Background: KiSS-1 and its product, kisspeptin is necessary for puberty onset and proper adult gonadal function due to its stimulatory effect on the secretion of gonadotropin-releasing hormone (GnRH). Although the pathophysiological importance of KiSS-1 and kisspeptin is well known, the developmental patterns of expression of KiSS-1 genes and serum level of kisspeptin have not been explored to date.
Objective and hypotheses: We report herein the expression profile of KiSS-1 genes and serum level of kisspeptin in the rat at different developmental stages.
Method: Spraque-Dawley (SD) strain female rats were used. To analysis expression of KiSS-1 mRNA, samples were obtained from hypothalamus, pituitary and ovaries in female rats according to developmental stages. At the same time, blood samples were collected for analysis serum level of kisspeptin and luteinizing hormone (LH). The expression of KiSS-1 mRNAs was assessed by RT-PCR and the serum levels of kisspeptin and LH were analyzed by ELISA.
Results: The expressions of KiSS-1 gene in hypothalamus and ovary were increased according to developmental stages and were peaked at prepubertal stage (at day 27, respectively, 0.88±0.22, 0.54±0.25). However, there were no significant changes or correlations between developmental stages and KiSS-1 gene expression in pituitary. Serum kisspeptin level was also increased according to developmental stages. However, peak level of kisspeptin (35.43±3.60 pg/ml) was in pubertal stage at day 34. Serum LH level was also increased and peaked (23.29±15.24 ng/ml) at pubertal stage (at day 38). However, an increasing pattern was little delayed than that of kisspeptin level.
Conclusion: The expressions of KiSS-1 mRNA in hypothalamus and ovary, serum levels of kisspeptin and serum LH levels were increased according to developmental stages in rat in regular sequence. Therefore, serum kisspeptin levels can be an indication of KiSS-1 gene expression in hypothalamus and pubertal onset.
18 Sep 2014 - 20 Sep 2014