Teleost Hormones

Cross references:   Fish   Osteichthyes (Bony Fish)    Teleosts  
Teleost Cortisol, etc.      Teleost Dominance Hierarchies    
Lamprey Hormones      Shark Hormones     Salamander Hormones    

Molecular evolution of fish neurohypophysial hormones: neutral and selective evolutionary mechanisms.
Only the abstract is available online. 
Chemical identification of neurohypophysial hormones from about 80 vertebrate species reveals that two evolutionary lineages can be traced in bony vertebrates, a vasopressin-like hormone line and an oxytocin-like hormone line, which were derived from the duplication of an ancestral gene that may have been present in agnathans.

Serotonin as a regulator of hypothalamic-pituitary-interrenal activity in teleost fish.  
Only abstract available online.  I may try to get PDF from the library.     
Evidence for the presence of a serotonin1A (5-HT1A) receptor subtype in the salmonid fish brain has recently been presented. In the present study the potent 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) was tested for its effect on plasma cortisol concentrations in rainbow trout (Oncorhynchus mykiss)."      
    "The results lends further support to the hypothesis that the brain serotonergic system plays a key role in integrating autonomic, behavioral and neuroendocrine stress-responses in fish as well as mammals, suggesting that not only the structural and biochemical organization, but also the function of the serotonergic system has been conserved during vertebrate evolution."  

Sex Steroids and Their Involvement in the Cortisol-Induced Inhibition of Pubertal Development in Male Common Carp  
Full length PDF available online for free.  Must download to copy. 
    "The onset and regulation of puberty is determined by functional development of the brain-pituitary-gonad (BPG) axis. Sex steroids produced in the gonads play an important role in the onset of puberty. Stress interferes with reproduction and the functioning of the BPG axis, and cortisol has frequently been indicated as a major factor mediating the suppressive effect of stress on reproduction.  
    Prolonged elevated cortisol levels, implicated in stress adaptation, inhibited pubertal development in male common carp (Cyprinus carpio). Cortisol treatment caused a retardation of pubertal testis development and reduced the LH pituitary content and the salmon GnRHa- stimulated LH secretion in vitro. A reduced synthesis of androgens also was observed.
    These findings suggest that the cortisol-induced inhibition of testicular development and the maturation of pituitary gonadotrophs are mediated by an effect on testicular androgen secretion. In this study, we combined cortisol treatment with a replacement of the testicular steroid hormones (testosterone and 11-oxygenated androgens) to investigate the role of these steroids in the cortisol-induced suppression of pubertal development.     
    The effect of cortisol on spermatogenesis was independent of 11-ketotestosterone, whereas the effect on the pituitary was an indirect one, involving the testicular secretion of testosterone."

Date unknown. Last reference 2004.  

Primary Structures and Multiplicity of Pancreatic Hormone in Fish 
Full length PDF available online for free.    
    "The pancreas contains several peptide hormones including insulin and glucagon which regulate nutrition metabolism and consequently growth. The primary structures and biochemical characters of these hormones are important information for the artificial synthesis of these hormones and the development of the immunoassay system. In fish, several species possess plural molecular forms of insulin and glucagons, and this phenomenon complicates the understanding of the physiological function of these hormones." 

Functions of melanin-concentrating hormone in fish -
  "Melanin-Concentrating Hormone (MCH) is a cyclic neuropeptide synthesized as a preprohormone in the hypothalamus of all vertebrates. Mammalian MCH plays an important role as a neurotransmitter or neuromodulator in regulating food intake and energy homeostasis."
  "This neuropeptide binds to G-protein-coupled seven transmembrane receptor[s] to mediate its functions. "  

Nonapeptides and Social Behavior in Fishes 

Hormones and Behavior   Volume 61, Issue 3    
I have PDF. 
    "The nonapeptide hormones arginine vasotocin and isotocin play important roles in mediating social behaviors in fishes. Studies in a diverse range of species demonstrate variation in vasotocin neuronal phenotypes across within and between sexes and species as well as effects of hormone administration on aggressive and sexual behaviors. However, patterns vary considerably across species and a general explanatory model for the role of vasotocin in teleost sociosexual behaviors has proven elusive.  
    We review these findings, examine potential explanations for the lack of agreement across studies, and propose a model based on the parvocellular AVT neurons primarily mediating social approach and subordinance functions while the magnocellular and gigantocellular AVT neurons mediate courtship and aggressive behaviors. Isotocin neuronal phenotypes and effects on behavior are relatively unstudied, but research to date suggests this will be a fruitful line of inquiry."  

Teleost Hormones
121205 - 1359