Somatomedin-C/insulin-like growth factor-I and Insulin-like growth factor-II mRNAs in rate fetal and adult tissues
Somatomedin-C or insulin-like growth factor I (Sm-C/IGF-I) and insulin-like growth factor II (IGF-II) have been implicated in the regulation of fetal growth and development. In the present study /sup 32/P-labeled complementary DNA probes encoding human and mouse Sm-C/IGF-I and human IGF-II were used in Northern blot hybridizations to analyze rat Sm-C/IGF-I and IGF-II mRNAs in poly(A/sup +/) RNAs from intestine, liver, lung, and brain of adult rats and fetal rats between day 14 and 17 of gestation. In fetal rats, all four tissues contained a major mRNA of 1.7 kilobase (kb) that hybridized with the human Sm-C/IGF-I cDNA and mRNAs of 7.5, 4.7, 1.7, and 1.2 kb that hybridized with the mouse Sm-C/IGF-I cDNA. Adult rat intestine, liver, and lung also contained these mRNAs but Sm-C/IGF-I mRNAs were not detected in adult rat brain. These findings provide direct support for prior observations that multiple tissues in the fetus synthesize immunoreactive Sm-C/IGF-I and imply a role for Sm-C/IGF-I in fetal development as well as postnatally. Multiple IGF-II mRNAs of estimated sizes 4.7, 3.9, 2.2, 1.75, and 1.2 kb were observed in fetal rat intestine, liver, lung, and brain. The 4.7- and 3.9-kb mRNAs were the major hybridizing IGF-II mRNAs in all fetal tissues. Higher abundance of IGF-II mRNAs in rat fetal tissues compared with adult tissues supports prior hypotheses, based on serum IGF-II concentrations, that IGF-II is predominantly a fetal somatomedin. IGF-II mRNAs are present, however, in some poly(A/sup +/) RNAs from adult rat tissues. The brain was the only tissue in the adult rat where the 4.7- and 3.9-kb IGF-II mRNAs were consistently detected. These findings suggest that a role for IGF-II in the adult rat, particularly in the central nervous system, cannot be excluded.
- Research Organization:
- Univ. of North Carolina, Chapel Hill
- OSTI ID:
- 7093617
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 261:31
- Country of Publication:
- United States
- Language:
- English
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MESSENGER-RNA
AUTORADIOGRAPHY
HYBRIDIZATION
PEPTIDES
BIOSYNTHESIS
PHOSPHORUS 32
TISSUE DISTRIBUTION
RECOMBINANT DNA
ADULTS
AGE DEPENDENCE
BRAIN
FETUSES
GROWTH
INSULIN
INTESTINES
LIVER
LUNGS
MOLECULAR STRUCTURE
ONTOGENESIS
RATS
AGE GROUPS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISTRIBUTION
DNA
GASTROINTESTINAL TRACT
GLANDS
HORMONES
ISOTOPES
LIGHT NUCLEI
MAMMALS
NERVOUS SYSTEM
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PHOSPHORUS ISOTOPES
PROTEINS
RADIOISOTOPES
RESPIRATORY SYSTEM
RNA
RODENTS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques