Thirty-two Wistar rats were divided randomly into four groups of eight with six females and two males in each group. The rats were exposed to high fluoride drinking water (45 mg F- L-1 from 100 mg NaF L-1), low dietar...Thirty-two Wistar rats were divided randomly into four groups of eight with six females and two males in each group. The rats were exposed to high fluoride drinking water (45 mg F- L-1 from 100 mg NaF L-1), low dietary iodine (0.0855 mg kg-1), or both together in order to assess the effects of these three regimens on the thyroid function of the offspring rats. After the animal model was established, the offspring rats were bred and 10-, 20-, 30-, 60-, and 90-d-old rats were used for the experiment. The treatments for the offspring rats were the same as those of their parents. In comparison with control rats, the relative thyroid glands were changed by three regimens, but the mean values of thyroid weight in the experimental groups saw no marked difference. Serum TT3 levels were increased in all stages in the low iodine (LI) group. In the high fluoride (HiF) group, increase in TT3 levels was observed except in 20-d-old rats. Decrease in TT3 at 20- and 90-d and increase in TT3 at 30- and 60-d were found in HiF+LI group. Serum TT4 levels first saw an increase, and then dropped in the LI and HiF+LI group. However, an increase in TT4 was found in the HiF group. The levels of TSH in serum rocketed at d 20, and then dropped in the next stages in experimental groups. The results suggested that thyroid disorder could be induced by high flroride in drinking water, low iodine diet, or both of them. Exposure time to fluoride or low iodine diet was one of the important factors that fluoride can induce the development of thyroid dyfunction.展开更多
Orexin has several biological functions, including the regulation of reproductive endocrine signaling, which has received much attention. However, little is known about the mechanism through which orexin regulates the...Orexin has several biological functions, including the regulation of reproductive endocrine signaling, which has received much attention. However, little is known about the mechanism through which orexin regulates the levels of neuroendocrine hormones and peptides. We injected orexin A or physiological saline into the lateral ventricle of 10 ovariectomized (OVX) gilts, and determined the subsequent changes in serum luteinizing hormone (LH) concentration by using radioimmunoassay (RIA). We also examined the expression of GnRH, NPY, and POMC mRNAs in the hypothalamus and that of LH, follicle-stimulating hormone (FSH), POMC, and ghrelin mRNAs in the pituitary by using semi-quantitative reverse transcription polymerase chain reaction. We found the following results: (1) Orexin A transiently promoted LH secretion; serum LH concentration started to increase at 10 min after the orexin injection, peaked at 30 min, and returned to its initial level at 1.5 h; (2) orexin A upregulated GnRH mRNA expression and downregulated NPY and POMC mRNAs expression in the hypothalamus; (3) orexin A upregulated LH and FSH mRNAs expression (FSH, P > 0.05), but downregulated ghrelin mRNA expression in the pituitary. No significant effects were observed on the pituitary expression of FSH and POMC mRNAs. Our data suggest that orexin A regulates reproductive function by stimulating GnRH and LH release directly and indirectly via its effects on NPY, POMC and ghrelin expression.展开更多
基金sponsored by the National Natural Science Foundation of China (30170681)the Foundation of Henan Institute of Science and Technology, China(6007)
文摘Thirty-two Wistar rats were divided randomly into four groups of eight with six females and two males in each group. The rats were exposed to high fluoride drinking water (45 mg F- L-1 from 100 mg NaF L-1), low dietary iodine (0.0855 mg kg-1), or both together in order to assess the effects of these three regimens on the thyroid function of the offspring rats. After the animal model was established, the offspring rats were bred and 10-, 20-, 30-, 60-, and 90-d-old rats were used for the experiment. The treatments for the offspring rats were the same as those of their parents. In comparison with control rats, the relative thyroid glands were changed by three regimens, but the mean values of thyroid weight in the experimental groups saw no marked difference. Serum TT3 levels were increased in all stages in the low iodine (LI) group. In the high fluoride (HiF) group, increase in TT3 levels was observed except in 20-d-old rats. Decrease in TT3 at 20- and 90-d and increase in TT3 at 30- and 60-d were found in HiF+LI group. Serum TT4 levels first saw an increase, and then dropped in the LI and HiF+LI group. However, an increase in TT4 was found in the HiF group. The levels of TSH in serum rocketed at d 20, and then dropped in the next stages in experimental groups. The results suggested that thyroid disorder could be induced by high flroride in drinking water, low iodine diet, or both of them. Exposure time to fluoride or low iodine diet was one of the important factors that fluoride can induce the development of thyroid dyfunction.
基金sponsored by the National Natural Sci-ence Foundation of China (30471248)
文摘Orexin has several biological functions, including the regulation of reproductive endocrine signaling, which has received much attention. However, little is known about the mechanism through which orexin regulates the levels of neuroendocrine hormones and peptides. We injected orexin A or physiological saline into the lateral ventricle of 10 ovariectomized (OVX) gilts, and determined the subsequent changes in serum luteinizing hormone (LH) concentration by using radioimmunoassay (RIA). We also examined the expression of GnRH, NPY, and POMC mRNAs in the hypothalamus and that of LH, follicle-stimulating hormone (FSH), POMC, and ghrelin mRNAs in the pituitary by using semi-quantitative reverse transcription polymerase chain reaction. We found the following results: (1) Orexin A transiently promoted LH secretion; serum LH concentration started to increase at 10 min after the orexin injection, peaked at 30 min, and returned to its initial level at 1.5 h; (2) orexin A upregulated GnRH mRNA expression and downregulated NPY and POMC mRNAs expression in the hypothalamus; (3) orexin A upregulated LH and FSH mRNAs expression (FSH, P > 0.05), but downregulated ghrelin mRNA expression in the pituitary. No significant effects were observed on the pituitary expression of FSH and POMC mRNAs. Our data suggest that orexin A regulates reproductive function by stimulating GnRH and LH release directly and indirectly via its effects on NPY, POMC and ghrelin expression.
