Search NEL Online

Journal Article 2005; 26(4): 293-296 PubMed PMID: 16135994 Citation  Keywords:  Adult, Energy Metabolism:physiology, Female, Humans, Insulin:blood, Intracellular Signaling Peptides and Proteins:blood, Leptin:blood, Middle Aged, Neuropeptide Y:blood, Neuropeptides:blood, Obesity:blood, Orexins, Radioimmunoassay,.   

OBJECTIVE: It has been reported that the peptides such as orexins, neuropeptide Y (NPY) and leptin may play an important role in the regulation of appetite and energy metabolism. The interaction between leptin, orexins and NPY, as well as between peptides and insulin and cortisol in the different nutritional states have been investigated in animals. However, at present this relationship is poorly understood in humans.

RESEARCH METHODS: Material consisted of 36 obese women and 16 lean women. Plasma orexin A, orexin B, neuropeptide Y (NPY), leptin, insulin concentrations were measured with RIA methods.

RESULTS: Plasma orexin A concentrations were significantly lower in obese women as compared with control group. Plasma orexin A was significantly lower in severe obesity (BMI > 40 kg/m2) than that in moderate obesity (BMI < 40 kg/m2). Plasma orexin B concentrations did not change. However, plasma NPY, leptin and insulin levels were markedly higher in obese women, especially in severe obesity.

CONCLUSIONS: Our results confirmed the thesis that orexin A, NPY, leptin play an important role in the regulation of energy metabolism in humans. In obesity the activity of these peptides is disturbed....

Read abstract  Full text PDF

Journal Article 2001; 22(5): 349-355 PubMed PMID: 11600877 Citation  Keywords:  Animals, Appetite Regulation:drug effects, Energy Metabolism:drug effects, Estradiol:blood, Female, Follicle Stimulating Hormone:blood, Galanin:blood, Hormones:blood, Leptin:analysis, Luteinizing Hormone:blood, Neuropeptide Y:blood, Neuropeptides:blood, P.   

OBJECTIVES: Some hormonal disturbances were demonstrated in starvation. Leptin, NPY and galanin play an important role in the control of appetite and in the mechanism of hormone release.

METHODS: In order to evaluate the effect of starvation on the relationship between leptin, neuropeptide Y (NPY) galanin and pituitary and gonadal hormones release, plasma leptin, NPY and galanin as well as serum LH, FSH, prolactin (PRL), estradiol, progesterone levels in non-starved female rats (in diestrus) and after 72 hrs of starvation were measured with RIA methods. Effects of leptin, NPY and galanin administration on pituitary and gonadal hormones were investigated in vivo and in vitro experiments.

RESULTS: Plasma leptin, NPY and galanin as well as serum estradiol and progesterone concentrations were significantly lower in starved rats as compared with non-starved rats. However serum prolactin level was significantly higher in starved rats. Opposite effects after leptin and NPY administration on hormone release in vivo and in vitro experiments were observed in non-starved rats. However, in starved rats we did not find changes in pituitary and gonadal hormones release after leptin, NPY and galanin injection or the hormonal response was blunted.

CONCLUSIONS: 1) The disturbances in neuropeptides activity and in hormones release were observed in starvation. 2) Leptin, NPY and galanin have direct and indirect effects on pituitary and gonadal hormones release. 3) In starvation the hormonal response to leptin, NPY and galanin is impaired....

Read abstract  Full text PDF