Neuroendocrine function

Melatonin. Melatonin (A/-acetyl-5-metlioxytryptaniine) [73-31-4] C 2H gN2O2(250) is secreted from the pineal gland and retina during dark periods of the vertebrate circadian rhythm (65). Melatonin regulates biological rhythms and neuroendocrine function and is formed from serotonin (5-HT). 

NT has been impHcated in neuroendocrine function, thermal and circadian regulation, cardiovascular and digestive system function, nociception, and in psychoses as a DA modulator. 

Steroid Hormones and Neurosteroids. Steroids (qv) can affect neuroendocrine function, stress responses, and behavioral sexual dimorphism (78,79) (see Steroids). Mineralocorticoid, glucocorticoid, androgen, estrogen, and progesterone receptors are localized in the brain and spinal cord. In addition to genomic actions, the neurosteroid can act more acutely to modulate the actions of other receptors or ion channels (80). Pregnenolone [145-13-17, ( ) dehydroepiandosterone [53-43-0] C H2 02 (319) are excitatory neurosteroids found in rat brain, independent of adrenal... 

Besides behavior and blood pressure, catecholamine neurons also have important roles in other brain functions. Regulation of neuroendocrine function is a well-known action of catecholamines for example, DA agonists reduce semm prolactin concentration, especially in conditions of hypersecretion. Ingestive behavior can be modulated by brain catecholamines, and some appetite-suppressing dmgs are beheved to act via catecholaminergic influences. Catecholamines also participate in regulation of body temperature. 

Feral and LeGall" have suggested that TBT may affect the neuroendocrine system, interfering with the release of a retrogressive factor from the cerebropleiiral ganglia. The effects of TBT on neuroendocrine function merit further study. 

HT modulates neuroendocrine function 239 5-HT modulates circadian rhythmicity 239 5-HT modulates feeding behavior and food intake 239 Not only does 5-HT have important physiological effects of its own but it is also the precursor of the hormone melatonin 240... 

Perturbation of the 5-HT system can elicit changes in a wide variety of behaviors. Furthermore, drugs that act on serotonergic neurons and their receptors are used to treat diseases such as depression, anxiety disorders and schizophrenia. Thus, 5-HT has been implicated in the regulation of many behaviors and physiological processes. The involvement of 5-HT in three areas - neuroendocrine function, circadian rhythms and feeding behavior - will be highlighted for illustrative purposes. 

Owen, D., Andrews, M.H., and Matthews, S.G., Maternal adversity, glucocorticoids and programming of neuroendocrine function and behaviour, Neurosci.Biobehav. Rev., 29, 209, 2005. 

Meltzer, H. Y., Fang, V. S., Gudelsky, G., Manov, G., Simonovic, M., and Wiita, B. (1981) Effect of indole hallucinogens on neuroendocrine function in man and laboratory animals. Abstract, p. 47, Annual Meeting of the American College of Neuropsychopharmacology, Coronado, California. 

Uphouse L. 1985. Effects of chlordecone on neuroendocrine function of female rats. 

Physioiogicai There is an extensive literature that deals with the effects ginseng on CNS function, but effects are also seen in neuroendocrine function, carbohydrate and lipid metabolism, the immune system, and cardiovascular function (Gillis 1997). Ginsenosides induce a decrease in heart rate and have biphasic effects on blood pressure, with decreases preceded by a slight increase (Kaku et al. 1975). Ginsenoside Rgl had the most potent effects on blood pressure. Little or no effect is observed on respiration. 

Grossman A. (1983). Brain opiates and neuroendocrine function. Clin Endocrinol Metab. 12(3) 725-46. 

To further dissect CRH/CRHRl central nervous system pathways modulating behavior from those regulating neuroendocrine function, a region-specific, conditional knockout mouse line CaMKII Cre) was generated... 

Interestingly, while peripheral neuroendocrine function appears normal in patients with panic disorder, decreased basal cortisol concentrations have been reported in most studies in PTSD patients. This relative hypocortisolism occurs in the context of increased feedback inhibition of the HPA axis (see Yehuda, 2000). However, a dissociation between central and adrenocortical (re)activity has been found in animal models of severe early-life stress as well as in abused children and women, suggesting that adrenal dysfunction may, at least in part, contribute to hypocortisolism in PTSD. In the face of hypocortisolism, it seems surprising that hippocampal atrophy is one of the most prominent findings in patients with PTSD, including adult survivors of childhood abuse with PTSD (see Newport and Nemeroff, 2000). While increased glucocorticoid sensitivity of hippocampal cells may play a role in the development of hippocampal atrophy, another potential mechanism may involve toxic effects of markedly increased cortisol responses to everyday stress in patients with PTSD. 

It would be helpful if there were a peripheral measure of neurotransmitter function that could be used to guide medication selection and dosing, but unfortunately this has not yet been developed. Some measures can be obtained from the cerebro spinal fluid, but even these levels have not been established as a guide to treatment. Peripheral measures or related measures of neuroendocrine function (Birmaher et ah, 2000) may some day be useful guides. Likewise, pharmacogenetics may help select the most appropriate medication and dosage (Anderson and Cook, 2000, Chapter 7 in this volume). 

Nelson WH, Khan A, Orr WW Delusional depression, phenomenology, neuroendocrine function and tricychc antidepressant response. J Affect Disord 6 297-306, 1984... 

We emphasize that these theories are not mutually exclusive. Thus, a genetically determined membrane defect could produce a dysregulation in the neurotransmitter-receptor interaction. This, in turn, may impact second messenger systems within specific neural circuits, resulting in a disturbance of biological rhythms such as neuroendocrine function. 

Leptin is a peptide hormone secreted by adipocytes. Recombinant human leptin has been investigated for its potential as an antiobesity agent [105,106]. Women with hypothalamic amenorrhea display reduced levels of leptin. Leptin administration to these women improves reproductive and neuroendocrine function [107], Nasal administration of leptin to rats in the presence of either TDM (1) or LPC [108] caused a significant increase in serum leptin levels. Increased serum leptin levels were associated with reduced food consumption [108], The development of an effective nasal formulation of leptin containing an absorption enhancer may allow more frequent dosing with leptin and thereby overcome the limited efficacy observed following subcutaneous injections of large doses of this hormone. 

Unsworth WP, Taylor J A, Robinson JE. Prenatal programming of reproductive neuroendocrine function the effect of prenatal androgens on the development of estrogen positive feedback and ovarian cycles in the ewe. BiolReprod. 2005 72 619-627. 

The pharmacokinetics of morphine have been studied,201-203 as has its receptor binding,204-206 and its effects on hypothermia,207 on calcium uptake by synaptosomes208 and lysed synaptosomes,209 on metabolism of catecholamine in brain,210 on levels of corticosteroids and growth hormone in plasma,211 on leuteinising hormone,212 follicle-stimulating hormone,212 and prolactin,212-215 on neuroendocrine function,216 on brain function and biochemistry,217-226 on behaviour,227-240 on the gastrointestinal tract241 and on the cardiovascular... 

Jacoby, A. S. et al. (2002). Critical role for GALR1 galanin receptor in galanin regulation of neuroendocrine function and seizure activity. Brain Res. Mol. Brain Res. 107(2), 195-200. 

Clemett DA, Cockett MI, Marsden CA, Fone KC. Antisense oligonucleotide-induced reduction in 5-hydroxytryptamine7 receptors in the rat hypothalamus without alteration in exploratory behaviour or neuroendocrine function. J Neuro-chem 1998 71 1271-1279. 

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