Kiss 1 and GPR54 mRNA expression, endocrine profile, follicular development and onset of estrus following kisspeptin administration in pre-pubertal mithun heifers

Present study was undertaken to find out the effect of exogenous kisspeptin administration on Kiss1 and GPR54 mRNA expression, plasma endocrine profile and follicular development in pre-pubertal mithun heifers. Mithun heifers (20), age between 22–26 months, were selected and divided randomly into two groups (n=10). Before starting the experiment, all animals were examined by rectal palpation as well as through ultrasonography to ascertain the pre-pubertal status and blood samples were collected. All the animals in group A (treatment) were injected with kisspeptin (Metastin) @ 1.3 μg/kg body wt. at every 3 days interval up to day 20 while in group B (control), normal saline was injected as placebo. Blood samples were collected on the day of injection and on the day of estrus in control as well as treatment group. Trans-rectal ultrasonography was also conducted at every 3 days interval till day 20 and at estrus to study the follicular development. Results revealed significant increase in Kiss1 and GPR54 mRNA expression following kisspeptin administration as compared to control. Level of FSH and Estradiol 17β was higher in treatment group while no difference was reported in plasma progesterone in control and treatment group. Increased numbers of medium and large follicle were recorded in treatment group while control group showed only small and medium follicles. Early onset of estrus was reported in treatment group than in control. It may be concluded that exogenous administration of kisspeptin increased expression of Kiss1 and GPR54 mRNA; peripheral FSH and estradiol concentration, increased follicular growth and early onset of estrus in treated heifers than in control.