Exogenous Hormone Administration Research Articles

Repetitive Maturation of Oocytes From Non-Stimulated Xenografted Ovarian Tissue From a Prepubertal Patient Indicating the Independence of Human Ovarian Tissue.

Introduction Modern anti-cancer strategies have distinctly increased survival rates; nevertheless, often accompanied by sterility. Currently, the only option for preserving fertility in prepubertal females is to cryopreserve ovarian tissue and re-transplant frozen-thawed tissue to restore fertility after treatment. Our aim was to report the occurrence of repetitive antral follicle formation and oocyte maturation in a prepubescent ovarian tissue xenograft without exogenous hormone stimulation. Material and Methods Frozen-thawed ovarian tissue from a 6-year-old patient suffering from nephroblastoma was xenotransplanted in oophorectomized severe combined immunodeficiency (SCID) mice to evaluate follicle development. Ergebnisse Repetitive follicle development to the antral stage occurred in the same xenograft of prepubertal ovarian tissue without exogenous hormone administration; 37 days after retrieving a maturing oocyte (this first retrieval has been previously published), another, completely mature oocyte was harvested from the xenograft. Subsequent histological evaluation of the grafted tissue showed primordial follicles, nearly all stages of developing follicles, as well as large atretic ones. Many clusters with dormant primordial follicles were also present. Conclusion Xenotransplanted prepubertal ovarian tissue has the potential for repetitive oocyte retrieval cycles without administering exogenous hormones. The results indicate that the human ovarian tissue might be able to synchronize the hypothalamus-hypophysis-axes of the mouse to the physiological human cycle; this should be investigated in future studies.

Transcriptomic signature of the follicular somatic compartment surrounding an oocyte with high developmental competence

During antral folliculogenesis, developmental competence of prospective oocytes is regulated in large part by the follicular somatic component to prepare the oocyte for the final stage of maturation and subsequent embryo development. The underlying molecular mechanisms are poorly understood. Oocytes reaching the advanced stage of follicular growth by administration of exogenous follicle-stimulating hormone (FSH) possess higher developmental competence than oocytes in FSH-untreated smaller follicles. In this study, the transcriptomic profile of the cumulus cells from cows receiving FSH administration (FSH-priming) was compared, as a model of high oocyte competence, with that from untreated donor cows (control). Ingenuity Pathway Analysis showed that cumulus cells receiving FSH-priming were rich in down-regulated transcripts associated with cell movement and migration, including the extracellular matrix-related transcripts, probably preventing the disruption of cell-to-cell contacts. Interestingly, the transcriptomic profile of up-regulated genes in the control group was similar to that of granulosa cells from atretic follicles. Interferon regulatory factor 7 was activated as the key upstream regulator of FSH-priming. Thus, acquisition of developmental competence by oocytes can be ensured by the integrity of cumulus cells involved in cell-to-cell communication and cell survival, which may help achieve enhanced oocyte-somatic cell coupling.

Hormonal Cycle and Contraceptive Effects on Amygdala and Salience Resting-State Networks in Women with Previous Affective Side Effects on the Pill.

The mechanisms linking ovarian hormones to negative affect are poorly characterized, but important clues may come from the examination of the brain's intrinsic organization. Here, we studied the effects of both the menstrual cycle and oral contraceptives (OCs) on amygdala and salience network resting-state functional connectivity using a double-blind, randomized, and placebo-controlled design. Hormone levels, depressive symptoms, and resting-state functional connectivity were measured in 35 healthy women (24.9±4.2 years) who had previously experienced OC-related negative affect. All participants were examined in the follicular phase of a baseline cycle and in the third week of the subsequent cycle during treatment with either a combined OC (30 μg ethinyl estradiol/0.15 mg levonorgestrel) or placebo. The latter time point targeted the midluteal phase in placebo users and steady-state ethinyl estradiol and levonorgestrel concentrations in OC users. Amygdala and salience network connectivity generally increased with both higher endogenous and synthetic hormone levels, although amygdala-parietal cortical connectivity decreased in OC users. When in the luteal phase, the naturally cycling placebo users demonstrated higher connectivity in both networks compared with the women receiving OCs. Our results support a causal link between the exogenous administration of synthetic hormones and amygdala and salience network connectivity. Furthermore, they suggest a similar, potentially stronger, association between the natural hormonal variations across the menstrual cycle and intrinsic network connectivity.

Cardiovascular Disease Among Transgender Adults Receiving Hormone Therapy: A Narrative Review.

Recent reports estimate that 0.6% of adults in the United States, or approximately 1.4 million persons, identify as transgender. Despite gains in rights and media attention, the reality is that transgender persons experience health disparities, and a dearth of research and evidence-based guidelines remains regarding their specific health needs. The lack of research to characterize cardiovascular disease (CVD) and CVD risk factors in transgender populations receiving cross-sex hormone therapy (CSHT) limits appropriate primary and specialty care. As with hormone therapy in cisgender persons (that is, those whose sex assigned at birth aligns with their gender identity), existing research in transgender populations suggests that CVD risk factors are altered by CSHT. Currently, systemic hormone replacement for cisgender adults requires a nuanced discussion based on baseline risk factors and age of administration of exogenous hormones because of concern regarding an increased risk for myocardial infarction and stroke. For transgender adults, CSHT has been associated with the potential for worsening CVD risk factors (such as blood pressure elevation, insulin resistance, and lipid derangements), although these changes have not been associated with increases in morbidity or mortality in transgender men receiving CSHT. For transgender women, CSHT has known thromboembolic risk, and lower-dose transdermal estrogen formulations are preferred over high-dose oral formulations. In addition, many studies of transgender adults focus predominantly on younger persons, limiting the generalizability of CSHT in older transgender adults. The lack of randomized controlled trials comparing various routes and formulations of CSHT, as well as the paucity of prospective cohort studies, limits knowledge of any associations between CSHT and CVD.

Improvements in oocyte competence in superovulated mice following treatment with cilostazol: Ovulation of immature oocytes with high developmental rates

Exogenous administration of superovulatory hormones negatively affects oocyte competence in mammals. Phosphodiesterase 3A inhibitors were found to improve competence of oocytes matured in vitro in several species, including humans. This study was therefore designed to define oocyte maturation synchronization and competence, in vivo, using superovulated mice treated with cilostazol, a selective phosphodiesterase 3A inhibitor. Swiss Webster mice were superovulated and treated orally with 7.5mg cilostazol once or twice to result in ovulation of immature oocytes at the metaphase I (MI) or germinal vesicle (GV) stage, respectively. Control immature oocytes were recovered from preovulatory follicles of superovulated mice not treated with cilostazol. Treated GV oocytes had significantly higher rates of synchronized and advanced chromatin configuration and cortical granule distribution than did control GV oocytes. Treated GV oocytes had a moderate increase in cAMP levels and consequently higher rates of meiotic maturation, IVF, and blastocyst formation than did control GV oocytes (P<0.0001). Treated MI oocytes had higher rates of normal spindles and chromosomes aligned at the metaphase plate than did control MI oocytes (P<0.003). Treated mice ovulating MI oocytes produced litter sizes larger than those observed in control mice ovulating mature oocytes (P<0.002). This study reveals that synchronization of oocyte maturation in superovulated mice improves oocyte development and competence. The capability of cilostazol, a clinically approved medication, to improve mouse oocyte competence suggests the potential benefit of including this compound in ovarian hyperstimulation programs to improve in vitro fertilization outcomes in infertile women.

Safety Profile of Finasteride: Distribution of Adverse Effects According to Structural and Informational Dichotomies of the Mind/Brain.

Finasteride is currently used extensively for male androgenic alopecia and benign prostatic hyperplasia; however, some adverse effects are severe and even persistent after treatment cessation, the so-called 'post-finasteride syndrome'. The following most severe adverse effects-sexual dysfunction and depression-often occur together and may potentiate one other, a fact that could explain (at least in part) the magnitude and persistence of finasteride adverse effects. This paper presents the pharmacological action of finasteride and the corresponding adverse effects, the biological base explaining the occurrence, persistence and distribution of these adverse effects, and a possible therapeutic solution for post-finasteride syndrome. The distribution of finasteride adverse effects is presented within a comprehensive and modern neuro-endocrine perspective related to structural and informational dichotomies of the brain. Understanding the variation of finasteride side effects among different populations would be necessary not only to delineate the safety profile of finasteride for different subgroups of men (a subject may or may not be affected by a certain anti-hormonal compound dependent on the individual neuro-endocrine profile), but also as a possible premise for a therapeutic approach of finasteride adverse effects. Such therapeutic approach should include administration of exogenous hormones, which are deficient in men with post-finasteride syndrome, namely dihydrotestosterone (in right-handed men) or progesterone/dihydroprogesterone (in left-handed subjects).

Plasticity in Uterine Innervation: State of the Art.

Early studies often claimed that autonomic nerves were unimportant for uterine function, since denervation of the uterus had little effects on reproductive success. In 1979, Thorbert wrote, "It seems unlikely that Nature has equipped the uterus with a complex innervation merely as a structural ornament. Our ignorance in this area may be rather due to defects in methods of study". Investigations carried out over the last four decades proved that Thorbert's words were correct, because it is now clear that autonomic and sensory nerves regulate many critical uterine functions. However, the most remarkable aspect of uterine innervation is its capacity to change in response to physiological fluctuations in levels of sex hormones, as those accompanying pregnancy, the sex cycle and puberty. The present review provides an overview about how sex hormones influence uterine innervation. Data are presented about how this physiological plasticity is mimicked by exogenous administration of sex hormones, particularly estrogen. We will review recent developments illustrating the complex multifactorial mechanisms regulating uterine neural plasticity and the nature of molecular signals involved. Finally, we will go through recent findings pointing to the relevance of uterine innervation in gynecological diseases leading to pain and infertility.

A Simple Experiment Demonstrating Hormonal Control of Cutaneous Drinking in Toads

Simple teaching experiments demonstrating endocrinological concepts are difficult to come by. I discuss a simple experiment demonstrating control of cutaneous drinking by the hormone angiotensin II in terrestrial toads, designed after methods published in the primary literature and presented herein to make this exercise more widely accessible to ABT readers. This experiment is notable in that it (1) permits students to quantify both a physiological and a behavioral response to exogenous hormone administration; (2) can be implemented in relatively small class sizes; (3) does not require animal euthanasia; and (4) can be accomplished in one class period. Furthermore, data collection can be easily carried out by students using common laboratory supplies, and analysis and interpretation of the collected data are straightforward. Finally, in demonstrating the function of the highly conserved renin-angiotensin-aldosterone system, this hands-on experiment has obvious clinical connections relevant to human medicine (e.g., blood-pressure regulation and treatment of hypertension).

Influence of SULT1A1 genetic variation on age at menopause, estrogen levels, and response to hormone therapy in recently postmenopausal white women.

Objective:Onset and symptoms of menopause, and response to hormone therapy (HT) show large interindividual variability. SULT1A1 encodes for a highly expressed enzyme that metabolizes estrogens. We evaluated the relationship between genetic variation in SULT1A1, menopause age, symptoms, and response to HT.Methods:Women enrolled in the Kronos Early Estrogen Prevention Study at Mayo Clinic were randomized to 48 months of treatment with oral conjugated equine estrogen (n = 34), transdermal 17β-estradiol (E2) (n = 33), or placebo (n = 35). Linear regression models and ANOVA were used to test for association of SULT1A1 copy number, rs3760091, rs750155, and rs9282861 (SULT1A1∗2), with age at menopause and symptoms, levels of estrogens (estrone [E1], estrone sulfate [E1S], E2, and estradiol sulfate [E2S]), before and after HT.Results:SULT1A1 gene copy number affected the minor allele frequency for each single nucleotide polymorphisms tested. Before administration of exogenous hormones, increasing number of G alleles at rs9282861 was associated with earlier age at menopause (P = 0.014), lower frequency of night sweats (P = 0.009), and less severe insomnia (P = 0.046). After 48 months of treatment, SULT1A1 genotype was not associated with the presence of menopausal symptoms. In women randomized to oral conjugated equine estrogen, increasing number of the A allele at rs750155 was associated with lower E1S and E2S (P = 0.004 and 0.017), whereas increasing number of the C allele at rs3760091 was associated with lower E2S/E2 (P = 0.044).Conclusions:Interindividual variability in onset of menopause and symptoms before initiation of HT is explained in part by genetic variation in SULT1A1 and may represent a step toward individualizing HT treatment decisions.

Preliminary Remarks in Hormonal Treatments Effects on Reproduction Period in Cows

The early resumption of estrous cycles following calving is important for high reproductive efficiency and for the cows which haven’t been observed in estrus during the first 60 days after calving have a significantly higher risk of being culled than cows that have displayed estrus (Opsomer et al., 2000). The aim of this study was to determine the effect of hormonal treatment on reproduction period in cows, but also to establish if there is any significant difference in some reproductive parameters between cows treated with hormonal medication and cows which resumed ovarian cyclicity before 60 days postpartum. This study was performed in a dairy cows farm in North-Eastern Moldavia, over a period of 2 consecutive years, on Romanian Black Spotted cows in order to determine hormonal treatments influence on reproduction period. Hormonal treatments used for the above mentioned diseases were represented by luteolytic agent prostaglandin F2I±, one of its potent analogues (Proliz, Biotur, Romania) and by administration of exogenous gonadotrophin releasing hormone (Receptal, Intervet, Romania). We noticed that average reproduction period (52.1 days) and the other breeding intervals that were taken under study (over a two years period), presented different values for cows that have been under hormonal medication treatment, compared to those that resumed ovarian cyclicity before 60 days postpartum (52.7 days). Thus, this preliminary study supports the development of a more detailed study on several dairy cows farms in order to investigate the answer of different types of hormonal treatments against persistent corpus luteum and cystic ovarian disease.

Heat stress and ACTH administration on cortisol and insulin-like growth factor I (IGF-I) levels in lactating Holstein cows

ABSTRACTPhysiological and productive responses were studied in five Holstein cows in thermal comfort (T1), stress by exogenous adrenocorticotropic hormone (ACTH) administration (T2) and heat stress (T3) to compare acute and punctual stress (ACTH) and prolonged stress (heat stress). During T1 and T2, cows were housed in a climatic-free stall barn. In T3, the animals were kept in a climatic room (air temperature of 37°C from 08:00 to 13:00 h, and of 26°C from 14:00 to 07:00 h) for 7 days. Milk yield, rectal temperature (RT), respiratory rate (RR) and blood samples were obtained before, during and after all treatments. In T1 at 08:00 h, RT and RR were below the upper critical limit. Simultaneously, cortisol and insulin growth-factor I (IGF-I) were within the normal limits. After ACTH administration (T2), cortisol significantly increased, reaching maximum levels at 60 min and returning to basal levels at 300 min. However, IGF-I was not affected. During T3, Holstein cows did not effectively dissipate their body temperature and RT, RR and cortisol significantly increased. There was a 26.6% reduction in milk production after heat stress (P < .05). Prolonged heat stress was more stressful and cows had higher levels of CORT in T3 than in T2 even before the increase in body temperature. Although the total amount of cortisol and IGF-I presented a negative and significant Pearson correlation (r = −0.79), IGF-I was not significantly influenced by heat stress or ACTH administration, and the relationship between IGF-I and heat stress remains controversial.

Administration of Exogenous Growth Hormone Is Associated with Changes in Plasma and Intracellular Mammary Amino Acid Profiles and Abundance of the Mammary Gland Amino Acid Transporter SLC3A2 in Mid-Lactation Dairy Cows

The objectives of this study were to (1) identify changes in plasma and mammary intracellular amino acid (AA) profiles in dairy cows treated with growth hormone (GH), and (2) evaluate the expression of mammary gland genes involved in the transport of AA identified in (1). Eight non-pregnant (n = 4 per group) lactating dairy cows were treated with a single subcutaneous injection of either a slow-release formulation of commercially available GH (Lactotropin 500 mg) or physiological saline solution. Six days after treatment, cows were milked and blood collected from the jugular vein for the analysis of free AA in the plasma. Cows were euthanized and mammary tissue harvested. Treatment with GH increased milk, protein, fat and lactose yields, with no effect on dry matter intake. Plasma concentrations of lysine and group I AA decreased significantly, and arginine, methionine, tyrosine and arginine-family AA tended to decrease in GH-treated cows. Concentrations of intracellular glycine, serine and glutamate increased significantly, with a trend for decreased arginine observed in the mammary gland of GH-treated cows. A trend for increased concentrations of intracellular total AA, NEAA and arginine-family AA were observed in the mammary gland of GH-treated cows. Variance in the concentration of plasma methionine, tyrosine, valine, alanine, ornithine, BCAA, EAA was significantly different between treatments. Variance in the concentration of intracellular lysine, valine, glutamine, EAA and group II was significantly different between treatments. AA changes were associated with increased mRNA abundance of the mammary gland AA transporter SLC3A2. We propose that these changes occur to support increased milk protein and fatty acid production in the mammary gland of GH-treated cows via potential mTOR pathway signaling.

Peritoneal Pigmentation in Purebred and Hybrid River Herring

AbstractRiver herring (Alewives Alosa pseudoharengus and Blueback Herring A. aestivalis [bluebacks]) are congeneric, anadromous clupeid fishes that hybridize in areas of sympatry. Peritoneal pigmentation is the most diagnostic characteristic used to distinguish the species, but pigmentation has not been examined in hybrids. We developed a molecular‐based assay to distinguish purebred river herring species from F1 hybrids and compared the peritoneal pigmentation among captive‐raised purebred and hybrid individuals. Both wild‐caught Alewife and blueback females tank‐spawned with conspecific and congeneric males, but Alewives required exogenous hormone administration. Larvae of both species and hybrids were raised for ∼290 d posthatch, and peritoneal pigmentation was quantified. A nuclear gene (rag2) restriction fragment length polymorphism assay was used for species and hybrid identification. The peritoneal pigmentation was significantly darker in hatchery‐spawned bluebacks than in Alewives, and hybrids exhibited consistent, intermediate expression. Adult individuals collected from the wild, however, exhibited darker (Alewives) or more variable (bluebacks) peritoneal coloration than their respective, captive‐reared juveniles. These results indicated that peritoneal pigmentation alone is insufficient for diagnostic river herring species identification and should be coupled with genetic assays.

Spawning, Larviculture, and Salinity Tolerance of Alewives and Blueback Herring in Captivity

AbstractPrecipitous declines in wild populations of river herring species (Alewives Alosa pseudoharengus and Blueback Herring A. aestivalis) have led to increased interest in stock enhancement efforts. Additionally, their popularity as a baitfish among recreational anglers has generated interest in commercial production of these species for marine baitfish markets. The objective of this investigation was to elucidate practical culture protocols for captive propagation of these species for commercial and restoration purposes. Wild Blueback Herring, captured during their annual spawning migration, spawned in tanks volitionally, while Alewives required exogenous hormone administration. Larvae of both species were successfully raised through metamorphosis using a feeding regime comprised of enriched rotifers followed by Artemia nauplii and a commercially available diet. Survival of early larvae acclimated to salinities ranging from 5‰ to 15‰ was high for both species (&gt;94.0%) while that for older larvae acclimated to 15, 20, and 30‰ ranged from 64.7% to 95.3%. Juveniles raised at varying salinities (0–30‰) exhibited high survival (95.6–100.0%) and excellent feed conversion ratios (≤1.31) in all treatments. In acute salinity transfer experiments, high survival was observed when fish of both species (233–275 d posthatch) were transferred from low to high salinities, but low survival (10.0% and 3.3%) was observed in Alewives transferred from 15‰ or 30‰ to freshwater (0‰). A nodular fibrotic growth was found on 3.7% and 10.1% of the cultured Alewives and Blueback Herring (≥231 d posthatch), respectively, that likely followed tissue trauma and ulceration. The results of these studies provide a framework for river herring culture in recirculating systems.

Growth hormone ameliorates adipose dysfunction during oxidative stress and inflammation and improves glucose tolerance in obese mice.

Patients with adult growth hormone deficiency exhibit visceral fat accumulation, which gives rise to a cluster of metabolic disorders such as impaired glucose tolerance and dyslipidemia. Plasma growth hormone levels are lower in obese patients with metabolic syndrome than in healthy subjects. Here we examined the hypothesis that exogenous growth hormone administration regulates function of adipose tissue to improve glucose tolerance in diet-induced obese mice. Twelve-week-old obese male C57BL/6 J mice received bovine growth hormone daily for 6 weeks. In epididymal fat, growth hormone treatment antagonized diet-induced changes in the gene expression of adiponectin, leptin, and monocyte chemoattractant protein-1, and significantly increased the gene expression of interleukin-10 and CD206. Growth hormone also suppressed the accumulation of oxidative stress marker, thiobarbituric acid-reactive substances, in the epididymal fat and enhanced the gene expression of anti-oxidant enzymes. Moreover, growth hormone significantly restored glucose tolerance in obese mice. In cultured 3T3-L1 adipocytes, growth hormone prevented the decline in adiponectin gene expression in the presence of hydrogen peroxide. These results suggest that growth hormone administration ameliorates glucose intolerance in obese mice presumably by decreasing adipose mass, oxidative stress, and chronic inflammation in the visceral fat.

A functional neuroimaging review of obesity, appetitive hormones and ingestive behavior

Adequate energy intake is vital for the survival of humans and is regulated by complex homeostatic and hedonic mechanisms. Supported by functional MRI (fMRI) studies that consistently demonstrate differences in brain response as a function of weight status during exposure to appetizing food stimuli, it has been posited that hedonically driven food intake contributes to weight gain and obesity maintenance. These food reward theories of obesity are reliant on the notion that the aberrant brain response to food stimuli relates directly to ingestive behavior, specifically, excess food intake. Importantly, functioning of homeostatic neuroendocrine regulators of food intake, such as leptin and ghrelin, are impacted by weight status. Thus, data from studies that evaluate the effect on weight status on brain response to food may be a result of differences in neuroendocrine functioning and/or behavior. In the present review, we examine the influence of weight and weight change, exogenous administration of appetitive hormones, and ingestive behavior on BOLD response to food stimuli.

Acute effects of exogenous hormone administration on postprandial acylation stimulating protein levels in ovariectomized rats after a fat load.

Background. ASP, a potent lipogenic factor, was linked to female fat metabolism in association studies. Aim. To investigate acute effects of sex hormone treatment on postprandial ASP levels in vivo. Methods. 24 female rats were randomly divided into 4 groups including controls. The rats were ovariectomized and injected with progesterone, estrogen, or testosterone. An hour later, olive oil was administered orally. Plasma ASP and triglycerides were measured at several postprandial time points. Area under the curve (TG-AUC) represented TG clearance. Results. Only the progesterone treated group had a significant postprandial ASP increase at two hours compared to basal levels (439.8 ± 62.4 versus 253.4 ± 59.03 μg/mL, P = 0.04). Interestingly, increased ASP levels coordinated negatively with corresponding TG levels and TG-AUC postprandially, mostly evident in the opposite effects in the progesterone and testosterone treated groups. ASP levels increased 3-fold in the progesterone versus testosterone treated groups, whereas TG-AUC was significantly lower. Conclusion. These findings suggest that progesterone enhances ASP production and TG clearance simultaneously, supporting the notion of a stimulatory role for progesterone on ASP-mediated TG clearance. This is the first functional study demonstrating a cause-effect relationship between hormone treatment and ASP levels in vivo and may contribute to understanding the mechanism of progesterone function as a female lipogenic hormone.

026 Cryoconservation: Successful sperm cryopreservation and develop-mental outcomes using endangered North American amphibians

In response to the dramatic global decline of amphibian species, captive assurance colonies are being established to safeguard genetic diversity; however, many of these founder populations fail to reproduce. Therefore, assisted reproductive technologies such as gamete cryopreservation and artificial fertilisation are valuable conservation tools in the genetic management and breeding of these non-reproducing populations. The following study aimed to develop a successful sperm cryopreservation protocol for two endangered amphibian species maintained in captivity: the threatened boreal toad (Anaxyrus boreas boreas) and the critically endangered Mississippi gopher frog (Lithobates sevosa). Spermiation was induced by exogenous hormone administration of human chorionic gonadotropin at 10IU/g for A. b. boreas and by a cocktail of 500 IU hCG and 15 μg luteinizing hormone-releasing hormone for L. sevosa. Fresh sperm quality was assessed using the following parameters: (1) sperm concentration (2) percentage motile sperm, and (3) percentage sperm moving progressively forward. Sperm samples were subsequently extended 1:1 in chilled cryoprotectant containing 10% (v/v) N-N-dimethylformamide and 10% (w/v) trehalose. The chilled sperm suspensions were held at 4 °C for an acclimation period of 10 min before being loaded into 0.25 mL plastic freezing straws and frozen in a step-wise slow-rate freezing process. Straws were thawed in a 40 °C water bath before a 1:10 dilution with aged tap water to activate the sperm for re-evaluation. Exogenous hormone induction stimulated spermiation in A. b. boreas and L. sevosa, producing mean fresh sperm concentrations of 4.6 × 106/mL and 2.4 × 106/mL respectively, with high rates of motility for both A. b. boreas (86 ± 4%) and L. sevosa (92 ± 2%) (mean ± SE). Upon activation, motility recovery from cryopreserved sperm suspensions was high for A. b. boreas (62 ± 2%) and L. sevosa (70 ± 3%) and sperm forward progression was maintained for both species (57 ± 3% and 29 ± 6%, for A. b. boreas and L. sevosa, respectively). Furthermore, frozen-thawed spermatozoa were used for fertilisation trials and developmental stages analysis. Preliminary investigations using cryopreserved L. sevosa sperm indicated that 14% of fertilised oocytes developed to 2-cell stage embryos with 6% continuing to tadpole stage. The results of this study demonstrate that sperm from both A. b. boreas and L. sevosa can be successfully cryopreserved and maintain high rates of sperm motility and forward progressive movement recovery. Additionally, fertilisation can be achieved in the critically endangered Mississippi gopher frog with subsequent tadpole production. The ability to successfully cryopreserve sperm from endangered amphibian species has enormous potential in augmenting declining populations by facilitating gene flow, both between breeding facilities and between in situ and ex situ populations, without removing source animals. Moreover, this methodology may be directly applicable to a wide range of amphibian taxa, affording a viable option for securing the remaining genetic diversity of endangered species in a global genetic resource bank. Source of funding: Institute of Museum and Library Services. Conflict of interest: None declared. cjl224@msstate.edu

Temperature dependent action of growth hormone on somatic growth and testicular activities of the catfish, Clarias batrachus

Effects of growth hormone on somatic growth and testicular activities were studied during late quiescence and early recrudescence phases of the reproductive cycle of the catfish, Clarias batrachus. The administration of exogenous growth hormone (GH) during the late quiescence phase (December–January; ambient water temperature-15.2±1°C) did not influence the somatic growth as well as the testicular activity, as no change in body weight, testis weight, plasma level of insulin-like growth factor I (IGF-I) and testicular morphology was detected following GH treatment, though the plasma testosterone was marginally increased. While during the early recrudescence phase (March–April; ambient water temperature-28.1±2°C), GH treatment promoted the production of insulin like growth factor-I and testicular steroidogenic activity in a dose dependent manner, as was evident from the significant increase in the circulating levels of testosterone and estradiol-17β. GH treatment also increased body weight, testicular weight and gonadosomatic index, suggesting its involvement in testicular development. The GH treatment promoted spermatogonial proliferation and accelerated the spermatogenic process in the present catfish. These results, thus, suggest that GH influences the somatic growth and testicular activities depending on the temperature of the rearing water; warmer temperature and longer photoperiod promote testicular steroidogenic and spermatogenic activities in fish. This study has immense practical use in fisheries science.

The inflamed axis: The interaction between stress, hormones, and the expression of inflammatory-related genes within key structures comprising the hypothalamic–pituitary–adrenal axis

Acute stress increases the expression of cytokines and other inflammatory-related factors in the CNS, plasma, and endocrine glands, and activation of inflammatory signaling pathways within the hypothalamic–pituitary–adrenal (HPA) axis may play a key role in later stress sensitization. In addition to providing a summary of stress effects on neuroimmune changes within the CNS, we present a series of experiments that characterize stress effects on members of the interleukin-1β (IL-1) super-family and other inflammatory-related genes in key structures comprising the HPA axis (PVN, pituitary and adrenal glands), followed by a series of experiments examining the impact of exogenous hormone administration (CRH and ACTH) and dexamethasone on the expression of inflammatory-related genes in adult male Sprague–Dawley rats. The results demonstrated robust, time-dependent, and asynchronous expression patterns for IL-1 and IL-1R2 in the PVN, with substantial increases in IL-6 and COX-2 in the adrenal glands emerging as key findings. The effects of exogenous CRH and ACTH were predominantly isolated within the adrenals. Finally, pretreatment with dexamethasone severely blunted neuroimmune changes in the adrenal glands, but not in the PVN. These findings provide novel insight into the relationship between stress, the expression of inflammatory signaling factors within key structures comprising the HPA axis, and their interaction with HPA hormones, and provide a foundation for better understanding the role of cytokines as modulators of hypothalamic, pituitary and adrenal sensitivity.