[Pregnancy induced DNA synthesis in parenchymatous organs of the rat. Autoradiographic investigations following permanent infusion of 3H-thymidine (author's transl)].
Autoradiographic investigations, after permanent infusion of 3H-thymidine during the whole course of pregnancy in 3 to 5 months old white Spraque-Dawley rats of 220-305 g body weight demonstrate an enhanced DNA synthesis in all cell systems tested. 1. In the liver the mean value of the proliferation index in the hepatocytes increases from a control value of 0.7% to 10.4%, in the epithelia of the portal ducts from 6.7% to 42.4% and in the sinus cells from 3.7% to 23.9% at the end of pregnancy. The corresponding values in the pancreas run up to 6.3% (3.4%) in the acinus parenchyma and 19.6% (8.8%) in the islet cells of Langerhans. In the duct epithelia no significant increase of labelled cells can be found. In the kidney, the number of DNA synthesizing tubular cells depends on their localization within the nephron: in the epithelia of the proximal tubulus the proliferation index amounts to 2.7% (0.6%), in that of the distal tubulus to 4.5% (1.4%). The highest percentual increase in comparison with the control animals results in the proximal tubular epithelia of pregnant rats. The cells of the glomerula are practically uninvolved. 2. The enhanced proliferation may rest on the influence of hypophysial or placental hormones--especially of somatotropins--as well as on an intensified function of the organs during pregnancy. Both hormonal and functional stimuli are closely mixed up in their significance for the pregnancy-induced DNA syntheses, accordingly their effect cannot be separated exactly. The hormones seemingly represent the inducing factor for the increased DNA syntheses during pregnancy which is realized in a variable amount within the organs depending on their different functional enhancement. 3. The increase of the proliferation indices ranges considerably from individual to individual, but within one single animal all cellular systems are afflicted in the same way. The individual ranges of the proliferation rates within the organs are directly proportional to the weight of the offsprings and indirectly proportional to the weight of the mother. The only exception of this is in the proximal tubular epithelium of the kidney. The important influence of adaptation drocesses to the enhanced function of an organ during pregnancy is emphasized by this fact.
D000818:Animals; D001345:Autoradiography; D001835:Body Weight; D002455:Cell Division; D004247:DNA / Q000096:biosynthesis*; D005260:Female; D007515:Islets of Langerhans / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D007686:Kidney Tubules, Distal / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D010179:Pancreas / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats
D004247:DNA
Schwangerschaftsabhängige DNS-Synthesen in parenchymatösen Organen der Ratte. Autoradiographische Untersuchungen nach 3H-Thymidin-Dauerinfusion