak-forming scyphozoan jellyfish in the Western Mediterranean. By use of a combination of stomach contents, stable isotope (SI) and fatty acid (FA) analyses, we tested the hypothesis that changes in the seasonal dietary sources of P. noctiluca parallel changes in the FA and SI composition. Stomach content and biomarker analyses suggested that P. noctiluca is not a selective predator, cyclically shifting between carnivory and omnivory depending on the seasonality of accessible prey. The combination of SI and FA analyses highlighted the importance of microzooplankton as prey. Specific FA biomarkers showed that the diet of P. noctiluca changed seasonally depending on the availability of living plankton or suspended detritus. This study also revealed significant biochemical differences between jellyfish somatic and gonadal tissues, with total fatty acid concentration in the gonads up to ten times higher than in the somatic tissues.

Separation and Characterization of Antioxidative and Angiotensin Converting Enzyme Inhibitory Peptide from Jellyfish Gonad Hydrolysate.

The gonad of jellyfish (RhopilemaesculentumKishinouye), containing high protein content with a rich amino acid composition, is suitable for the preparation of bioactive peptides. Jellyfish gonad was hydrolysed with neutral protease to obtain jellyfish gonad protein hydrolysate (JGPH), which was then purified sequentially by ultrafiltration, gel filtration chromatography, and RP-HPLC. The peptides were characterized with HPLC-MS/MS. One peptide with amino acid sequence Ser-Tyr (SY) was identified and synthesized, which showed good ACE inhibitory and antioxidant activity. The IC50 of this peptide on DPPH, ·OH, super oxygen anion scavenging activities, and ACE inhibitory activity are 84.623 µM, 1177.632 µM, 456.663 µM, and 1164.179 µM, respectively. The anchor in the binding site of SY and ACE C-domain (ACE-C) was obtained by molecular simulations. The results showed that the dipeptide purified from jellyfish gonad protein hydrolysates can be used as functional food material and is helpful in the study of antioxidant and inhibition of ACE.

The Sea Urchin Arbacia lixula: A Novel Natural Source of Astaxanthin.

Several echinoderms, including sea urchins, are valuable sources of bioactive compounds but their nutraceutical potential is largely unexplored. In fact, the gonads of some sea urchin species contain antioxidants including carotenoids and polyhydroxylated naphthoquinones (PHNQ's), such as echinochrome A. Astaxanthin is known to have particular bioactivity for the prevention of neurodegenerative diseases. This carotenoid is produced by microalgae, while several marine invertebrates can bioaccumulate or synthetize it from metabolic precursors. We determined the carotenoid content and analyzed the bioactivity potential of non-harvested Atlantic-Mediterranean sea urchin Arbacia lixula. The comparison of methanol crude extracts obtained from eggs of farmed and wild specimens revealed a higher bioactivity in farmed individuals fed with a customized fodder. HPLC-analysis revealed a high concentration of astaxanthin (27.0 µg/mg), which was the only pigment observed. This study highlights the potential of farmed A. lixula as a new source of the active stereoisomer of astaxanthin.

Sterilization of sterlet Acipenser ruthenus by using knockdown agent, antisense morpholino oligonucleotide, against dead end gene.

Sturgeons (chondrostean, acipenseridae) are ancient fish species, widely known for their caviar. Nowadays, most of them are critically endangered. The sterlet (Acipenser ruthenus) is a common Eurasian sturgeon species with a small body size and the fastest reproductive cycle among sturgeons. Such species can be used as a host for surrogate production; application is of value for recovery of critically endangered and huge sturgeon species with an extremely long reproductive cycle. One prerequisite for production of the donor's gametes only is to have a sterile host. Commonly used sterilization techniques in fishes such as triploidization or hybridization do not guarantee sterility in sturgeon. Alternatively, sterilization can be achieved by using a temporary germ cell exclusion-specific gene by a knockdown agent, the antisense morpholino oligonucleotide (MO). The targeted gene for the MO is the dead end gene (dnd) which is a vertebrate-specific gene encoding a RNA-binding protein which is crucial for migration and survival of primordial germ cells (PGCs). For this purpose, a dnd homologue of Russian sturgeon (Agdnd), resulting in the same sequence in the start codon region with isolated fragments of sterlet dnd (Ardnd), was used. Reverse transcription polymerase chain reaction confirmed tissue-specific expression of Ardnd only in the gonads of both sexes. Dnd-MO for depletion of PGCs together with fluorescein isothiocyanate (FITC)-biotin-dextran for PGCs labeling was injected into the vegetal region of one- to four-cell-stage sterlet embryos. In the control groups, only FITC was injected to validate the injection method and labeling of PGCs. After optimization of MO concentration together with volume injection, 250-µM MO was applied for sterilization of sturgeon embryos. Primordial germ cells were detected under a fluorescent stereomicroscope in the genital ridge of the FITC-labeled control group only, whereas no PGCs were present in the body cavities of morphants at 21 days after fertilization. Moreover, the body cavities of MO-treated and nontreated fish were examined by histology and in situ hybridization, showing gonads which had no germ cells in morphants at various stages (60, 150, and 210 days after fertilization). Taken together, these results report the first known and functional method of sturgeon sterilization.

Developmental exposure to the organophosphorus flame retardant tris(1,3-dichloro-2-propyl) phosphate: estrogenic activity, endocrine disruption and reproductive effects on zebrafish.

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is an organophosphate flame retardant that is detectable in the environment and biota, prompting concern over its risk to wildlife and human health. Our objective was to investigate whether long-term exposure to low concentrations of TDCPP can affect fish reproduction. Zebrafish embryos were exposed to low concentrations (0, 4, 20 and 100µg/L) of TDCPP from 2h post-fertilization until sexual maturation. Exposure to TDCPP significantly increased plasma estradiol and testosterone levels in females, but had no effect in males. TDCPP exposure also caused a significant reduction in fecundity as indicated by decreased egg production. Real-time PCR was performed to examine selected genes in the hypothalamic-pituitary-gonadal (HPG) axis and liver. Principle component analysis (PCA) showed that sex hormone levels and fecundity were related to the mRNA level of several genes in the HPG axis. Furthermore, hepatic vitellogenin (vtg1 and vtg3) expression was upregulated in both females and males, suggesting TDCPP has estrogenic activity. Histological examination revealed promotion of oocyte maturation in the females, but retardation of spermiation in males. Reduced egg quality (e.g., egg diameter) and increased malformation rates were observed in the F1 generation. Chemical analysis showed significant levels of TDCPP and its metabolite bis(1,3-dichloro-2-propyl) phosphate in the gonads of males and females. In conclusion, long-term exposure to low concentrations of TDCPP impairs fish reproduction.

Effects of depleted uranium on the reproductive success and F1 generation survival of zebrafish (Danio rerio).

Despite the well-characterized occurrence of uranium (U) in the aquatic environment, very little is known about the chronic exposure of fish to low levels of U and its potential effect on reproduction. Therefore, this study was undertaken to investigate the effects of environmental concentrations of depleted U on the reproductive output of zebrafish (Danio rerio) and on survival and development of the F1 embryo-larvae following parental exposure to U. For that purpose, sexually mature male and female zebrafish were exposed to 20 and 250 µg/L of U for 14 days and allowed to reproduce in clean water during a further 14-day period. At all sampling times, whole-body vitellogenin concentrations and gonad histology were analyzed to investigate the effects of U exposure on these reproductive endpoints. In addition, accumulation of U in the gonads and its genotoxic effect on male and female gonad cells were quantified. The results showed that U strongly affected the capability of fish to reproduce and to generate viable individuals as evidenced by the inhibition of egg production and the increased rate of mortality of the F1 embryos. Interestingly, U exposure resulted in decreased circulating concentrations of vitellogenin in females. Increased concentrations of U were observed in gonads and eggs, which were most likely responsible for the genotoxic effects seen in fish gonads and in embryos exposed maternally to U. Altogether, these findings highlight the negative effect of environmentally relevant concentrations of U which alter the reproductive capability of fish and impair the genetic integrity of F1 embryos raising further concern regarding its effect at the population level.

Evaluation of antibacterial, antifungal and cytotoxic effects of Holothuria scabra from the North Coast of the Persian Gulf.

Bioactive compounds of the gonad, respiration tree, and body wall of the sea cucumber Holothuria scabra collected from the North Coast of the Persian Gulf were extracted using ethyl acetate, methanol and water-methanol mixtures. Extracts were evaluated for their antibacterial and antifungal activities against Aspergillus niger, Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The activity was determined using the disc diffusion test. Cytotoxic activities of the extracts were determined by brine shrimp lethality assay. Results showed the existence of an antifungal activity of all extracts against A. niger with MIC ranging from 3 to 9µg/mL. The highest antifungal activity was found in respiration tree (methanol) with an inhibition zone of about 50mm against A. niger at 18µg/mL extract concentration. Cytotoxic activity was obtained for methanolic extracts only. Methanol extract of the gonads showed the highest cytotoxic effect (LC50=50.5µg/mL) continuing with RT methanol extract (LC50=70µg/mL).

Effects of dietary fish oil replacement with flaxseed oil on tissue fatty acid composition and expression of desaturase and elongase genes.

BACKGROUND: This study was conducted to evaluate the effects of total or partial substitution of dietary fish oil (FO) by flaxseed oil (FlaxO) in Jade Tiger hybrid abalone on fatty acid composition of muscle, gonad and digestive gland, and the expression of desaturase and elongase genes. Abalone were fed five different experimental diets in which FO (control diet) was serially replaced by 25%, 50%, 75% and 100% FlaxO respectively. RESULTS: Muscle, gonad and digestive gland of abalone fed the control diet and the diets containing 25%, 50% and 75% FlaxO showed significantly higher (P < 0.05) levels of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) compared to those fed the 100% FlaxO. The results also showed that Δ-6 desaturase and elongase gene expression in muscle was increased in a graded manner by increasing dietary FlaxO. The expression of both genes was higher in abalone fed the FlaxO-substituted diets compared to the abalone fed FO. CONCLUSION: The replacement of FO with FlaxO in commercial abalone diets at levels of 25-75% can improve the composition of health-benefiting n-3 polyunsturated fatty acids in tissues of cultured hybrid abalone, and achieve similar outcomes to FO supplementation.

Hormones in the mentally disturbed brain: steroids and peptides in the development and treatment of psychopathology.

One of the more fascinating recent discoveries in neuroscience is the widespread influence of hormones on brain regions and functions underlying pathological behaviors. A story is unfolding that points to critical roles played by hypothalamic - pituitary - gonadal (HPG) and hypothalamic - pituitary - adrenal (HPA) axes on a startling array of mental disorders, from depression to dementia. The influence of peptides and steroids does not end with hormones released from the two axes, however. It is now clear that the brain has adapted, "highjacked" is more descriptive, HPG and HPA hormones for uses unrelated to their original functions in reproduction and responses to stress. Findings of neuromodulatory effects of HPA and HPG hormones on monoamine, GABA, glutamate and opioid pathways and of hormone receptors and enzymes involved in hormone synthesis, particularly of steroids, in the hippocampus, amygdala and other subcortical brain regions provide the brain with multiple evolutionary means to adapt to new functions. The complexity of the metabolic cascade for the steroids also leaves open mechanisms by which endogenous errors and exogenous chemicals could be involved in the etiology of psychopathologies. The planned review will examine the recent literature for evidence of steroidal and peptidergic influences on basic biological functions and on mood disorders, anxiety and PTSD, schizophrenia, substance abuse and dementia. Emphasis will be placed on animal models, although findings with patient populations will be prominently included. Special attention will be paid to novel pathways by which the precursors and metabolites of sex steroids can influence psychopathologies. We also will speculate on promising treatments with hormone modulators that may be useful in mollifying the symptomology of the mental disorders.

Nutritional quality of the edible tissues of European lobster Homarus gammarus and American lobster Homarus americanus.

The clawed lobsters Homarus gammarus and Homarus americanus are high-priced and appreciated food items in southern Europe. From a nutritional point of view there is still limited information on the chemical composition of edible tissues (muscle, hepatopancreas, and gonads) of both species. Therefore, the aims of the present work were to study the proximate chemical composition, energy, fatty acid and amino acid profiles, and cholesterol content in each edible tissue of both species and to evaluate their nutritional quality. Differences were observed between tissues, sexes, and species. Muscle and gonads were rich in protein, whereas hepatopancreas had high fat, cholesterol, and energy contents. All edible tissues were valuable sources of essential amino acids. Contrary to the common belief that shellfish consumption should be reduced in a low-fat and -cholesterol diet, all edible tissues of clawed lobsters have a nutritious value perfectly compatible with nutritious and healthy diets.

Correlation of nitric oxide (NO) activity and gonadal function in Japanese quail, Coturnix coturnix japonica following temporal phase relation of serotonergic and dopaminergic oscillations.

Nitric oxide (NO), a highly reactive and short-lived radical, is considered to be an important trigger molecule for several physiological mechanisms including gonadotrophin releasing hormone (GnRH) secretion in mammals, although there is no such information in avian literature. On the other hand, specific temporal phase relation of circadian neural (serotonergic and dopaminergic) oscillations is reported to modulate reproductive activity in many avian species including Japanese quail. The present study was undertaken to investigate the correlation of NO activity and gonadal function of Japanese quail. In experiment I, the effect of serotonin and dopamine precursors, (5-hydroxytryptophan (5-HTP) and L-dihydroxyphenyalanine (L-DOPA) respectively; 5 mg per 100g body weight) administered at intervals of 8 or 12h over a period of 13 days, was studied on reproductive responses and NO activity. Measurements of body weight, cloacal gland size, testosterone concentration, spermatogenesis, nitrite-nitrate concentration in plasma, hypothalamus and testes, and NADPH-diaphorase (NADPH-d) activity in testes were made on the 2nd, 3rd, 6th and 11th days of treatment and 2nd and 30th day post-treatment. In experiment II, quail were divided into five groups including the control. One experimental group received 13 daily injections of 5-HTP and L-DOPA at intervals of 8h along with 0.1 ml of normal saline administered orally (8-hr+Veh), while another group of 8-hr quail received NO donor (sodium nitroprusside (SNP), 5 mg per 100 g body weight) orally (8-hr+SNP). The third experimental group received 5-HTP and L-DOPA at intervals of 12h along with normal saline (12-hr+Veh), while the fourth group of quail along with 5-HTP and L-DOPA at intervals of 12h also received the NOS inhibitor (N-nitro-L-arginine methyl ester, L-NAME, 25 microg per 100 g body weight) intraperitoneally (12-hr+L-NAME) for 13 days. This experiment was terminated after 21 days of the treatment. Results indicate that 5-HTP and L-DOPA administered 8h apart (8-hr) suppressed but if given 12h apart (12-hr) stimulated the reproductive system and NO activity compared to the control. These effects were apparent on the 6th day of injections and were maintained 30 days following the termination of the treatment. A significant decrease in nitrite and nitrate concentration and NADPH-d activity in reproductively inhibited 8-hr group and an increase in reproductively stimulated 12-hr quail was also evident. In contrast, these activities were stimulated in 8-hr+SNP quail and were suppressed in 12-hr+L-NAME group quail. It is concluded that activity of the reproductive system and NO activity waxes and wanes simultaneously in Japanese quail. Moreover, experimental modulation of gonadal activity (following changes in the phase relation of serotonergic and dopaminergic activity) or NO activity (following the administration of NO modulator or inhibitor) affects each other maintaining a parallel relation between the two systems. Further, it is interesting to note that the gonado-stimulatory effect of SNP overpowers the gonado-inhibitory effects of the 8-hr time interval and inhibitory effects of L-NAME mask the stimulatory effects of 12-hr temporal relation of 5-HTP and L-DOPA administration. These findings strongly suggest that reproductive effects may be induced via changes in NO activity, however the exact mechanism by which NO drives gonadal axis needs to be ascertained.

Fatty acids in liver, muscle and gonad of three tropical rays including non-methylene-interrupted dienoic fatty acids.

Scientific investigation of lipids in Elasmobranchs has been conducted mainly on shark species. Because rays seem to be neglected, this study was performed to examine the complete fatty acid (FA) composition with a particular interest for long-chain polyunsaturated FA (PUFA) content in different tissues of three ray species including parts usually discarded. The total FA and PUFA profiles of total lipids were determined in muscle, liver, and gonad of Rhinobatos cemiculus, Rhinoptera marginata, and Dasyatis marmorata, the most often caught ray species from the East Tropical Atlantic Ocean. Fifty FA were characterized as methyl esters and N-acyl pyrrolidides by gas chromatography/mass spectrometry, showing significant levels of 20:5n-3 (EPA) (up to 5.3%) and 22:5n-3 (DPA) (up to 7.3%), high levels of 20:4n-6 arachidonic (ARA) (4.8-8.6% of total FA) and 22:6n-3 (DHA) (up to 20.0%). The results show that muscle, liver and gonad of rays can provide high amounts of essential PUFA, specially DHA, for direct human nutrition or the food processing industry. High proportions of DHA were particularly found in all samples of R. cemiculus (11.6-20.0%), and in muscle and liver of D. marmorata (11.1-16.1%). Regarding the high amounts of (n-3) PUFA, this study shows that these rays deserve a better up-grading, including the normally discarded parts, and describes the occurrence of unusual NMID FA in all tissues studied. Five non-methylene-interrupted dienoic fatty acids (NMID FA) (0-3.4%) were reported, including previously known isomers, namely 20:2 Delta7,13, 20:2 Delta7,15, 22:2 Delta7,13, 22:2 Delta7,15, and new 22:2 Delta6,14. These acids are quite unusual in fish and unprecedented in rays. The 22:2 Delta6,14 acid occurred in gonads of male specimens of R. cemiculus at 2.9%.

Content of phylloquinone and menaquinone in the tissues of mummichog Fundulus heteroclitus fed diets containing different forms of vitamin K.

The contents of vitamin K in the plasma and tissues (kidney, liver and gonad) of mummichog Fundulus heteroclitus fed diets supplemented with different vitamin K groups were determined. The vitamin K mainly detected in the gastrointestinal tract of each experimental group was the one supplemented in the respective diet, and all other forms of vitamin K were observed at low concentrations. This implies that the main vitamin K source for mummichog is their food. Further evidence that the main vitamin K source is the food is that the elevation of vitamin K concentrations in the plasma and other tissues in this experiment was brought about by vitamin K added to the feed. The phylloquinone-rich diet raised the phylloquinone concentration in the plasma and the tissues much higher than the diets supplemented with short and/or long chain menaquinones. This indicates that phylloquinone is more easily accumulated into the body of fish than the menaquinone homologues. There were apparent differences in absorption and deposition of vitamin K between females and males. This may be a factor in the high mortality in male mummichog during the spawning season but further clarification of the causes of the mortality is required.

Effects of acute and chronic gonadectomy on the catecholamine innervation of the cerebral cortex in adult male rats: insensitivity of axons immunoreactive for dopamine-beta-hydroxylase to gonadal steroids, and differential sensitivity of axons immunoreactive for tyrosine hydroxylase to ovarian and testicular hormones.

Previous studies have shown that gonadectomy in adult male rats induces a complex series of region- and time-specific changes in the density of presumed cerebral cortical dopamine axons that are immunoreactive for tyrosine hydroxylase. The present study asked whether noradrenergic cortical afferents also show hormone sensitivity by assaying axons immunoreactive for the enzyme dopamine-beta-hydroxylase in representative areas of acutely and chronically gonadectomized and sham-operated adult male rats. Catecholamine afferents (both tyrosine hydroxylase-immunoreactive and dopamine-beta-hydroxylase-immunoreactive) were also quantified in gonadectomized rats supplemented with testosterone propionate, with 17-beta-estradiol, or with 5-alpha-dihydrotestosterone. Analyses of noradrenergic (dopamine-beta-hydroxylase) afferents revealed no differences in axon appearance or density among the hormonally intact and hormonally manipulated groups. However, analyses of tyrosine hydroxylase immunoreactivity revealed an unexpected division of labor among ovarian and testicular hormones in ameliorating the effects of acute verses chronic hormone deprivation on these afferents. Estradiol replacement attenuated the decreases in immunoreactivity induced by acute gonadectomy, but was ineffective in suppressing changes in immunoreactivity stimulated by chronic gonadectomy. In contrast, supplementing gonadectomized animals with dihydrotestosterone provided no protection from acute decreases in innervation, but fully attenuated both the supragranular decreases and infragranular increases in tyrosine hydroxylase-immunoreactive axon density that mark the association cortices of chronically gonadectomized rats. Together these findings indicate both long- and short-term effects of gonadectomy on cortical catecholamines, principally target dopamine afferents, and that chronic gonadectomy, which selectively disturbs dopamine innervation in the prefrontal cortices, involves a compromise in androgen signaling pathways.

Astaxanthin and its metabolites idoxanthin and crustaxanthin in flesh, skin, and gonads of sexually immature and maturing Arctic charr (Salvelinus alpinus (L.)).

Carotenoid compositions of the flesh, skin, and ovaries were determined in sexually maturing and immature Arctic charr (Salvelinus alpinus) fed diets supplemented with astaxanthin (optical isomer ratio (3S,3'S):(3R,3'S; meso):(3R,3'R); 1:2:1). Astaxanthin comprised 64-79% of the flesh carotenoids, and the 3',4'-cis and 3',4'-trans glycolic isomers of idoxanthin, present in a 1:1 ratio, represented 20-35%. The flesh of the sexually maturing charr contained relatively more idoxanthin than that of sexually immature fish (20 vs 35% of total carotenoids), possibly being indicative of a higher metabolic turnover of astaxanthin in the latter. The relative proportions of flesh carotenoids were unaffected by sex. The relative carotenoid composition of ovaries was similar in sexually maturing and immature females. The 3',4'-cis and 3',4'-trans glycolic isomers of idoxanthin (ratio 0.7:1) were the major carotenoids (56% of total), followed by crustaxanthin (20%), and astaxanthin comprised less than 5% of ovarian carotenoids. Three glycolic isomers of crustaxanthin were detected (3,4,3',4'-di-cis-:3,4-cis-3',4'-trans-:3,4,3',4'-di-trans-glycolic isomer ratio 2.6:3.1:1) in the ovaries. Sex and maturity status had no apparent effect on the relative composition of skin carotenoids. The skin carotenoids consisted mainly of diesters (82-87% of total carotenoids) and monoesters (7-13% of total carotenoids). Saponification revealed that astaxanthin comprised 85% and idoxanthin 10% of total carotenoids, and minor amounts of tunaxanthin-, lutein-, and zeaxanthin-like metabolites were also present. Maturity status seems to be more important than sex in determining the relative carotenoid composition of the tissues of Arctic charr, with astaxanthin and its metabolites being selectively accumulated in different tissues.