Effect of prolactin, progesterone, pregnancy and lactation on DNA synthesis and DNA polymerase activities in rabbit mammary gland.
DNA synthesis and DNA polymerase-alpha, -beta and -gamma activities in the rabbit mammary gland were studied during hormone-directed cellular growth. It was found that during pregnancy, early lactation and after injection of prolactin, changes in the activity of DNA polymerase-alpha paralleled the rate of mammary gland DNA synthesis. It was also found that the amount of polymerase-alpha activity bound to isolated chromatin depended on the physiological state of the animal. During pregnancy and early lactation changes in the activity of chromatin-bound enzyme correlated directly with the rate of DNA synthesis (r = 0.83). Moreover, in virgin rabbits treated with prolactin the activity of chromatin-bound DNA polymerase-alpha increased markedly at the same time as the DNA-synthetic rate increased. No correlation of the DNA-synthetic rate was found with the activity of soluble (cytosolic) DNA polymerase-alpha or with the activity of soluble or chromatin-bound DNA polymerases-beta and -gamma. On the basis of these results it is suggested that in the developing mammary gland both the activity and cellular distribution of DNA polymerase-alpha might be subject to hormonal regulation.
Zwierzchowski
L
L
Department of Biochemistry, Polish Academy of Sciences, Mroków.
Niedbalski
W
W
Kleczkowska
D
D
D000818:Animals; D004247:DNA / Q000096:biosynthesis*; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D004256:DNA Polymerase I / Q000378:metabolism; D004257:DNA Polymerase II / Q000378:metabolism; D005260:Female; D007774:Lactation / Q000187:drug effects; D008321:Mammary Glands, Animal / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D011374:Progesterone / Q000494:pharmacology; D011388:Prolactin / Q000494:pharmacology; D011817:Rabbits
D011374:Progesterone; D011388:Prolactin; D004247:DNA; D004254:DNA Nucleotidyltransferases; D004256:DNA Polymerase I; D004257:DNA Polymerase II