| Research shows the Hypothalamic-pituitary-gonadal axis of mammals is the important endocrine gland of animal reproductive activities and reproductive hormones secreted by the hypothalamus,pituitary gland and the gonads play an important role in regulating for reproductive physiological activities,such as mammals sexual development,maturation,sexual cycles etc.Gonadotropin-releasing hormone secreted by the hypothalamus prompts adenohypophysis to secrete gonadotropin.Gonadotropin involves in the regulation of estrus and ovulation of female reproductive process directly acting on the ovary.Ovarysecrets estrogen and progesterone,estrogen could encourage the development and the maturation of female reproductive organs inside and outside,breast,uterus and follicles,the hyperplasia of endometrial,adjust and control hormone secretion of the hypothalamus,and the pituitary gland;Progesterone helps to promote the development of the genital tract and maintains livestock pregnancy and prevents miscarriage.Different stages of the estrous cycle in mammals,the concentration of four main reproductive hormone in plasma has a significant dynamic change rule,and the relationship between four kinds of hormone is different because of the differences between species.So far,the dynamic study of reproductive hormone secretion in the estrous cycle was not reported about Tibetan sheep.So studing the dynamic changes of Tibetan sheep reproductive hormone secretion has important scientific significance and application value to reveal the Tibetan sheep reproductive regulation mechanism,and improve the performance of animal breeding and production.In order to study the Ganjia Tibetan sheep estrous cycle dynamic change rules of reproductive hormone secretion in plasma and the relationship with the Tibetan sheep reproductive regulation,this research studied the dynamic change rule of follicle stimulating hormone(FSH),luteinizing hormone(LH),estrogen(E)and progesterone(P)of the plasma of Gansu Tibetan sheep's estrous cycle in different stages.Select 48 Ganjia Tibetan sheep aged 2.5 ~ 3.5,normal healthy not pregnant females as a group estrus cycle in Tibetan sheep breeding season and be divided intofour groups according to the different stages of the estrus cycle:proestrus,estrus,late estrus,the affection between periods.The levels of follicle-stimulating hormone(FSH),luteinizing hormone(LH),progesterone(P)and estrogen(E)of proestrus,estrus,late estrus,between period in plasma were measured by using enzyme-linked immunosorbent assay(ELISA)and analyzed the estrus cycle dynamic change rule.The results are as follows:1.The characteristics of FSH secretion during the estrous cycle were as follows:The secretion of FSH is the highest(3.406 ± 0.294 m IU/m L)in the estrus,reduced to(2.492 ± 0.641 m IU/m L)in the late estrus,began to rise in the between the season,achieved(2.727 ± 0.603 m IU/m L)in the proestrus,and the secretion of FSH in the heat was significantly higher than that of the late estrus,between feeling and proestrus secretion(P<0.01);2.The characteristics of LH secretion during the estrous cycle were as follows:The secretion of LH in estrus,late estrus,season,proestrus was respectively(4.145 ±0.260 m IU/m L),(3.923 ± 0.432 m IU/m L),(4.377 ± 0.250 m IU/m L)and(4.375± 0.466 m IU/m L),Between late estrus was significantly lower than heat,season and proestrus(P < 0.05);3.The characteristics of P secretion during the estrous cycle were as follows: The secretion of P was the highest(18.039 ± 1.596 ng/m L),reduced to(16.196 ± 4.183ng/m L)in the heat and the secretion of P in the late estrus rose slowly and achieved to(17.127 ± 2.857 ng/m L)in the between the season,Proestrus was significantly higher than the heat and the late estrus(P < 0.05);4.The characteristics of E secretion during the estrous cycle were as follows:The secretion of E was the lowest(29.625 ± 3.166 pg/m L)in proestrus,rose to(36.035± 2.784 pg/m L)in the heat and achieved to the highest in the late estrus,then reduced to(35.531 ± 6.385 pg/m L)in the between the season,the secretion of E in the between the season was significantly higher than that of proestrus(P < 0.01),that of late estrus issignificantly higher than heat,between season and proestrus(P <0.01)and that of proestrus is significantly lower than between the season and heat(P <0.01).The study results could provide the test data for further research in Gansu Tibetan sheep's reproductive hormones regulation of reproduction,the role of different developmentperiod of follicles and the influence of reproductive performance.Provide theoretical basis for the research on female mammals estrus and ovulation reproductive endocrine regulation mechanism in the regulation of activities,the animal breeding and reproduction and artificial improve production performance. |
PDF Full Text Request