Systemic stress increases serum leptin level.
OBJECTIVE
Leptin, the product of the obese (ob) gene, is a circulating peptide mainly synthesized by adipocytes. Leptin inhibits food intake and decreases body weight. A recent report has suggested that the gastric mucosa is also the source of leptin, and that the stomach leptin also contributes to the regulation of the serum leptin level. The aim of the present study was to investigate the effect of water-immersion stress on serum, stomach and adipose tissue leptin levels to understand the relationship between stress and eating behavior.


METHODS
Male Sprague-Dawley rats were used in this experiment. The leptin level in the serum, gastric mucosa and adipose tissue was measured using ELISA system before and after the initiation of water-immersion stress.


RESULTS
The serum leptin level was significantly increased by water-immersion stress. The peak was observed 9 h after the initiation of the stress (P < 0.01). However, the gastric leptin level significantly decreased 6 and 9 h after the stress. The adipose tissue leptin level significantly increased 3 h after the stress.


CONCLUSIONS
The results suggest that changes in serum leptin levels could be associated with stimulation of leptin secretion from the gastric mucosa and leptin production in the adipose tissue by systemic stress and that leptin might be regulated by stress-related events.
Konishi
Noriaki
N
Department of Internal Medicine, Akita University School of Medicine, Akita, Japan.
Otaka
Michiro
M
Odashima
Masaru
M
Jin
Mario
M
Wada
Isao
I
Komatsu
Koga
K
Sato
Toshihiro
T
Kato
Sayuri
S
Matsuhashi
Tamotsu
T
Watanabe
Sumio
S
D017667:Adipocytes / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005500:Follow-Up Studies; D005753:Gastric Mucosa / Q000378:metabolism; D007101:Immersion / Q000009:adverse effects; D020738:Leptin / Q000097:blood* / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012720:Severity of Illness Index; D013312:Stress, Physiological / Q000209:etiology / Q000378:metabolism*
D015415:Biomarkers; D020738:Leptin