Lack of association between changes in plasma leptin concentration and in food intake during the menstrual cycle.
BACKGROUND
Changes in plasma leptin concentration and food intake occur during the menstrual cycle; because leptin regulates food intake, one could hypothesize that changes in plasma leptin concentration and in food intake are associated throughout the menstrual cycle. However, no data have ever been provided to support such a relationship. The aim of our study was to investigate, during the different phases of the menstrual cycle, (a) the changes in plasma leptin concentration and, if such changes were demonstrated, (b) the potential relationship between the changes in plasma leptin concentration and food intake.


METHODS
The study was designed as an observational study. The plasma leptin concentration was determined in 16 healthy, young women during different phases of the menstrual cycle. At the same time, the basal metabolic rate (BMR), respiratory quotient (RQ) and food intake (FI) were also determined.


RESULTS
The plasma leptin concentration increased throughout the menstrual cycle (P < 0.01 for trend) and was significantly correlated with plasma progesterone concentration (r = 0.55, P < 0.007, for follicular phase, r = 0.58, P < 0.02, for the periovulatory period and r = 0.57, P < 0.02, for the luteal phase). No significant differences in BMR and fasting RQ throughout the different phases of the menstrual cycle were found. In contrast, FI significantly declined in the periovulatory phase. No significant correlations between BMR, RQ and FI values and fasting plasma leptin concentration at all menstrual phases were found.


CONCLUSIONS
Changes in plasma leptin concentration and in food intake were found at different phases of the menstrual cycle. Nevertheless, no correlation among those parameters at any phase of the menstrual cycle was observed.
Paolisso
G
G
Department of Geriatric Medicine and Metabolic Diseases, II University of Naples, Naples, Italy. gpaoliss@tin.it
Rizzo
M R
MR
Mazziotti
G
G
Rotondi
M
M
Tagliamonte
M R
MR
Varricchio
G
G
Carella
C
C
Varricchio
M
M
D000328:Adult; D001481:Basal Metabolism; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D004435:Eating; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D020738:Leptin; D007986:Luteinizing Hormone / Q000097:blood; D008597:Menstrual Cycle / Q000097:blood / Q000502:physiology*; D010101:Oxygen Consumption; D011374:Progesterone / Q000097:blood; D011506:Proteins / Q000378:metabolism*; D012044:Regression Analysis; D012119:Respiration
D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; D011506:Proteins; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone