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Measurement of Somatomedin-Related Peptides in Fetal, Neonatal, and Maternal Rat Serum by Insulin-Like Growth Factor (IGF) I Radioimmunoassay, IGF-II Radioreceptor Assay (RRA), and Multiplication- Stimulating Activity RRA after Acid-Ethanol Extraction*
Abstract
Previous measurements of somatomedins (Sms) and insulin-like growth factors (IGFs) in maternal and fetal serum have yielded contradictory results. We have, therefore, measured maternal, fetal, and neonatal rat serum with two highly specific assays: 1) IGF-I/Sm-C RiA and 2) a highly specific IGF-II/rat placental membrane radioreceptor assay (RRA). In addition, we have made measurements with a less specific multiplication-stimulating activity (MSA)-rat placental membrane RRA. To avoid possible serious artifacts created by Sm-binding proteins, preliminary acid-ethanol extraction of serum was performed. Results are expressed in terms of a reference human serum with an assigned potency of 1 U/ml. Maternal RIA IGF-I fluctuated between 1.1-1.4 U/ml from the 17th day of pregnancy to the 25th day after delivery (nonpregnant rat serum pool, 1.25 +/- 0.22 U/ml). On day 21 of gestation, fetal serum radioimmunoassayable IGF-I was 1.03 +/- 0.03 U/ml. After birth, radioimmunoassayable IGF-I fell and reached .19 +/- 0.03 U/ml at 18 days of age, but rose to 0.71 +/- 0.04 U/ml at 25 days of age. At term, maternal radioreceptor assayable IGF-II was 2.18 +/- 0.27 U/ml (nonpregnant female pool, 1.4 +/- 0.12). By the 25th postpartum day, radioreceptor assayable IGF-II was 1.39 +/- 0.12 U/ml. Radioreceptor assayable IGF-II in fetal serum on day 19 was 3.26 +/- 0.48 U/ml and rose to 5.37 +/- 0.66 U/ml on the day of delivery. A further rise to 8.92 +/- 1.03 occurred on day 5. A subsequent fall to 2.41 +/- 0.05 U/ml was observed on day 25. The patterns of results of the MSA RRA in fetal and neonatal rat serum were similar to that obtained with the IGF-II RRA. We now conclude that radioimmunoassayable IGF-I is present in higher concentrations than previously reported in term fetal rat serum and that radioreceptor assayable IGF-II is selectively elevated in rat fetal and neonatal life and may have unique metabolic and growth-promoting significance.U
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Brown, A. L., Graham, D. E., Nissley, S. P., Hill, D. J., Strain, A. J., & Rechler, M. M. (1986) · Journal of Biological Chemistry · doi:10.1016/s0021-9258(18)69282-8 · Cited by 321
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Metadata
- Authors
- DAUGHADAY, W. H., PARKER, K. A., BOROWSKY, S., TRIVEDI, B., & KAPADIA, M.
- Venue
- Endocrinology
- Publisher
- The Endocrine Society
- Published
- 1982-02
- Volume
- 110
- Issue
- 2
- Pages
- 575-581
- ISSN
- 0013-7227 (ISSN-L)
- 1945-7170
- OpenAlex
- W2090015237
- Cited by
- 270
- References
- 0
- FWCI
- 14.05
- Type
- journal article
- Language
- en
- Open access
- closed
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- CoChat. (2026). Citation check: Measurement of Somatomedin-Related Peptides in Fetal, Neonatal, and Maternal Rat Serum by Insulin-Like Growth Factor (IGF) I Radioimmunoassay, IGF-II Radioreceptor Assay (RRA), and Multiplication- Stimulating Activity RRA after Acid-Ethanol Extraction*. https://app.cochat.ai/papers/10.1210/endo-110-2-575
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- DAUGHADAY, W. H., PARKER, K. A., BOROWSKY, S., TRIVEDI, B., & KAPADIA, M. (1982). Measurement of Somatomedin-Related Peptides in Fetal, Neonatal, and Maternal Rat Serum by Insulin-Like Growth Factor (IGF) I Radioimmunoassay, IGF-II Radioreceptor Assay (RRA), and Multiplication- Stimulating Activity RRA after Acid-Ethanol Extraction*. Endocrinology. https://doi.org/10.1210/endo-110-2-575
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