Compare And Contrast Leptin And Ghrelin
Ghrelin and leptin are two hormones which are of great interest in appetite regulation. Leptin is commonly considered to be anorexigenic (i.e. appetite suppressant) while ghrelin is orexigenic (i.e. appetite stimulant).
They are secreted in a reciprocal rhythm, influenced by the neuropeptide Y (NPY) system in the hypothalamus which is acted upon by these afferent hormones. This highly specific system shows rhythmic secretion, imparting in turn the same pattern to the expression of appetite and feeding behavior.
Leptin and ghrelin on body weight
Leptin inhibits ghrelin in two ways; it reduces ghrelin secretion by gastric cells, and suppresses the expression of ghrelin receptors in the NPY system, therefore preventing the stimulation of feeding …show more content…
Leptin also increases the rate of thermogenesis and thus promotes weight maintenance.
Ghrelin, on the other hand, stimulates feeding and results in obesity. It is produced in the stomach and also in the hypothalamic subparaventricular zone, which has an appetite-stimulant action. Ghrelin levels rises before a meal, and goes down after meals.
Moreover, ghrelin levels fluctuate in accordance with changes in energy reserves in the body. Thus ghrelin is episodic in secretion, but the amplitude depends upon the feeding status. This hormone is also involved in the short-term regulation of human …show more content…
Ghrelin secreted in the stomach mucosa circulates to the brain and crosses the blood-brain-barrier. It acts together with locally secreted ghrelin in the hypothalamus to stimulate the NPY and other neurons in the ARC-PVN nucleus to stimulate appetite. This can be inhibited by Y1 receptor antagonists acting on the NPY neurons.
Leptin acts to reduce the synthesis, release, and biological actions of NPY in the ARC-PVN neuronal system via long leptin receptor activation. Yet leptinopenic mice (i.e. those with low levels of leptin) failed to develop a good appetite, though their ghrelin levels rose. Thus the hypothalamic restraint exercised by leptin overrides even a strong peripheral afferent signal by ghrelin.
Actions of ghrelin
There are several notable actions that ghrelin has on a human body:
• It regulates the blood glucose levels through reduced insulin secretion and by regulating the synthesis and breakdown of glucose and
They are secreted in a reciprocal rhythm, influenced by the neuropeptide Y (NPY) system in the hypothalamus which is acted upon by these afferent hormones. This highly specific system shows rhythmic secretion, imparting in turn the same pattern to the expression of appetite and feeding behavior.
Leptin and ghrelin on body weight
Leptin inhibits ghrelin in two ways; it reduces ghrelin secretion by gastric cells, and suppresses the expression of ghrelin receptors in the NPY system, therefore preventing the stimulation of feeding …show more content…
Leptin also increases the rate of thermogenesis and thus promotes weight maintenance.
Ghrelin, on the other hand, stimulates feeding and results in obesity. It is produced in the stomach and also in the hypothalamic subparaventricular zone, which has an appetite-stimulant action. Ghrelin levels rises before a meal, and goes down after meals.
Moreover, ghrelin levels fluctuate in accordance with changes in energy reserves in the body. Thus ghrelin is episodic in secretion, but the amplitude depends upon the feeding status. This hormone is also involved in the short-term regulation of human …show more content…
Ghrelin secreted in the stomach mucosa circulates to the brain and crosses the blood-brain-barrier. It acts together with locally secreted ghrelin in the hypothalamus to stimulate the NPY and other neurons in the ARC-PVN nucleus to stimulate appetite. This can be inhibited by Y1 receptor antagonists acting on the NPY neurons.
Leptin acts to reduce the synthesis, release, and biological actions of NPY in the ARC-PVN neuronal system via long leptin receptor activation. Yet leptinopenic mice (i.e. those with low levels of leptin) failed to develop a good appetite, though their ghrelin levels rose. Thus the hypothalamic restraint exercised by leptin overrides even a strong peripheral afferent signal by ghrelin.
Actions of ghrelin
There are several notable actions that ghrelin has on a human body:
• It regulates the blood glucose levels through reduced insulin secretion and by regulating the synthesis and breakdown of glucose and