Accumulation of pyrroline 5-carboxylic acid in conditioned medium of cultured fibroblast: stimulatory effects of serum, insulin, and IGF-1.
Pyrroline 5-carboxylate, an intermediate of amino acid metabolism, is released into medium by cultured normal human fibroblasts. With cells made quiescent by serum starvation, the addition of 10% fetal bovine serum augmented the release of pyrroline 5-carboxylate into medium by 2.5-fold. Although platelet-derived growth factor was without effect, both insulin and insulinlike growth factor-1 nearly reproduced the serum effect. The dose-dependence of insulin and insulinlike growth factor 1 effects suggested their mediation by their own respective receptors. Although the mechanism for the stimulatory effect remains unknown, these effects of insulin and insulinlike growth factor 1 on pyrroline 5-carboxylate suggest hormonal regulation of pyrroline 5-carboxylate release.
Laboratory of Nutritional and Molecular Regulation, National Cancer Institute, Frederick Cancer Research and Development Center, Maryland 21702.
B A
BA
Semon
J M
JM
Phang
D001769:Blood; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007700:Kinetics; D011758:Pyrroles / Q000378:metabolism*; D012867:Skin / Q000187:drug effects / Q000378:metabolism
D016895:Culture Media, Serum-Free; D007328:Insulin; D011758:Pyrroles; C015485:delta-1-pyrroline-5-carboxylate; D007334:Insulin-Like Growth Factor I