Paper Information

Title: 

ROLE OF LEPTIN IN AGE & SEX RELATED RELEASE OF GONADOTROPIN FROM THE PITUITARY GLAND

Type: SPEECH
Author(s): ABDUL SAEED S.,AMBREEN I.,NAHEED A.
 
 
 
Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2007Volume 18
 
 
Abstract: 

Leptin is a hormone secreted by the adipose tissue, encoded by the obese (ob) gene. It provides information to the brain about the status of the fat stored in the body. It was observed in mice that a mutation in the gene ob renders these animals infertile with atrophic reproductive organs. Leptin is closely involved in the patho-physiology of gynaecological and obstetric disorders.This study was planned to investigate the direct effect of leptin on the release of gonadotropin from the rat pituitary glands at different stages of life from pre-pubertal to pubertal stage in male and female animals. Male and female rats of pre pubertal and pubertal age groups were used. Rats were killed by decapitation and anterior pituitary glands were dissected out. Cells were isolated by enzymatic dispersion technique and incubated for 48 h in CO2 incubator for 48 h. At the end of the incubation, media were removed and cells were incubated for four hours with leptin (10-12 - 10-6 M). At the end of incubation, media were collected and kept frozen until the measurement of bioactive LH by mouse Leydig cell LH bioassay.At all doses, Leptin significantly stimulated (p<0.05) basal LH secretion from cultured peripubertal and pubertal female's anterior pituitaries . At a dose of 10-12 M, , Leptin significantly stimulated 309 % of basal perpubertal LH and 220% of basal neonatal LH, compared to control (1549µIU ± 301 and 3907.5 ± 311 ) respectively. Where as only 10-12 M doses brought significant 71.01 % stimulation (p<0.05) of basal LH (3312µIU ± 163) from neonatal ant. Pituitaries. In neonatal males, Leptin significantly stimulated (p<0.05) 32% of basal LH secretion at 10-6 M dose only, compared to control 395 µIU ±0. where as in peripubertal animals 10-10 M dose significantly (p<0.05) increased 41% of basal LH secretion(23526 ± 982 µIU) and in adult animals 10-12 and 10-10M dose of leptin were able to brought significant (p<0.05) change in basal LH secretion. In adult females all doses of leptin significantly increased (p<0.05) GnRH stimulated LH secretion where as significant inhibition (p<0.05) with all doses of leptin was observed in peripubertal animals. Only 10-6 M dose showed significant 69% stimulation (p<0.05) from neonatal ant.pituitaries, compared to GnRH alone (32472µIU ± 2059). In adult males 10-10 M dose of leptin significantly 60% increased (p<0.05) GnRH stimulated LH secretion compared to GnRH alone (14593µIU ± 447). Where as significant inhibition (p<0.05) at 10-12 and 10-10 M dose of leptin was observed in neonatal animals. only 10-6 M dose showed significant 17.8% stimulation (p<0.05) from peripubertal ant.pituitaries, compared to GnRH alone (17175µIU ± 1085). On the basis of our findings we can conclude that there is a gradual increase in the responsiveness of the pituitary gland to leptin and female pituitaries become responsive to leptin much earlier compared with male. Moreover, this Effect is much more intense on the female pituitaries than on males. This would be possibly due to lack of adequate number of receptors in pituitary from a young animal compared with an adult.

 
Keyword(s): 
 
Yearly Visit 7   tarjomyar
 
Latest on Blog
Enter SID Blog