Short-term fasting abolishes the sex-related difference in GH and leptin secretion in humans.
We studied growth hormone (GH) and leptin secretion in eight male (age 29.3 +/- 1.2 yr, body mass index 22.2 +/- 0.5 kg/m(2)) and seven female normal subjects (28.0 +/- 0.8 yr, 20.1 +/- 0.7 kg/m(2)) before and after 36 h of fasting. In the fed state, 8-h mean GH and leptin concentrations were higher in females (P < 0.05 and P < 0. 0001, respectively). Fasting increased GH and decreased leptin in both sexes. There was significant interaction between gender and fasting (P < 0.05 for GH and P < 0.005 for leptin). Females showed a slighter increase in GH but a more marked decrease in leptin, so that there was no significant gender-related difference in GH and leptin after fasting. Fasting did not modify insulin-like growth factor (IGF) I, IGF binding protein (IGFBP)-3, acid-labile subunit, or GH binding protein; increased IGFBP-1 and free fatty acids (P < 0.0001) but decreased glucose (P < 0.001) and insulin levels (P < 0.05). In males, insulin levels were higher (P < 0.05) in the fed state and underwent deeper reduction after fasting (interaction P < 0.03). In conclusion, GH and leptin secretions are higher in women than in men in the fed but not in the fasting condition, which abolishes these gender-related differences in humans.
Maccario
M
M
Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Torino, 10126 Turin, Italy.
Aimaretti
G
G
Corneli
G
G
Gauna
C
C
Grottoli
S
S
Bidlingmaier
M
M
Strasburger
C J
CJ
Dieguez
C
C
Casanueva
F F
FF
Ghigo
E
E
D000328:Adult; D001786:Blood Glucose; D002352:Carrier Proteins / Q000097:blood; D002940:Circadian Rhythm / Q000502:physiology; D004958:Estradiol / Q000097:blood; D005215:Fasting / Q000097:blood*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006023:Glycoproteins / Q000097:blood; D019382:Human Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020738:Leptin / Q000097:blood / Q000378:metabolism*; D008297:Male; D012737:Sex Factors; D013739:Testosterone / Q000097:blood
D001786:Blood Glucose; D002352:Carrier Proteins; D005230:Fatty Acids, Nonesterified; D006023:Glycoproteins; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D020738:Leptin; C075944:insulin-like growth factor binding protein, acid labile subunit; D019382:Human Growth Hormone; D013739:Testosterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; C051815:somatotropin-binding protein