Somatomedin-like bioactivities of a growth hormone fragment on embryonic chick cartilage and cultured human fibroblasts.
Somatomedins are growth hormone-dependent peptides which appear to mediate many of the effects of growth hormone in vivo. These peptides are commonly assayed by their enhancement of proteoglycan sulfation in cartilage (or fibroblasts). We now report that fragment A-II (bovine growth hormone, 96--133) stimulates sulfation in chick embryonic cartilage and cultured fibroblasts. Enhancement of fibroblast proteoglycan sulfation by fragment A-II was log-dose dependent with maximal stimulation at 10(-8) M. The 25--100% maximal enhancement by fragment A-II was similar to that reported with a preparation of somatomedin A (Wasteson, A., Uthne, K., Westermark, B. (1973) Biochem. J. 136, 1069--1074). Sulfation of chick cartilage, in the presence of both serum (hypopituitary human) and fragment A-II was greater than the sum of the effects of each substance tested separately. Fragment A-II was tested between 10(-12) and 10(-8) M; maximal stimulation occurred at 5 . 10(-11) M. To our knowledge, no other growth hormone fragment has yet been shown to possess these somatomedin-like bioactivities. Our results suggest that fragment A-II may be very useful as a model peptide to study the actions and mechanism of naturally occurring sometomedins.
D000818:Animals; D002356:Cartilage / Q000187:drug effects / Q000378:metabolism*; D002642:Chick Embryo; D011508:Chondroitin Sulfate Proteoglycans / Q000096:biosynthesis; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D013006:Growth Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D008954:Models, Biological; D010446:Peptide Fragments / Q000494:pharmacology; D011134:Polysaccharides / Q000378:metabolism; D013002:Somatomedins / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism
D011508:Chondroitin Sulfate Proteoglycans; D010446:Peptide Fragments; D011134:Polysaccharides; D013002:Somatomedins; D013431:Sulfates; D013006:Growth Hormone