Insulin responsiveness of a mouse mammary adenocarcinoma culture in the expression of two proliferation-derived cytoplasmic proteins.
Insulin induced in organ culture of a mouse mammary adenocarcinoma the expression of two cytoplasmic proteins of molecular size 72 and 49 kD. In freshly excised tumor both proteins are present in relatively large amounts, but their concentration became greatly diminished during culture in insulin-free media, indicating sensitivity to post-transcriptional modification which was activated in vitro in the absence of insulin. In insulin cultures the two proteins reappeared after two culture days, their concentration becoming increased thereafter with time of culture, but their expression could not be correlated with the biphasic pattern of transcriptional activity fluctuation recorded during culture similarly to insulin-free cultures. Insulin on the other hand stimulated two waves of doubling of DNA synthesis during 6 culture days. The results demonstrate insulin responsiveness in culture of a proliferative fraction of the tumorous cell population in this adenocarcinoma line in the synthesis of two sensitive proliferation-derived cytoplasmic proteins. The possible biological significance of these proteins is discussed.
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D000230:Adenocarcinoma / Q000378:metabolism*; D000818:Animals; D003208:Concanavalin A / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D004273:DNA, Neoplasm / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D009363:Neoplasm Proteins / Q000378:metabolism*; D009924:Organ Culture Techniques; D010316:Particle Size; D012313:RNA / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic
D004273:DNA, Neoplasm; D007328:Insulin; D009363:Neoplasm Proteins; D003208:Concanavalin A; D012313:RNA