Primary structure of rat insulin-like growth factor-I and its biological activities.
Rat insulin-like growth factor-I (IGF-I), a serum polypeptide with growth promoting activity, was isolated from rat serum by a combination of acid/ethanol extraction, affinity chromatography, and a series of reversed phase high performance liquid chromatography, cation exchange, and reversed phase. All peptide fragments produced by chymotrypsin digestion of reduced and carboxymethylated rat IGF-I were amino acid sequenced and compared with the sequence of human IGF-I. Three out of 70 of the rat amino acid residues differed from those of human IGF-I as follows: Asp20----Pro, Ser35----Ile and Ala67----Thr. Purified rat IGF-I cross-reacted with polyclonal anti-human IGF-I antibody 75% as compared to human IGF-I, but it cross-reacted only 3% with monoclonal anti-human IGF-I antibody. Thus, it is possible to monitor the metabolic fate of human IGF-I, when injected into rats, without interference by endogenous rat IGF-I. Rat IGF-I showed 65% activity in the radioreceptor, 28.6% activity in the lipogenesis and 22.5% activity in the free fatty acid release inhibition assays as compared to human IGF-I on a protein quantity basis.
Tamura
K
K
Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., Osaka, Japan.
Kobayashi
M
M
Ishii
Y
Y
Tamura
T
T
Hashimoto
K
K
Nakamura
S
S
Niwa
M
M
Zapf
J
J
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D003429:Cross Reactions; D004261:DNA Replication / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics* / Q000302:isolation & purification / Q000494:pharmacology; D007700:Kinetics; D008055:Lipids / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism; D017451:Receptors, Somatomedin; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000494:pharmacology; D013002:Somatomedins / Q000235:genetics*; D013045:Species Specificity
D005230:Fatty Acids, Nonesterified; D008055:Lipids; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D011994:Recombinant Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D005947:Glucose