title: Interaction of multiplication stimulating activity/rat insulin-like growth factor II with skeletal muscle satellite cells during aging.
abstract: Satellite cells were isolated from the skeletal muscle of 3-, 12- and 24-month-old Fischer 344 rats. In vitro growth of these cells was evaluated in serum-containing medium and in serum-free medium in response to multiplication stimulating activity/rat insulin-like growth factor II (MSA). Cells from 3-month-old rats exhibited a shorter lag phase of growth than cells from 12- or 24-month-old animals. Dose-response curves for MSA with each of the three age groups did not differ in the concentrations of MSA required for a half-maximal response or in the magnitudes of the response. Hormone-binding data using [125I]MSA, however, revealed the highest numbers of MSA-binding sites with lowest affinities in the 3-month-old rat muscle cells; cells from the 24-month-old rats were intermediate and cells from the 12-month-old rats had the highest affinity and lowest number of binding sites. The lower affinity and increased number of binding sites in the young rat cells may be due to greater numbers of IGF type I receptors in muscle from young growing rats.
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D007335:Insulin-Like Growth Factor II / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D009132:Muscles / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D013002:Somatomedins / Q000494:pharmacology*
chemical_list: D013002:Somatomedins; D007335:Insulin-Like Growth Factor II