||Human Homo sapiens
||Lemons JM et al., Quiescent fibroblasts exhibit high metabolic activity. PLoS Biol. 2010 Oct 19 8(10):e1000514. doi: 10.1371/journal.pbio.1000514. p.10 right column bottom paragraphPubMed ID21049082
||"[Investigators] developed a model system that allows [them] to monitor
metabolic differences between proliferating and quiescent cells.
Primary dermal fibroblasts were expanded and analyzed while
actively proliferating, after 1 wk of growth to confluence (contact-inhibited
for 7 d [CI7]), after 2 wk of confluence (contact-inhibited
for 14 d [CI14]), or after 2 wk of confluence with serum
concentrations decreased for the final week from 10% to 0.1%
(contact-inhibited for 14 d and serum-starved for 7 d [CI14SS7]). Alternatively, fibroblasts were plated sparsely so that they did not
touch each other and induced into quiescence by serum starvation
and monitored after 4 d (serum-starved for 4 d [SS4]) or 7 d
(serum-starved for 7 d [SS7])."
||"Protein synthesis rates in the best-fit model
are 3.3 nmol/min/µg protein for proliferating fibroblasts,
4.3 nmol/min/µg protein for CI7 fibroblasts, 4.1 nmol/min/µg
protein for CI14 fibroblasts, and 2.9 nmol/min/µg protein for
CI14SS7 fibroblasts. Thus, one reason for the active metabolism
observed in contact-inhibited fibroblasts may be to rebuild and
thus refresh their lipid and protein contents."