WEISS*, S.L.; MOORE, M.C.: Testosterone and progesterone activate aggression in male tree lizards Neuroendocrine mechanisms regulating aggressive behavior are complex, and often no direct relationship between circulating hormone levels and aggression is found. For instance, in the face of identical testosterone levels, male tree lizards (Urosaurus ornatus) express one of two behaviorally-distinct reproductive strategies: “orange” […]

POWELL, Mickie/L*; SOWER, Stacia/A: Seasonal Estradiol Production in Three Size Classes of Atlantic Hagfish Hagfish are considered to be the oldest form of extant vertebrates in the Class of Agnatha. During the past ten years they have become the focus of a growing commercial fishery on the East Coast. Since there is little information on […]

RODGERS, Buel D; WEBER, Gregory M; KELLEY, Kevin M; LEVINE, Michael A: Nutritional regulation of myostatin mRNA in the tilapia In mammals, myostatin initiates myoblast differentiation by cell-cycle withdrawal and G1 growth arrest. Mice and cattle possessing null alleles for myostatin display a double muscled phenotype characterized by extreme skeletal muscle hypertrophy and hyperplasia. Our […]

KAJIMURA, S.; UCHIDA, K.; YADA, T.; HIRANO, T.; GRAU, E.G.: Interaction between Insulin-like growth factors (IGF-I and IGF-II) and growth hormone in the euryhaline tilapia, Oreochromis mossambicus Growth in vertebrates is controlled by the GH-IGF axis to an important degree. To better understand the interaction between IGFs and GH in teleosts, we studied the effects […]

RILEY, L. G.*; HIRANO, T.; RICHMAN III, N. H.; GRAU, E. G.: Growth Regulation in the Tilapia: Effect of Salinity and 17&alpha-Methyltestosterone (MT) Treatment Effects of salinity and MT treatment on growth and the growth hormone / insulin-like growth factor-I axis (GH/IGF-I) in the euryhaline tilapia, Oreochromis mossambicus were examined. Animals were raised in either […]

JOHN-ALDER, Henry B.; COX, Robert M.; LEO, Angela; SKELLY, Stephanie: Growth Inhibition by Testosterone in Eastern Fence Lizards (Sceloporus undulatus) In most populations of Sceloporus undulatus, adult females are about 10% larger than adult males, even when controlling for age. In our population, SSD arises because females grow faster than males prior to sexual maturation. […]

WARD, C. K.*; MENDONCA, M. T.: The Effect of Coal Fly Ash on Corticosterone, Testosterone and Weight in the Southern Toads, Bufo terrestris Southern toads (Bufo terrestris) are found during the breeding season at coal fly ash basins, which contain large concentrations of heavy metals, at the Savannah River Site, in Aiken, South Carolina. Toads […]

ZOZZARO, P.E.; CARR, J.A.: Peripheral Administration of Ovine Corticotropin-releasing Hormone Activates the Sympathetic Nervous System in Toads. Corticotropin-releasing hormone (CRH) plays a key role in the regulation of stress and arousal associated behaviors in mammals, and contributes to hyperglycemia and activation of the sympathetic nervous system (SNS) during stress. Work in mammals suggests that the […]

HAYWARD*, L.S.; WINGFIELD, J.C.: Laying Japanese Quail transfer corticosterone to egg yolk Exposure to maternal stress and elevated gluccocorticosteroids often has long term debilitating effects on developing mammals and fish. We addressed the question of how, if at all, elevated gluccocorticoids in the circulation of laying birds affect the development and phenotype of their offspring. […]

NEPHEW, B.C.; KAHN, S.A.; ROMERO, L.M.: Heart rate and behavior change independently of corticosterone following acute auditory and visual stressors Captive European starlings (Sturnus vulgaris) were subjected to five acute stressors: a visual stressor (strobe light), an auditory stressor (loud music), and disturbance by three different humans; their accustomed caretaker, an antagonist (the experimenter), and […]