Golden K L, Rillema J A
Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
Proc Soc Exp Biol Med. 1995 Sep;209(4):392-6. doi: 10.3181/00379727-209-43913.
Studies were carried out to determine the possible mechanism(s) by which prolactin (PRL) stimulates alpha-lactalbumin and galactosyl transferase activity in cultured mouse mammary tissues. In earlier studies it was shown that the onset of the PRL stimulation of galactosyl transferase activity occurs between 4 and 8 hr after adding prolactin to cultured mouse mammary gland explants, and a maximum effect is evoked by 24 hr. In contrast, an effect of prolactin on alpha-lactalbumin activity occurred 24 hr after adding PRL to mammary gland cultures, but not at earlier times. In the present studies, it is shown that prolactin effects an increased tissue accumulation of mRNAs for both alpha-lactalbumin and galactosyl transferase after a 4 to 6 hr culture with prolactin. The lowest concentration of prolactin that stimulates the accumulation of both galactosyl transferase and alpha-lactalbumin mRNA is approximately 10 ng/ml, and a maximum response is achieved with 200 ng/ml. Thus, it is likely that the effect of PRL on the activity of galactosyl transferase is causally associated with the effect of prolactin on the accumulation of its mRNAs. However, the PRL stimulation of alpha-lactalbumin activity is not temporally associated with the tissue accumulation of the mRNA for alpha-lactalbumin.
开展了多项研究以确定催乳素（PRL）刺激培养的小鼠乳腺组织中α-乳白蛋白和半乳糖基转移酶活性的可能机制。在早期研究中发现，向培养的小鼠乳腺外植体中添加催乳素后，催乳素刺激半乳糖基转移酶活性的起始时间在4至8小时之间，24小时时可诱发最大效应。相比之下，向乳腺培养物中添加催乳素24小时后，催乳素对α-乳白蛋白活性产生影响，但在更早的时间则无此作用。在本研究中发现，用催乳素培养4至6小时后，催乳素会使α-乳白蛋白和半乳糖基转移酶的mRNA在组织中的积累增加。刺激半乳糖基转移酶和α-乳白蛋白mRNA积累的最低催乳素浓度约为10 ng/ml，200 ng/ml时可达到最大反应。因此，催乳素对半乳糖基转移酶活性的影响可能与其对mRNA积累的影响存在因果关系。然而，催乳素对α-乳白蛋白活性的刺激与α-乳白蛋白mRNA在组织中的积累在时间上并无关联。
