@article{deck_mankiewicz_borski_2022, title={Evidence for a leptin-insulin axis in a fish, the tilapia (Oreochromis mossambicus)}, volume={253}, ISSN={["1479-6805"]}, DOI={10.1530/JOE-21-0139}, abstractNote={Leptin, insulin, and glucagon are involved in regulating glycaemia in vertebrates and play a role in the progression of obesity and type 2 diabetes. While mammals possess an ‘adipoinsular axis’ whereby insulin stimulates leptin release from adipocytes and leptin in turn feeds back on the pancreas to inhibit further insulin secretion, evidence of such an axis in non-mammalian vertebrates is unknown. We investigated the interactions between these glycaemic hormones and provide evidence for a leptin–insulin axis in a teleost fish, the tilapia. In the first study, we exposed hepatocytes to various concentrations of either insulin or glucagon to determine effects on leptin a (lepa) and then examined this in vivo with i.p. injections of both hormones. We also exposed isolated Brockmann bodies (pancreatic islets) to recombinant tilapia leptin A (rtLepA) and again followed this up with an i.p. injection to examine changes in insulin a and glucagon b. We found that glucagon increases lepa in vitroand in vivo, with the latter being 18-fold higher than saline-injected controls; however, the effects of rtLepA on glub were more variable. Insulin increased lepa by 2.5-fold in vitro and 70-fold in vivo, while rtLepA decreased insa at basal and increased it at high glucose concentrations. These data indicate that a leptin–insulin axis may be conserved among vertebrates and is thus essential for regulating nutrient balance but that the relationship is likely much more dynamic in teleosts as glycaemia is not as tightly regulated as it is in mammals.}, number={1}, journal={JOURNAL OF ENDOCRINOLOGY}, author={Deck, Courtney A. and Mankiewicz, Jamie L. and Borski, Russell J.}, year={2022}, month={Apr}, pages={13–25} }
 @article{mankiewicz_deck_taylor_douros_borski_2021, title={Epinephrine and glucose regulation of leptin synthesis and secretion in a teleost fish, the tilapia (Oreochromis mossambicus)}, volume={302}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2020.113669}, abstractNote={Acute stress is regulated through the sympathetic adrenergic axis where catecholamines mobilize energy stores including carbohydrates as a principal element of the endocrine stress response. Leptin is a cytokine critical for regulating energy expenditure in vertebrates and is stimulated by various stressors in fish such as fasting, hyperosmotic challenge, and hypoxia. However, little is known about the regulatory interactions between leptin and the endocrine stress axis in fishes and other ectothermic vertebrates. We evaluated the actions of epinephrine and glucose in regulating leptin A (LepA) in vivo and in vitro in tilapia. Using hepatocyte incubations and a homologous LepA ELISA, we show that LepA synthesis and secretion decline as ambient glucose levels increase (10–25 mM). By contrast, bolus glucose administration in tilapia increases lepa mRNA levels 14-fold at 6 h, suggesting systemic factors regulated by glucose may counteract the direct inhibitory effects of glucose on hepatic lepa mRNA observed in vitro. Epinephrine stimulated glucose and LepA secretion from hepatocytes in a dose-dependent fashion within 15 min but had little effect on lepa mRNA levels. An in vivo injection of epinephrine into tilapia stimulated a rapid rise in blood glucose which was followed by a 4-fold increase in hepatic lepa mRNA levels at 2.5 and 6 h. Plasma LepA was also elevated by 6 h relative to controls. Recombinant tilapia LepA administration in vivo did not have any significant effect on plasma epinephrine levels. The results of this study demonstrate LepA is negatively regulated by rises in extracellular glucose at the level of the hepatocyte but stimulated by hyperglycemia in vivo. Further, epinephrine increases LepA. This, along with previous work demonstrating a hyperglycemic and glycogenolytic effect of LepA in tilapia, suggests that epinephrine may stimulate leptin secretion to augment and fine tune glucose mobilization and homeostasis as part of the integrated, adaptive stress response.}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Mankiewicz, Jamie L. and Deck, Courtney A. and Taylor, Jordan D. and Douros, Jonathan D. and Borski, Russell J.}, year={2021}, month={Feb} }
 @article{johnstone_honeycutt_deck_borski_2019, title={Nongenomic glucocorticoid effects and their mechanisms of action in vertebrates}, volume={346}, ISSN={["1937-6448"]}, DOI={10.1016/bs.ircmb.2019.03.004}, abstractNote={Glucocorticoids (GC) act on multiple organ systems to regulate a variety of physiological processes in vertebrates. Due to their immunosuppressive and anti-inflammatory actions, glucocorticoids are an attractive target for pharmaceutical development. Accordingly, they are one of the most widely prescribed classes of therapeutics. Through the classical mechanism of steroid action, glucocorticoids are thought to mainly affect gene transcription, both in a stimulatory and suppressive fashion, regulating de novo protein synthesis that subsequently leads to the physiological response. However, over the past three decades multiple lines of evidence demonstrate that glucocorticoids may work through rapid, nonclassical mechanisms that do not require alterations in gene transcription or translation. This review assimilates evidence across the vertebrate taxa on the diversity of nongenomic actions of glucocorticoids and the membrane-associated cellular mechanisms that may underlie rapid glucocorticoid responses to include potential binding sites characterized to date.}, journal={INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY, VOL 346}, author={Johnstone, William M., III and Honeycutt, Jamie L. and Deck, Courtney A. and Borski, Russell J.}, year={2019}, pages={51–96} }
 @book{sex control in aquaculture, vols i and ii_2019, ISBN={["978-1-119-12726-0"]}, DOI={10.1002/9781119127291}, journal={SEX CONTROL IN AQUACULTURE, VOLS I AND II}, year={2019}, pages={1–846} }
 @article{honeycutt_deck_miller_severance_atkins_luckenbach_buckel_daniels_rice_borski_et al._2019, title={Warmer waters masculinize wild populations of a fish with temperature-dependent sex determination}, volume={9}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/s41598-019-42944-x}, DOI={10.1038/s41598-019-42944-x}, abstractNote={Abstract}, number={1}, journal={Scientific Reports}, publisher={Springer Nature}, author={Honeycutt, J. L. and Deck, C. A. and Miller, S. C. and Severance, M. E. and Atkins, E. B. and Luckenbach, J. A. and Buckel, J. A. and Daniels, H. V. and Rice, J. A. and Borski, R. J. and et al.}, year={2019}, month={Apr} }
 @article{douros_baltzegar_mankiewicz_taylor_yamaguchi_lerner_seale_grau_breves_borski_2017, title={Control of leptin by metabolic state and its regulatory interactions with pituitary growth hormone and hepatic growth hormone receptors and insulin like growth factors in the tilapia (Oreochromis mossambicus)}, volume={240}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2016.07.017}, abstractNote={Leptin is an important cytokine for regulating energy homeostasis, however, relatively little is known about its function and control in teleost fishes or other ectotherms, particularly with regard to interactions with the growth hormone (GH)/insulin-like growth factors (IGFs) growth regulatory axis. Here we assessed the regulation of LepA, the dominant paralog in tilapia (Oreochromis mossambicus) and other teleosts under altered nutritional state, and evaluated how LepA might alter pituitary growth hormone (GH) and hepatic insulin-like growth factors (IGFs) that are known to be disparately regulated by metabolic state. Circulating LepA, and lepa and lepr gene expression increased after 3-weeks fasting and declined to control levels 10days following refeeding. This pattern of leptin regulation by metabolic state is similar to that previously observed for pituitary GH and opposite that of hepatic GHR and/or IGF dynamics in tilapia and other fishes. We therefore evaluated if LepA might differentially regulate pituitary GH, and hepatic GH receptors (GHRs) and IGFs. Recombinant tilapia LepA (rtLepA) increased hepatic gene expression of igf-1, igf-2, ghr-1, and ghr-2 from isolated hepatocytes following 24h incubation. Intraperitoneal rtLepA injection, on the other hand, stimulated hepatic igf-1, but had little effect on hepatic igf-2, ghr1, or ghr2 mRNA abundance. LepA suppressed GH accumulation and gh mRNA in pituitaries in vitro, but had no effect on GH release. We next sought to test if abolition of pituitary GH via hypophysectomy (Hx) affects the expression of hepatic lepa and lepr. Hypophysectomy significantly increases hepatic lepa mRNA abundance, while GH replacement in Hx fish restores lepa mRNA levels to that of sham controls. Leptin receptor (lepr) mRNA was unchanged by Hx. In in vitro hepatocyte incubations, GH inhibits lepa and lepr mRNA expression at low concentrations, while higher concentration stimulates lepa expression. Taken together, these findings indicate LepA gene expression and secretion increases with fasting, consistent with the hormones function in promoting energy expenditure during catabolic stress. It would also appear that LepA might play an important role in stimulating GHR and IGFs to potentially spare declines in these factors during catabolism. Evidence also suggests for the first time in teleosts that GH may exert important regulatory effects on hepatic LepA production, insofar as physiological levels (0.05-1 nM) suppresse lepa mRNA accumulation. Leptin A, may in turn exert negative feedback effects on basal GH mRNA abundance, but not secretion.}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Douros, Jonathan D. and Baltzegar, David A. and Mankiewicz, Jamie and Taylor, Jordan and Yamaguchi, Yoko and Lerner, Darren T. and Seale, Andre P. and Grau, E. Gordon and Breves, Jason P. and Borski, Russell J.}, year={2017}, month={Jan}, pages={227–237} }
 @article{marjoram_alvers_deerhake_bagwell_mankiewicz_cocchiaro_beerman_willer_sumigray_katsanis_et al._2015, title={Epigenetic control of intestinal barrier function and inflammation in zebrafish}, volume={112}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.1424089112}, abstractNote={Significance}, number={9}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Marjoram, Lindsay and Alvers, Ashley and Deerhake, M. Elizabeth and Bagwell, Jennifer and Mankiewicz, Jamie and Cocchiaro, Jordan L. and Beerman, Rebecca W. and Willer, Jason and Sumigray, Kaelyn D. and Katsanis, Nicholas and et al.}, year={2015}, month={Mar}, pages={2770–2775} }
 @article{mankiewicz_godwin_holler_turner_murashige_shamey_daniels_borski_2013, title={Masculinizing Effect of Background Color and Cortisol in a Flatfish with Environmental Sex-Determination}, volume={53}, ISSN={["1557-7023"]}, DOI={10.1093/icb/ict093}, abstractNote={Environmental sex-determination (ESD) is the phenomenon by which environmental factors regulate sex-determination, typically occurring during a critical period of early development. Southern flounder (Paralichthys lethostigma) exhibit temperature-dependent sex-determination that appears to be restricted to the presumed XX female genotype with the extremes of temperature, both high and low, skewing sex ratios toward males. In order to evaluate other environmental factors that may influence sex-determination, we investigated the influence of background color and cortisol on sex-determination in southern flounder. Experiments involving three sets of tanks, each painted a different color, were conducted at different temperatures using southern flounder of mixed XX-XY genotype. The studies involved rearing juvenile southern flounder in either black, gray, or blue tanks and sex-determination was assessed by gonadal histology. In both studies, blue tanks showed significant male-biased sex ratios (95 and 75% male) compared with black and gray tanks. The stress corticosteroid cortisol may mediate sex-determining processes associated with environmental variables. Cortisol from the whole body was measured throughout the second experiment and fishes in blue tanks had higher levels of cortisol during the period of sex-determination. These data suggest that background color can be a cue for ESD, with blue acting as a stressor during the period of sex-determination, and ultimately producing male-skewed populations. In a separate study using XX populations of southern flounder, cortisol was applied at 0, 100, or 300 mg/kg of gelatin-coated feed. Fish were fed intermittently prior to, and just through, the period of sex-determination. Levels of gonadal P450 aromatase (cyp19a1) and forkhead transcription factor L2 (FoxL2) messenger RNA (mRNA) were measured by qRT-PCR as markers for differentiation into females. Müllerian-inhibiting substance mRNA was used as a marker of males' gonadal development. Control fish showed female-biased sex ratios approaching 100%, whereas treatment with 100 mg/kg cortisol produced 28.57% females and treatment with 300 mg/kg cortisol produced only 13.33% females. These results suggest that cortisol is a critical mediator of sex-determination in southern flounder by promoting masculinization. This linkage between the endocrine stress axis and conserved sex-determination pathways may provide a mechanism for adaptive modification of sex ratio in a spatially and temporally variable environment.}, number={4}, journal={INTEGRATIVE AND COMPARATIVE BIOLOGY}, publisher={Oxford University Press}, author={Mankiewicz, Jamie L. and Godwin, John and Holler, Brittany L. and Turner, Poem M. and Murashige, Ryan and Shamey, Renzo and Daniels, Harry V. and Borski, Russell J.}, year={2013}, month={Oct}, pages={755–765} }