Scientist proved stress will kill you...

When human is under stress, NPV level is increased and it weakens immune systems to get human body to get sick.

Neuropeptide Y (NPY)
NPY, a candidate anabolic effector signalling molecule, stimulates energy intake. Prominent among anabolic effector pathways is a circuit containing neuropeptide Y (NPY).

Injection of NPY into cerebral ventricles or directly into the hypothalamus of rats potently stimulates food intake and decreases energy expenditure while simultaneously inducing lipogenic enzymes in liver and white adipose tissue.

Consequently, continuous or repeated central administration of NPY leads readily to obesity.

Because NPY gene expression and secretion of the NPY peptide in the hypothalamus are increased during active depletion of body fat stores and /or reduced leptin/insulin signalling to the brain, NPY meets the criteria for an anabolic signalling molecule.

Moreever, leptin inhibits arcuate nucleus NPY gene expression and genetic knockout of NPY reduces hyperphagia and obesity in ob/ob mice, indicating that the full response to leptin deficiency requires NPY signalling.The hyperphagic response to insulin-deficient diabetes is similarly accompanied by increased hypothalamic NPY synthesis and release, and this response is blocked by insulin administration, either systemically or directly into the brain.

Schwart M.W., et al. Nature 404, 661-671(2000) NPY is a member of the pancreatic polypeptide (PP) hormone family that includes also PP and Peptide YY (PYY). Several important physiological activities such as induction of food intake, inhibition of anxiety, increase in memory retention, presynaptic inhibition of neurotransmitter release, vasoconstriction and regulation of ethanol consumption have been attributed to NPY.

Strong central influence of NPY in feeding behavior:

• Injection of NPY into the hypothalamus increases food intake

• High NPY levels are correlated with Leptin

• NPY-knockout can reduce obesity in leptin deficient mice.

Two distinct Y-receptor subtypes Y1 and Y5 have been attributed to mediate the stimulatory effect of NPY on food intake.

NPY, PYY, [Leu31, Pro34]-NPY and three N-terminally truncated analogs, NPY(2-36), NPY (3-36) and PYY (3-36) and PYY(3-36) have been shown to increase food intake. Recently, the first analog of neuropeptide Y (NPY), [Ala31, Aib32]-NPY has been developed with highly selective affinity for Y5-receptor (6 nM).

In vivo adminstration of the [Ala31, Aib32]-NPY significantly stimulated feeding in rats.

Cabrele C. et al, The first selective agonist for the neuropeptide Y Y5-receptor increases food intake in rats. (JBC August 15, 2000)