Leptin(116-130) stimulates prolactin and luteinizing hormone secretion in fasted adult male rats.
Leptin is a hormone secreted by adipocytes with an important role in the control of feeding behavior and neuroendocrine function. Leptin stimulates in vivo LH secretion in fasted female rats and in vitro PRL secretion. Recent data indicate that leptin(116-130), an active fragment of the native molecule, exerts effects similar to those of the native peptide on body weight and food intake. The present study was carried out to determine whether this fragment is also able to stimulate LH and PRL secretion. Adult male rats fasted for 5 days were injected with saline or leptin(116-130) (15 microgram i.c.v.) and LH and PRL concentrations were measured thereafter at 15-min intervals during a 150-min period. Administration of leptin(116-130) increased the frequency of LH pulses (2.0 +/- 0.26 vs. 1.20 +/- 0. 37/150 min; p </= 0.05), mean LH levels (0.24 +/- 0.06 vs. 0.07 +/- 0.03 ng/ml; p </= 0.05), LH pulse amplitude (0.33 +/- 0.10 vs. 0.10 +/- 0.05 ng/ml; p </= 0.05) and the net LH secretion estimated by area under curve (AUC: 36 +/- 8.5 vs. 9 +/- 3.9 ng/ml/150 min; p </= 0.01). In addition leptin(116-130) increased the frequency of PRL pulses (2.83 +/- 0.48 vs. 1.33 +/- 0.21/150 min; p </= 0.05), trough PRL levels (5.71 +/- 0.99 vs. 2.72 +/- 0.32 ng/ml; p </= 0.01), mean PRL levels (13.02 +/- 0.92 vs. 5.89 +/- 0.51 ng/ml; p </= 0.01) and net PRL secretion (AUC: 1,625 +/- 171 vs. 658 +/- 46 ng/ml/150 min; p </= 0.05). In conclusion, these data show that leptin(116-130) stimulates LH and PRL secretion in fasted adult male rats.
Gonzalez
L C
LC
Department of Physiology, Faculty of Medicine, Córdoba University, Córdoba, Spain.
Pinilla
L
L
Tena-Sempere
M
M
Aguilar
E
E
D000367:Age Factors; D000818:Animals; D005215:Fasting / Q000502:physiology; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D007276:Injections, Intraventricular; D020738:Leptin / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012737:Sex Factors
D020738:Leptin; D010446:Peptide Fragments; D007987:Gonadotropin-Releasing Hormone; D011388:Prolactin; D007986:Luteinizing Hormone