Investigation into the potential physiological sources of rat milk IGF-I and IGF-binding proteins
| Autor: | R L Hintz, Sharon M. Donovan, Ron G. Rosenfeld |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
medicine.medical_specialty
Endocrinology Diabetes and Metabolism Mammary gland Chromosomal translocation Biology Breast milk Insulin-like growth factor-binding protein Iodine Radioisotopes Mammary Glands Animal Endocrinology Lactation Internal medicine medicine Animals RNA Messenger Insulin-Like Growth Factor I Rats Wistar Messenger RNA Blotting Northern Growth Inhibitors Rats Insulin-Like Growth Factor Binding Proteins De novo synthesis Blot Insulin-Like Growth Factor Binding Protein 2 Milk medicine.anatomical_structure Insulin-Like Growth Factor Binding Protein 4 Liver Chromatography Gel biology.protein Female Carrier Proteins |
| Zdroj: | Journal of Endocrinology. 145:569-578 |
| ISSN: | 1479-6805 0022-0795 |
| Popis: | We have previously reported the presence of IGF-I and IGF-binding proteins (IGFBP-2, -3 and -4) in rat milk. Herein, the potential sources of rat milk IGF-I and IGFBPs were investigated. Lactating dams (day 14 postpartum) were separated from their pups and injected intraperitoneally with 0·45 μCi 125I-IGF-I or 125I-IGFBP-3. After 3 h, serum and milk of rats receiving 125I-IGF-I contained 7642 ± 3121 and 14 455 ± 7837 c.p.m./ml respectively. Serum and milk of rats given 125I-IGFBP-3 contained 7232 ± 1366 and 10 371 ± 4091 c.p.m./ml respectively. Sephacryl S-200 gel filtration chromatography demonstrated that the 125I-IGF-I in both serum and milk was primarily in the 150 kDa IGF-binding complex, whereas the distribution of 125I-IGFBP-3 differed between serum and milk. In serum, most of the 125I-IGFBP-3 was in the 150 kDa fraction, while most 125I-IGFBP-3 in milk was in the 40 kDa fraction. Northern analysis of liver showed IGFBP-1 and -3 mRNA expression, with variable expression of IGFBP-2 and -4 mRNA. In contrast, mammary tissue expressed only IGFBP-2 and -4 mRNA, suggesting that these IGFBPs in milk may arise from de novo synthesis within the mammary gland. The lack of detectable IGFBP-3 mRNA in mammary tissue and the translocation of 125I-IGFBP-3 from the serum suggest that milk IGFBP-3 arises from the maternal circulation. Journal of Endocrinology (1995) 145, 569–578 |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|