ABSTRACT
BACKGROUND/AIM: Serum levels of leptin, the adipocyte-derived hormone regulating food intake and energy expenditure in mammals, have been found to be increased in cirrhotic patients. The aim of the present study was to investigate leptin serum level in relation to anthropometric features and liver function in patients with viral chronic hepatitis or liver cirrhosis. METHODS: Serum leptin levels were determined by radioimmunoassay in 30 male and 10 female patients with chronic hepatitis, in 42 male and 10 female patients with liver cirrhosis, and in four respective control groups. Liver function was evaluated by the monoethylglycinexylidide formation test. Body mass index and body fat mass were estimated by weight, height and skinfold thickness measurements. RESULTS: Compared with controls, absolute serum leptin levels were significantly (p<0.01) lower in chronic hepatitis patients and similar in cirrhotic patients. Leptin serum levels were significantly (p<0.05) higher in cirrhotic than in chronic hepatitis patients. When expressed in relation to body fat mass, the above differences persisted; however, cirrhotic females showed significantly (p<0.05) higher serum leptin values than controls. Serum leptin values correlated negatively (p<0.01) with monoethylglycinexylidide serum values in all groups of patients. CONCLUSIONS: In patients with chronic viral liver disease, serum leptin levels tend to increase as liver function worsens. This may reflect a decline in the ability to downregulate energy expenditure as an adaptation to anorexia and/or to defective substrate utilisation due to liver disease and may negatively influence body weight homeostasis in these patients.
Subject(s)
Hepatitis B, Chronic/blood , Hepatitis C, Chronic/blood , Leptin/blood , Lidocaine/analogs & derivatives , Liver Cirrhosis/blood , Adipose Tissue/pathology , Adult , Female , Hepatitis B, Chronic/complications , Hepatitis B, Chronic/pathology , Hepatitis C, Chronic/complications , Hepatitis C, Chronic/pathology , Humans , Lidocaine/blood , Liver Cirrhosis/pathology , Liver Cirrhosis/virology , Male , Middle Aged , Organ Size , Reference ValuesABSTRACT
To investigate the possibility that the aging process may affect the diurnal variation in serum leptin in humans, serum leptin levels were measured by a sensitive radioimmunoassay method in 12 elderly (aged 72 to 87 years) and 10 middle-aged (35 to 50 years) lean male subjects. Fasting blood samples (4 mL) were drawn at 8:00 AM, and then every 4 hours until 10:00 PM and every 2 hours from 12:00 midnight to 8:00 AM of the next morning. Circadian rhythmicity analysis was performed using the cosinor method. In elderly subjects, serum leptin levels showed a significant diurnal rhythm, which was similar to that observed in controls. Single cosinor analysis showed a significant rhythm in eight of 12 elderly subjects and in all middle-aged subjects but one. Compared with middle-aged subjects, similar mesor mean values (7.8 +/- 1.0 v 8.1 +/- 0.8 ng/mL) but a decreased amplitude (1.4 +/- 0.3 v 2.3 +/- 0.2 ng/mL) and an earlier acrophase (11:56 PM v 2:04 AM) were observed in the elderly. The data demonstrate that the diurnal variation in serum leptin is generally preserved in the elderly. However, the amplitude of leptin diurnal excursion undergoes a reduction with advancing age. It can be speculated that the blunted diurnal variation in serum leptin observed in the elderly may result in an alteration of the afferent signal in the adipose tissue-central nervous system homeostatic loop.
