乳腺发育及泌乳是由机体内分泌系统严格控制的复杂过程,受多种激素和细胞因子等因素的调控,许多外源激素和生长因子对乳腺生长发育、泌乳的启动和维持具有十分重要的调节作用。而具有促进细胞分化和增殖作用的类胰岛素样生长因子-Ⅰ(ins...乳腺发育及泌乳是由机体内分泌系统严格控制的复杂过程,受多种激素和细胞因子等因素的调控,许多外源激素和生长因子对乳腺生长发育、泌乳的启动和维持具有十分重要的调节作用。而具有促进细胞分化和增殖作用的类胰岛素样生长因子-Ⅰ(insulin like growth factors-Ⅰ,IGF-Ⅰ)在奶牛乳腺生长发育中起重要作用,IGF-Ⅰ可促进细胞生长分化和存活,从而维持泌乳细胞的数量和泌乳性能,可以说IGF-Ⅰ是促进泌乳和维持泌乳更直接的生长因子。近年来,IGF-Ⅰ对动物乳腺发育和泌乳性能的影响也成为研究热点之一,因此文章扼要叙述了IGF-Ⅰ及其受体对乳腺上皮细胞及泌乳等的影响和可能的作用机制。展开更多
Recombinant salmon growth hormone contained in yeast was given for 5 months to flounder in its diet. Both free and total specific binding sites for the growth hormone were examined in liver membranes of control and tr...Recombinant salmon growth hormone contained in yeast was given for 5 months to flounder in its diet. Both free and total specific binding sites for the growth hormone were examined in liver membranes of control and treated fish. The association constants of both free and total specific binding sites were of the same order (1 nM 1 ), and no significant difference was found between any two groups in the capacity of their free binding sites. The capacity of total binding sites in the liver of treated fish increased significantly compared with that of control. Insulin like growth factor I (IGF I) levels in the plasma of treated fish increased by 22.61% (P<0.05), compared with that of control. While the T 4 levels in plasma did not increase significantly (from 1.35±0.91 ng/ml to 2.29±1.13 ng/ml), T 3 levels were elevated significantly (from 1.78±1.14 ng/ml to 4.87±1.22 ng/ml, P<0.01), as compared with that of control.展开更多
Expression of mRNAs for IGF-I, IGF-binding protein-2 (IGFBP-2), and LH receptor (LHR) as well as their regulations during induced follicular atresia was determined. 26-day-old female rats received 15 IU pregnant mare ...Expression of mRNAs for IGF-I, IGF-binding protein-2 (IGFBP-2), and LH receptor (LHR) as well as their regulations during induced follicular atresia was determined. 26-day-old female rats received 15 IU pregnant mare serum gonadotropins (PMSG). Through detection, it was demonstrated that apoptosis occurred in some small antral follicles after 48 h of PMSG treatment. At 96 h, apoptosis occurred in preovulatory follicles. At 120 h, numerous apoptotic cells appeared in preovulatory follicles. IGF-I was mainly expressed in preantral and small antral follicles from 48 to 120 h. At 48 and 96 h, the theca cells of preantral and antral follicles expressed high level of IGFBP-2 mRNA. At 48 h, there were strong signals of LHR mRNA in granulosa cells, but the LHR signals in granulosa cells significantly decreased at 96 and 120 h (p<0.001). Both epidermal growth factor (EGF) and IGF-I inhibited apoptosis in preantral and antral follicles. Meanwhile, it was observed that EGF promoted IGF-I mRNA expression, and in preovulatory follicles, IGF-I stimulated LHR mRNA expression. These results show that the interaction between ECF and IGF-I may be involved in the regulation of atresia of follicles at different stages of development.展开更多
文摘乳腺发育及泌乳是由机体内分泌系统严格控制的复杂过程,受多种激素和细胞因子等因素的调控,许多外源激素和生长因子对乳腺生长发育、泌乳的启动和维持具有十分重要的调节作用。而具有促进细胞分化和增殖作用的类胰岛素样生长因子-Ⅰ(insulin like growth factors-Ⅰ,IGF-Ⅰ)在奶牛乳腺生长发育中起重要作用,IGF-Ⅰ可促进细胞生长分化和存活,从而维持泌乳细胞的数量和泌乳性能,可以说IGF-Ⅰ是促进泌乳和维持泌乳更直接的生长因子。近年来,IGF-Ⅰ对动物乳腺发育和泌乳性能的影响也成为研究热点之一,因此文章扼要叙述了IGF-Ⅰ及其受体对乳腺上皮细胞及泌乳等的影响和可能的作用机制。
基金NationalKeyProblemforthe"Ninth Five Year Plan" (96 C0 1 0 5 0 4)
文摘Recombinant salmon growth hormone contained in yeast was given for 5 months to flounder in its diet. Both free and total specific binding sites for the growth hormone were examined in liver membranes of control and treated fish. The association constants of both free and total specific binding sites were of the same order (1 nM 1 ), and no significant difference was found between any two groups in the capacity of their free binding sites. The capacity of total binding sites in the liver of treated fish increased significantly compared with that of control. Insulin like growth factor I (IGF I) levels in the plasma of treated fish increased by 22.61% (P<0.05), compared with that of control. While the T 4 levels in plasma did not increase significantly (from 1.35±0.91 ng/ml to 2.29±1.13 ng/ml), T 3 levels were elevated significantly (from 1.78±1.14 ng/ml to 4.87±1.22 ng/ml, P<0.01), as compared with that of control.
文摘Expression of mRNAs for IGF-I, IGF-binding protein-2 (IGFBP-2), and LH receptor (LHR) as well as their regulations during induced follicular atresia was determined. 26-day-old female rats received 15 IU pregnant mare serum gonadotropins (PMSG). Through detection, it was demonstrated that apoptosis occurred in some small antral follicles after 48 h of PMSG treatment. At 96 h, apoptosis occurred in preovulatory follicles. At 120 h, numerous apoptotic cells appeared in preovulatory follicles. IGF-I was mainly expressed in preantral and small antral follicles from 48 to 120 h. At 48 and 96 h, the theca cells of preantral and antral follicles expressed high level of IGFBP-2 mRNA. At 48 h, there were strong signals of LHR mRNA in granulosa cells, but the LHR signals in granulosa cells significantly decreased at 96 and 120 h (p<0.001). Both epidermal growth factor (EGF) and IGF-I inhibited apoptosis in preantral and antral follicles. Meanwhile, it was observed that EGF promoted IGF-I mRNA expression, and in preovulatory follicles, IGF-I stimulated LHR mRNA expression. These results show that the interaction between ECF and IGF-I may be involved in the regulation of atresia of follicles at different stages of development.
