Late G1 amino acid restriction point in human dermal fibroblasts.
Human dermal fibroblasts arrested in G0 by maintenance in medium supplemented with 0.1% serum were not restimulated to divide when fresh medium containing 10% dialyzed serum but lacking group B amino acids (cystine, isoleucine, lysine, phenylalanine and tyrosine) was added. Unlike rodent cells, the addition of fresh serum-supplemented medium lacking only isoleucine did not cause a growth arrest. The amino acid sensitive growth arrest in human fibroblasts was dependent both on presynchronization in G0 as well as a prestarvation for amino acids prior to stimulation with high serum. When cells were restimulated in the absence of amino acids, they arrested predominantly in G1, although a small percentage of cells entered early S phase. When medium containing a complete complement of amino acids was then added, cells initiated DNA synthesis following a minimum lag of 2-3 hr. Growth arrested cells initiated DNA synthesis even when complete unsupplemented medium was added, although the addition of high concentrations of insulin or 10% serum increased the rate of entry.
D000596:Amino Acids / Q000502:physiology*; D000818:Animals; D001769:Blood; D002455:Cell Division; D005347:Fibroblasts / Q000166:cytology; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D007399:Interphase; D007532:Isoleucine / Q000502:physiology; D007700:Kinetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012867:Skin / Q000166:cytology*
D000596:Amino Acids; D007328:Insulin; D007532:Isoleucine