The role of leptin in the regulation of pituitary hormones release.
OBJECTIVE
It has been reported that leptin plays an important role in the regulation of food intake and energy expenditure. There are controversial opinions about effects of leptin on the hormonal system. The aim of this study was to estimate the effect of leptin on pituitary hormones release after central and peripheral administration.


METHODS
Leptin was injected intracerebroventricularly (icv) in a dose of 0.5 microg/5microl aCSF (artificial cerebrospinal fluid) for 5 min in Wistar Kyoto rats. At 60 and 120 min after injections the animals were decapitated. Leptin in a dose of 10 microg in 300 microl of saline was administered intravenously (i.v). At 60 mins the animals were decapitated. Serum rLH, rFSH, rPRL, rTSH, rGH concentrations were measured with RIA methods.


RESULTS
After central (icv) injection of leptin we observed an increase of rGH, rTSH and a decrease of rPRL. However, after peripheral (iv) injection of leptin we found a decrease of rGH and rTSH and an increase of rPRL. We did not find any significant changes in LH and FSH after icv and iv injection of leptin.


CONCLUSIONS
The opposite effects of leptin on pituitary hormones release were observed due to the method of leptin administration. Leptin may play a modulating role in the mechanism of pituitary hormones release.
Baranowska
Bogusława
B
Neuroendocrinology Department, Medical Centre of Postgraduate Education, Marymoncka 99, 01-813 Warsaw, Poland. zncmkp@free.polbox.pl
Wolińska-Witort
Ewa
E
Martyńska
Lidia
L
Chmielowska
Magdalena
M
Baranowska-Bik
Agnieszka
A
D000818:Animals; D005260:Female; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D020738:Leptin / Q000008:administration & dosage / Q000494:pharmacology*; D010052:Ovariectomy; D010907:Pituitary Hormones / Q000097:blood / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011921:Rats, Inbred WKY
D020738:Leptin; D010907:Pituitary Hormones