The animal models of subacute and chronic fluorosis were devel-oped with injection of large doses of NaF (IP)and drinking water containing100 ppm F^- in female rats respectively. Serotonin content and turnover rate in...The animal models of subacute and chronic fluorosis were devel-oped with injection of large doses of NaF (IP)and drinking water containing100 ppm F^- in female rats respectively. Serotonin content and turnover rate inhypothalamus of rat were determined with spectrofluorometry combined degra-dation blockade. 5-HT turnover rate in hypothalamus decreased during bothsubacute and chronic fluorosis. 5-HT content in hypothalamus increased duringsubacute fluorosis, but decreased during chronic fluorosis. These results suggestthat the influences on 5-HT metabolism of two kinds of fluorosis are not com-pletely identical. The decrease of 5-HT turnover rate in hypothalamus may be one of thepossible mechanisms of deficiency of pituitary prolactin and milk secretion dur-ing fluorosis.展开更多
There is increasing evidence that stress can activate the hypothalamic-pituitary-adrenal-axis and hypothalamic-pituitary- thyroid-axis, and further affect the synthesis and secretion of corticotrophin-releasing hormo...There is increasing evidence that stress can activate the hypothalamic-pituitary-adrenal-axis and hypothalamic-pituitary- thyroid-axis, and further affect the synthesis and secretion of corticotrophin-releasing hormone （CRH） and thyrotropin-releasing hormone （TRH）. To evaluate the effect of cold stress on the hypothalamic CRH and TRH messenger RNA （mRNA） levels in Yisha chickens, male Yisha chickens were subjected to acute （1, 6, 12 h） and chronic （5, 10, 20 d） cold stress （12±1）℃. Hypothalami were collected for assessment of mRNA levels by semi-quantitative RT-PCR. Acute stress resulted in a significant decrease of CRH mRNA levels at 6 and 12 h, and a significant increase of TRH mRNA levels at every stress time point. Chronic cold stress resulted in a significant increase of CRH mRNA levels and a significant decrease of TRH mRNA levels compared with the control group at every stress time point. The results suggest that the two genes differently respond to cold stress at the mRNA levels. And the different degrees of cold stress will produce different effects on the identical gene.展开更多
基金The Project Supported by National Natural Science Foundation of China
文摘The animal models of subacute and chronic fluorosis were devel-oped with injection of large doses of NaF (IP)and drinking water containing100 ppm F^- in female rats respectively. Serotonin content and turnover rate inhypothalamus of rat were determined with spectrofluorometry combined degra-dation blockade. 5-HT turnover rate in hypothalamus decreased during bothsubacute and chronic fluorosis. 5-HT content in hypothalamus increased duringsubacute fluorosis, but decreased during chronic fluorosis. These results suggestthat the influences on 5-HT metabolism of two kinds of fluorosis are not com-pletely identical. The decrease of 5-HT turnover rate in hypothalamus may be one of thepossible mechanisms of deficiency of pituitary prolactin and milk secretion dur-ing fluorosis.
文摘There is increasing evidence that stress can activate the hypothalamic-pituitary-adrenal-axis and hypothalamic-pituitary- thyroid-axis, and further affect the synthesis and secretion of corticotrophin-releasing hormone （CRH） and thyrotropin-releasing hormone （TRH）. To evaluate the effect of cold stress on the hypothalamic CRH and TRH messenger RNA （mRNA） levels in Yisha chickens, male Yisha chickens were subjected to acute （1, 6, 12 h） and chronic （5, 10, 20 d） cold stress （12±1）℃. Hypothalami were collected for assessment of mRNA levels by semi-quantitative RT-PCR. Acute stress resulted in a significant decrease of CRH mRNA levels at 6 and 12 h, and a significant increase of TRH mRNA levels at every stress time point. Chronic cold stress resulted in a significant increase of CRH mRNA levels and a significant decrease of TRH mRNA levels compared with the control group at every stress time point. The results suggest that the two genes differently respond to cold stress at the mRNA levels. And the different degrees of cold stress will produce different effects on the identical gene.
