Stretch-induced prostaglandins and protein turnover in cultured skeletal muscle.
Intermittent repetitive mechanical stimulation of differentiated avian skeletal muscle cells in vitro for 48 h stimulates skeletal muscle growth [Am. J. Physiol. 256 (Cell Physiol. 25): C674-C682, 1989]. During the first 2-3 h of stimulation, temporary muscle damage occurs based on increases in creatine kinase efflux, total protein degradation rates, and several proteinase activites. With continued mechanical stimulation for several days in serum-containing medium, the proteinase activities return to control levels, and total protein degradation rates decrease to levels less than static controls. Decreased protein degradation thus contributes to stretch-induced cell growth. The efflux of prostaglandins (PG) E2 and F2 alpha but not 6-keto-PGF1 alpha increase with mechanical stimulation. During the first 5 h of stimulation, PGE2 and PGF2 alpha efflux rates increase 101 and 41%, respectively. PGE2 efflux returns to control levels by 24 h of mechanical stimulation, whereas PGF2 alpha efflux is continuously elevated (41-116%) for at least 48 h. The long-term stretch-induced elevation of PGF2 alpha efflux correlates with a 52-98% long-term increase in total protein synthesis rates. The prostaglandin synthesis inhibitor indomethacin partially blocks early stretch-induced cell damage and long-term stretch-induced cell growth. The results indicate that both of these processes are partially dependent on stretch-induced increases in prostaglandin synthesis.
Vandenburgh
H H
HH
Department of Pathology, Brown University, Providence, Rhode Island.
Hatfaludy
S
S
Sohar
I
I
Shansky
J
J
D000818:Animals; D002403:Cathepsins / Q000378:metabolism*; D002478:Cells, Cultured; D002642:Chick Embryo; D015237:Dinoprost / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D007700:Kinetics; D008666:Metalloendopeptidases / Q000378:metabolism*; D009119:Muscle Contraction; D009132:Muscles / Q000187:drug effects / Q000502:physiology*; D010812:Physical Stimulation; D011453:Prostaglandins / Q000378:metabolism*; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism*
D011453:Prostaglandins; D011506:Proteins; D015237:Dinoprost; D002403:Cathepsins; D008666:Metalloendopeptidases; D015232:Dinoprostone; D007213:Indomethacin