ESSENTIALITY OF INSULIN FOR THE ACCUMULATION OF RAT MILK PROTEIN MRNA'S

胰岛素对于大鼠乳蛋白 mRNA 积累的重要性

• 批准号: 4691827
• 负责人: P K QASBA
• 金额: --
• 依托单位: DIVISION OF CANCER BIOLOGY AND DIAGNOSIS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/4691827
• 关键词: cell differentiation; cortisol; gene expression; growth factor; hormone regulation /control mechanism; insulin; messenger RNA; milk; tissue /cell culture

The control of overt differentiation of mammary gland in vitro involves an interplay between polypeptide and steroid hormones. Insulin, hydrocortisone and prolactin are absolutely required for the expression of milk protein genes. Role of individual hormones is being studied. These studies have shown: 1) In the presence of glucocorticoid and prolactin insulin is absolutely required for the expression of milk protein genes. In the present study it was shown that the accumulation effect on the 25K rat casein mRNA does not reflect stabilization of the transcript by insulin. Rather, insulin is essential for its synthesis in the presence of glucocorticoid and prolactin. Thus, insulin can be considered as a developmental hormone in the mammary system. Neither fetal calf serum nor Multiplication stimulating activity (MSA) or epidermal growth factor (EGF) can substitute insulin effect on differentation, though these hormones can sustain mammary cell vability in culture. 2) There is absolute requirement of hydrocortisone for accumulation of these messages, specifically the accumulation of 42K casein mRNA in mammary tissue from adrenalectomized, virgin rat is almost 20x higher in the presence of exogenous hydrocortisone than in its absence. Accumulation of 25K casein mRNA is also totally dependent on the steroid.

控制体外乳腺的明显分化， 多肽和类固醇激素之间相互作用。 胰岛素， 氢化可的松和催乳素是表达 乳蛋白基因 个别激素的作用正在研究中。 这些 研究表明：1）在糖皮质激素和催乳素的存在下， 胰岛素对于乳蛋白基因的表达是绝对必需的。 在本研究中，它表明，积累效应的25 K 大鼠酪蛋白mRNA不反映转录物的稳定性， 胰岛素 相反，胰岛素对于其在存在下的合成是必需的。 糖皮质激素和催乳素。 因此，胰岛素可以被认为是 乳腺系统中的发育激素。 胎牛血清和 增殖刺激活性（MSA）或表皮生长因子（EGF） 虽然这些激素可以替代胰岛素对分化的作用， 维持培养中乳腺细胞活力。 2)有绝对 需要氢化可的松来积累这些信息， 特别是42K酪蛋白mRNA在乳腺组织中的积累 肾上腺切除，处女大鼠几乎是20倍，在存在 外源性氢化可的松比在它的缺席。 25K酪蛋白的积累 mRNA也完全依赖于类固醇。