Zwierzchowski L, Kleczkowska D, Niedbalski W, Grochowska I
Differentiation. 1984;28(2):179-85. doi: 10.1111/j.1432-0436.1984.tb00281.x.
The rate of DNA synthesis and the activity of DNA polymerases and thymidine kinase were measured during the endocrine-regulated cellular growth and differentiation of mouse mammary gland. Using specific assays, the activity of the DNA polymerases, alpha, beta and gamma, was determined in tissue extracts of mammary glands of mice at various stages of pregnancy and early lactation. In addition, extracts of the mammary tissue of virgin, mid-pregnant and early lactating mice were fractionated on sucrose density gradients, and the activity of DNA polymerase alpha and beta was assayed in the gradient fractions. It was demonstrated that the activity of DNA polymerase alpha varied considerably during pregnancy and after parturition, showing peaks on day 12 of pregnancy and days 3-4 of lactation. In pregnancy, there was an apparently parallel correlation between the amount of DNA-polymerase-alpha activity and the rate at which the cells incorporated labelled thymidine into DNA, but the relationship was less clearly expressed during early lactation. The activity of the DNA polymerases, beta and gamma, as well as that of thymidine kinase showed little variation during these periods. Thus, in the developing mammary gland, no correlation was found between DNA synthesis and the activity of the DNA polymerases, beta and gamma, or thymidine kinase.
在小鼠乳腺内分泌调节的细胞生长和分化过程中，对DNA合成速率以及DNA聚合酶和胸苷激酶的活性进行了测定。采用特定检测方法，测定了处于妊娠和泌乳早期不同阶段的小鼠乳腺组织提取物中DNA聚合酶α、β和γ的活性。此外，对未孕、妊娠中期和泌乳早期小鼠的乳腺组织提取物进行蔗糖密度梯度分级分离，并对梯度级分中的DNA聚合酶α和β活性进行检测。结果表明，DNA聚合酶α的活性在妊娠期间和分娩后有很大变化，在妊娠第12天和泌乳第3 - 4天出现峰值。在妊娠期间，DNA聚合酶α活性的量与细胞将标记的胸苷掺入DNA的速率之间存在明显的平行相关性，但在泌乳早期这种关系不太明显。DNA聚合酶β和γ以及胸苷激酶的活性在这些时期变化很小。因此，在发育中的乳腺中，未发现DNA合成与DNA聚合酶β和γ或胸苷激酶的活性之间存在相关性。
