@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} }
 @article{johnstone_mills_alyea_thomas_borski_2013, title={Characterization of membrane receptor binding activity for cortisol in the liver and kidney of the euryhaline teleost, Mozambique tilapia (Oreochromis mossambicus)}, volume={192}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2013.06.025}, abstractNote={Glucocorticoids (GCs) regulate an array of physiological responses in vertebrates. Genomic GC actions mediated by nuclear steroid receptors require a lag time on the order of hours to days to generate an appreciable physiological response. Experimental evidence has accumulated that GCs, can also act rapidly through a nongenomic mechanism to modulate cellular physiology in vertebrates. Causal evidence in the Mozambique tilapia (Oreochromis mossambicus) suggests that the GC cortisol exerts rapid, nongenomic actions in the gills, liver, and pituitary of this euryhaline teleost, but the membrane receptor mediating these actions has not been characterized. Radioreceptor binding assays were conducted to identify a putative GC membrane receptor site in O. mossambicus. The tissue distribution, binding kinetics, and pharmacological signature of the GC membrane-binding activity were characterized. High affinity (Kd=9.527±0.001 nM), low-capacity (Bmax=1.008±0.116 fmol/mg protein) [(3)H] cortisol binding was identified on plasma membranes prepared from the livers and a lower affinity (Kd=30.08±2.373 nM), low capacity (Bmax=4.690±2.373 fmol/mg protein) binding was found in kidney membrane preparations. Competitors with high binding affinity for nuclear GC receptors, mifepristone (RU486), dexamethasone, and 11-deoxycorticosterone, displayed no affinity for the membrane GC receptor. The association and dissociation kinetics of [(3)H] cortisol binding to membranes were orders of magnitude faster (t1/2=1.7-2.6 min) than those for the intracellular (nuclear) GC receptor (t1/2=10.2h). Specific [(3)H] cortisol membrane binding was also detected in the gill and pituitary but not in brain tissue. This study represents the first characterization of a membrane GC receptor in fishes and one of only a few characterized in vertebrates.}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Johnstone, William M., III and Mills, Kathryn A. and Alyea, Rebecca A. and Thomas, Peter and Borski, Russell J.}, year={2013}, month={Oct}, pages={107–114} }
 @article{seale_yamaguchi_johnstone_borski_lerner_grau_2013, title={Endocrine regulation of prolactin cell function and modulation of osmoreception in the Mozambique tilapia}, volume={192}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2013.05.011}, abstractNote={Prolactin (PRL) cells of the Mozambique tilapia, Oreochromis mossambicus, are osmoreceptors by virtue of their intrinsic osmosensitivity coupled with their ability to directly regulate hydromineral homeostasis through the actions of PRL. Layered upon this fundamental osmotic reflex is an array of endocrine control of PRL synthesis and secretion. Consistent with its role in fresh water (FW) osmoregulation, PRL release in tilapia increases as extracellular osmolality decreases. The hyposmotically-induced release of PRL can be enhanced or attenuated by a variety of hormones. Prolactin release has been shown to be stimulated by gonadotropin-releasing hormone (GnRH), 17-β-estradiol (E2), testosterone (T), thyrotropin-releasing hormone (TRH), atrial natriuretic peptide (ANP), brain-natriuretic peptide (BNP), C-type natriuretic peptide (CNP), ventricular natriuretic peptide (VNP), PRL-releasing peptide (PrRP), angiotensin II (ANG II), leptin, insulin-like growth factors (IGFs), ghrelin, and inhibited by somatostatin (SS), urotensin-II (U-II), dopamine, cortisol, ouabain and vasoactive intestinal peptide (VIP). This review is aimed at providing an overview of the hypothalamic and extra-hypothalamic hormones that regulate PRL release in euryhaline Mozambique tilapia, particularly in the context on how they may modulate osmoreception, and mediate the multifunctional actions of PRL. Also considered are the signal transduction pathways through which these secretagogues regulate PRL cell function.}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Seale, A. P. and Yamaguchi, Y. and Johnstone, W. M., III and Borski, R. J. and Lerner, D. T. and Grau, E. G.}, year={2013}, month={Oct}, pages={191–203} }
 @article{picha_strom_riley_walker_won_johnstone_borski_2009, title={Plasma ghrelin and growth hormone regulation in response to metabolic state in hybrid striped bass: Effects of feeding, ghrelin and insulin-like growth factor-I on in vivo and in vitro GH secretion}, volume={161}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2009.01.026}, abstractNote={The regulation of growth hormone (GH) secretion by ghrelin during variable metabolic states is poorly understood. We examined plasma GH and ghrelin in hybrid striped bass (HSB) undergoing seasonally-based feeding and temperature manipulations. Fasting for 21 days (d) at 24 degrees C resulted in catabolism and up-regulation of plasma GH and ghrelin relative to fed controls. Continued fasting during cold-banking (14 degrees C, 90 d) resulted in a further 43-fold increase in ghrelin while GH remained elevated. A subsequent 19 day refeeding period at 24 degrees C elicited hyperphagic and compensatory growth responses, accompanied by declines in ghrelin and GH. We then tested the role of ghrelin in stimulating GH release in vivo and in vitro. Intraperitoneal injections of ghrelin resulted in dose-dependent increases in plasma GH after 6 hours (h). Ghrelin also increased GH release from HSB pituitaries during 6h incubations. Lastly, we assessed how metabolic state, ghrelin and insulin-like growth factor-I (IGF-I) affect in vitro pituitary GH release. Spontaneous GH release was 5.2-fold higher from pituitaries of fasted compared with fed animals. Ghrelin was equally effective in stimulating GH release from pituitaries of fed and starved animals, while it was ineffective in enhancing GH release from pituitaries of starved (21 d) then refed (4d) HSB. Incubation with IGF-I inhibited GH release regardless of metabolic state. These studies are the first to show that seasonally-based periods of feed deprivation and low temperature yield sustained increases in GH secretion that are likely mediated, at least partially, through elevated ghrelin, reduced IGF-I negative feedback and fasting-induced spontaneous GH release.}, number={3}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Picha, Matthew E. and Strom, Christina N. and Riley, Larry G. and Walker, Alicia A. and Won, Eugene T. and Johnstone, William M. and Borski, Russell J.}, year={2009}, month={May}, pages={365–372} }