Further characterization of the keratinocyte somatomedin-C/insulin-like growth factor I (SM-C/IGF-I) receptor and the biological responsiveness of cultured keratinocytes to SM-C/IGF-I.
Somatomedin-C/insulin-like growth factor I (SM-C/IGF-I) binds to both cultured keratinocytes trypsinized to single-cell suspensions and fresh epidermal sheets derived from 1 M NaBr-treated 6-mm punch biopsies. A gradual increase of 1-4% in specific binding of SM-C/IGF-I to fresh epidermal sheets was observed during a 5-hour incubation period at 15 degrees C. The human keratinocyte SM-C/IGF-I receptor was isolated by polyacrylamide gel electrophoresis after cross-linking with iodinated SM-C/IGF-I and migrated at 135,000 daltons under reducing conditions. Both a partially purified preparation of SM-C/IGF-I, as well as recombinant DNA-derived thr-59-SM-C/IGF-I (25-100 ng/ml), stimulated keratinocyte replication in a serum-free system, with an approximately equivalent effect as insulin (10 micrograms/ml). Since fibroblasts produce SM-C/IGF-I, our data suggest that some dermal-epidermal interactions in diseases such as psoriasis may be mediated, in part, by SM-C/IGF-I.
Nickoloff
B J
BJ
Department of Dermatology, Stanford University School of Medicine, Calif.
Misra
P
P
Morhenn
V B
VB
Hintz
R L
RL
Rosenfeld
R G
RG
D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004274:DNA, Recombinant / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D000078404:Epidermal Cells; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology*; D007633:Keratins / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000302:isolation & purification / Q000378:metabolism*; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000378:metabolism* / Q000494:pharmacology*; D013997:Time Factors; D014357:Trypsin / Q000494:pharmacology
D004274:DNA, Recombinant; D007328:Insulin; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007633:Keratins; D003907:Dexamethasone; D014357:Trypsin