Title of Dissertation: GONADAL AND STEROID FEEDBACK REGULATION OF THE HYPOTHALAMUS-PITUITARY AXIS IN STRIPED BASS (Morone saxatilis) Ulrike Klenke, Doctor of Philosophy, 2006 Dissertation directed by: Professor Yonathan Zohar Center of Marine Biotechnology, University of Maryland Biotechnology Institute The objective of the present study was to expand our understanding of the mechanisms of gona...

An increase in activity of the pituitary-gonadal axis (PG-axis) and gonadal development are essential for the onset of spawning migration of chum salmon from the Bering Sea. In the Bering Sea, fish with larger body sizes initiated gonadal development and commenced spawning migration to the natal river by the end of summer. We thus hypothesized that insulin-like growth factor-I (IGF-I), a somato...

Chronic anxiety, depression or physical exertion-associated stress consistently activates the hypothalamic-pituitary-adrenal (HPA) axis. Each individual component of the HPA axis, such as CRH, ACTH, β-endorphin or glucocorticoid exerts deleterious effect on the hypo-thalamic-pituitary-gonadal (HPG) axis and subsequently leads to reproductive failure. Gonadotropin-releasing hormone (GnRH) secret...

Opiates and cocaine both have effects on adrenal and gonadal function. Opiates suppress the hypothalamic-pituitary adrenal (HPA) axis, whereas cocaine leads to HPA activation. Opiates also cause gonadal dysfunction in both men and women. During withdrawal from opiates and cocaine, the HPA axis is activated which may reinforce relapse behavior. This review describes these hormonal effects and ex...

Neuroendocrinology of the aging (male) gonadal and (male and female) somatotropic axes will be reviewed. A companion chapter discusses reproductive hormonal changes in aging women. Both the gonadal and growth-hormone/insulin-like growth factor (GH/IGF-I) axes function as ensembles. The ensembles comprise tripartite interactions among the brain (hypothalamus), anterior pituitary gland (gonadotro...

Adipose tissue produces factors, including adipokines, cytokines and chemokines which, when released, systemically exert endocrine effects on multiple tissues thereby affecting their physiology. Adipokines also affect the hypothalamic-pituitary-gonadal (HPG) axis both centrally, at the hypothalamic-pituitary level, and peripherally acting on the gonads themselves. Among the adipokines, leptin, ...

To regulate reproduction in mammals, internal and external status is communicated to the hypothalamic-pituitary-gonadal axis via a coordinated balance of stimulatory and inhibitory neurochemical systems. This review describes the neuroanatomical organization of the kisspeptin system in the hypothalamus, and summarizes its role in signaling hypothalamic GnRH neurons, namely: multimodal actions o...

background : electromagnetic fields are associated with production, transmission and use of electricity. in this  tudy we have investigated the effects of short and long time alternative magnetic fields' (amf, 50 hz) exposure on the secretion of hypothalamic-pituitary-gonadal axis in the male rats. methods : forty eight wistar male rats, same range of age and weight were divided into four group...