The
obese gene product--
leptin (LEP)--is a
hormone released from adipose tissue implicated in the regulation of nutritional state and energy balance. The aim of this study was to assess the relationship between plasma LEP levels and nutritional state, secretion of
hormones of the hypothalamic-pituitary axis, and personality traits in patients with
anorexia nervosa (AN). The study was performed in 22 women with AN aged 19.45 +/- 0.92 yrs, mean BMI of 15.48 +/- 0.29 kg/m2, 14 healthy women with normal body weight (NW), aged 29.71 +/- 2.4 yrs, mean BMI of 21.22 +/- 0.43 kg/m2, and 19 obese women without metabolic disorders (OTY), aged 34.5 +/- 2.65 yrs, mean BMI of 37.47 +/- 2.06 kg/m2.
Hormone levels were measured with RIA test kits. Psychological examination was carried out by means of Gough-Helibrun's and Catell's personality tests. Body mass index (BMI) and body composition, i.e. body fat mass (BF) and body fat percentage (%BF) were determined with a DEXA instrument (Lunar Co., WI, USA). Absolute plasma LEP levels and the LEP/%BF index were lowest in patients with AN whereas LEP/BF index did not differ among AN, NW, and OTY groups (Table 1). In all groups, LEP levels were positively correlated with BMI, BF, and %BF (Table 2). Plasma
neuropeptide Y (NPY),
beta-endorphin (B-EP), and
galanin (GAL) levels in AN were significantly higher than in NW and OTY groups (Table 3). Plasma GAL levels were positively correlated with LEP/BF and LEP/%BF in AN patients only. Moreover in the AN group, serum/plasma levels of
insulin (I),
insulin-like growth hormone-1 (IGF-1),
luteinizing hormone (LH),
follicle stimulating hormone (FSH),
estradiol (E2), and free
triiodothyronine (fT3) were significantly lower, and levels of
cortisol (F) significantly higher than in NW and OTY groups (Table 4). Plasma LEP levels in AN patients were positively correlated with IRI,
IGF-1, free
thyroxine (fT4), and FSH levels, and negatively correlated with
thyrotrophin (TSH) levels. Personality traits in patients with AN were significantly correlated with
hormone levels (Tables 5 and 6), BMI and body fat content (Table 6).
CONCLUSIONS: 1)
Leptin secretion from adipose tissue is not related to the nutritional state. 2) High levels of NPY, beta-EP, and GAL in AN confirm that
starvation is deliberate in these patients. Low LEP levels in AN may lead to secondary
amenorrhea and thyroid function disorders, as well as enhanced
cortisol and
growth hormone secretion of hypothalamic origin. A positive correlation between levels of LEP and IGF-1 and IRI may reflect mechanisms preserving adipose tissue and protecting from
hypoglycemia and
insulin resistance. A positive correlation between LEP and fT4 levels suggests a tendency to energy-sparing under conditions of low energy intake. Lack of correlation between LEP and F levels apparently reflects peripheral
cortisol resistance in
AN. 3) Both
undernutrition and abnormal
hormone secretion (LEP, F, fT3, IGF-1, LH, E2) are related to social self-withdrawal, defensive attitudes, low self-esteem and high level of self-supervision in AN.