| Jining Gray goat is one of the species for using its leather in China. One of the important characteristic of Jining Gray goat is that they have a high reproductive ability, the average yean is 293.7%. The breeding performance of Jining Gray goat was regulated by reproduction hormone, so we should master the endocrine mechanism of the FSH, LH, E2 and P. Melatonin can restrain the release of GnRH and GTH by effect the hypothalamus and the pituitary, then regulate the breeding ability.GnRH is the informational molecule in the hypothalamic-pituitary- gonadal axis, it can regulate the secrete of GTH and gonadal hormone by effect the pituitary and genitical gland directly. But its function must be mediated by GnRHR. We investigate the distribution of GnRHR in pituitary and ovary of Jining Gray goat by the immunohistochemical method, thus we can provid the morphology data for the genesiology and physiology.Experiment 1. The Secretory Characteristics of GTH and gonadal hormone of Jining Gray goat during the Oestrus cycleThe jugular vein blood samples of Jining Gray goat were collected during the oestrus cycle.The secretory characteristics of FSH,LH,E2 and P were measured using radioimmunoassay system (RIA). There were four secretory peaks of FSH,LH and E2 were found during the oestrus cycle.The secretory peaks of FSH was two days later than that of LH. The secretory peaks of E2 appeared with LH at the same time except the 3rd secretory peaks.The P increased gradually from the 5th day and maintained the high concentration in the anoestrus(P>0.05),then decreased rapidly in the 18th.The secretion of FSH and LH were pulsatile during the oestrus and anoestrus,the estrogens and progesterone were wavelike. Furthermore,the pulse frequency of FSH during the oestrus was lower than the anoestrus(P>0.05), on the contrary ,the pulse frequency of LH during the anestrous was higher than the anoestrus (P>0.05).Experiment 2. The Secretory Characteristics of melatonin of Jining Gray goat in different reasonsFor studying the endocrine mechanism about seasonal empathema of Jining Gray goats, the principle of the melatonin concentration in peripheral blood and serotonin contents in pineal body were tested by radioimmunoassay and immunohistochemistry in vernal equinox, summer solstice, autumnal equinox and winter solstice. The results indicated that: the concentration of melatonin showed circadian rhythm in peripheral blood; it reached the maximum at midnight and minimum at midday. Melatonin contents associated with seasonal changes. At night, the average concentration of melatonin in the summer solstice was the highest than other seasons (p<0.01), no difference between the vernal equinox and the autumn equinox (p>0.05), and the concentration of melatonin in this three seasons were significant higher than which in the winter solstice (p<0.05). At daytime, melatonin contents showed no difference in all seasons (p>0.05). The area of serotonin-positive cells was the smallest in summer, the largest in winter in pineal body. There were no significant difference between spring and autumn (p>0.05).Experiment 3. Immunohistochemistry research of GnRHR in the pituitary body and ovary of Jining Gray goatThe structure and the distribute of GnRHR in the pituitary body and ovary were studied using immunohistochemical method in Jining Gray Goat. Results revealed that there are a lot of GnRHR positive cell in cytoplasm of pituitary body and ovary., The proportion of GnRHR positive cell is 31.5% in total cellular score of the adenohypophysis. In the ovary, the GnRHR positive cell reside in secondary follicle, mature follicle, corpus luteum, corpus albicans and atretic follicle. In mature follicle the ratio of GnRHR positive cell were higher than the secondary follicle (P>0.05), but the mean optical density are similar (P>0.05). In corpus luteum the ratio of GnRHR positive cell are significantly littler than which in mature follicle (P <0.05), extremely significantly higher than which in corpus albicans and atretic follicle (P <0.01). |
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