Insulin-Like Growth Factors and Insulin-Like Growth Factor Binding Proteins in Porcine Serum and Milk throughout Lactation

Donovan, Sharon M.; McNeil, Leslie Klis; Jiménez-Flores, Rafael; Odle, Jack

doi:10.1203/00006450-199408000-00005

Cited by 93 publications

(65 citation statements)

References 26 publications

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“…Several earlier studies have shown that human milk contains a variety of hormones and growth factors [15,16,17,18,19,20,21, 24, 26, 27]. In particular, insulin-like growth factors (IGF) and the epidermal growth factor (EGF) were found in physiological concentrations.…”

Section: Discussionmentioning

confidence: 99%

Insulin-Like Growth Factors and Binding Proteins in Early Milk from Mothers of Preterm and Term Infants

et al. 2007

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Breast-fed preterm infants often show a better outcome, partly ascribed to the benefit of insulin-like growth factors (IGFs) and their binding proteins (IGFBP). We compared IGF-I, IGF-II, IGFBP-2 and IGFBP-3 levels, measured by radioimmunoassays in milk samples from 30 mothers of preterm (<31 weeks) and from 19 mothers of term (>37 weeks) infants at days 7 and 21 postpartum. Proteolysis of IGFBP-2 within mother’s milk and digestion of ¹²⁵I-IGF-II and ¹²⁵I-IGFBP-2 by gastric juice from neonates were assessed by electrophoretic techniques. Mean concentrations did not differ between preterm and term milk: IGF-I (2.8 ± 0.2 vs. 2.3 ± 0.1 ng/ml), IGF-II (12.0 ± 0.4 vs. 12.2 ± 0.5 ng/ml), IGFBP-3 (100.0 ± 5.1 vs. 80.0 ± 5.8 ng/ml), but did so for IGFBP-2 (3,144 ± 172 vs. 2,428 ± 188 ng/ml, p < 0.02). Immunoblots revealed 42% (p < 0.05) more IGFBP-2 fragments of 14 and 25 kDa in preterm milk. Incubation with gastric juice caused cleavage of ¹²⁵I-IGFBP-2 and partial cleavage of ¹²⁵I-IGF-II. Mutual complexation protected IGF-II and IGFBP-2 from cleavage, suggesting that both are likely to arrive in the bowel in an intact form to exert promotive effects. The results provide further evidence that IGFBP-2 and IGF-II in breast milk are relevant factors for the early development of preterm infants.

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Section: Discussionmentioning

confidence: 99%

Insulin-Like Growth Factors and Binding Proteins in Early Milk from Mothers of Preterm and Term Infants

et al. 2007

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“…However, the doses of IGF-I administered in these experiments (65-1300 nmol/L) were above the concentrations of IGF-I present in porcine colostrum (13-52 nmol/L) or mature milk (1.3-2.6 nmol/L) (7). It was unknown whether oral administration of lower doses of IGF-I would exert similar biologic effects within the neonatal intestine.…”

mentioning

confidence: 84%

“…IGF-I and IGF-II concentrations were determined by RIA as previously described (7). Samples were analyzed in a single assay with intra-assay coefficients of variation of 4% for IGF-I and 6% for IGF-II in experiment 1 and 6% for IGF-I and 5.2% for IGF-II in experiment 2.…”

Section: Methodsmentioning

confidence: 99%

Investigation of Three Doses of Oral Insulin-like Growth Factor-I on Jejunal Lactase Phlorizin Hydrolase Activity and Gene Expression and Enterocyte Proliferation and Migration in Piglets

et al. 2000

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In a previous study, oral IGF-I at 65 nM increased lactase phlorizin hydrolase (LPH) activity and villus height in piglets, however, the mechanisms were unknown. Herein, the response to a range of doses of IGF-I was investigated and we hypothesized that LPH and villus height would respond to oral IGF-I in a dose-dependent manner. Two 14-d experiments were conducted using cesarean-derived piglets. In experiment 1, piglets (n ϭ 28) were fed formula containing 0, 33, 65, or 131 nmol/L (0, 0.25, 0.5, or 1.0 mg/L) recombinant human IGF-I. In experiment 2, 5Ј-bromodeoxyuridine was administered to piglets fed formula alone (n ϭ 4) or containing 131 nmol/L IGF-I (n ϭ 4). IGF-I did not affect body weight gain or intestinal weight or length. Jejunal villus height and LPH activity were significantly greater in piglets fed 131 nmol IGF-I/L than control piglets. Abbreviations AP-1, activator protein-1 BrdU, 5Ј-bromodeoxyuridine C/EBP, CCAAT/enhancer binding protein EF1-␣, elongation factor 1-␣ FLE, foremost labeled enterocyte HNF-1, hepatocyte nuclear factor-1 LPH, lactase phlorizin hydrolase BB LPH, brush border lactase phlorizin hydrolase proLPH h , high mannose lactase phlorizin hydrolase precursor proLPH c , complex glycosylated lactase phlorizin hydrolase precursor MAPK, mitogen activated protein kinase NHS, normal horse serum PI 3-kinase, phosphatidylinositol 3-kinaseThe presence of IGF-I in colostrum and milk (1) and IGF receptors within the intestine (2) has led to the postulate that milk-borne IGF-I could play a role in neonatal intestinal development (3). Our group and others have shown that orally administered IGF-I stimulates intestinal villus growth (4 -6) and LPH activity (E.C. 3.2.1.23-62) (6) in the neonatal piglet.However, the doses of IGF-I administered in these experiments (65-1300 nmol/L) were above the concentrations of IGF-I present in porcine colostrum (13-52 nmol/L) or mature milk (1.3-2.6 nmol/L) (7). It was unknown whether oral administration of lower doses of IGF-I would exert similar biologic effects within the neonatal intestine. Further, the mechanisms by which oral IGF-I up-regulated intestinal LPH activity and villus growth had not been described. Therefore, the goals of the current study were to determine the impact of a range of doses of oral IGF-I on intestinal villus growth and LPH activity and to investigate potential mechanisms underlying these ef-

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“…Tem-se verificado altas concentrações de IGF-I no colostro de bovinos, com níveis médios de 100 a 500 ng/mL, enquanto, no leite, são inferiores a 40 ng/mL no leite (Zhao et al, 1991;Vacher & Blum, 1993;Donovan et al, 1994;Hardon et al, 1997;. Nesta pesquisa, o objetivo da administração de rbST aos animais durante seu período seco foi de aumentar a concentração sérica de IGF-I e, conseqüentemente, as concentrações no colostro e subseqüentes secreções lácteas (Figura 3).…”

Section: Period Meanunclassified

“…Fleenor & Stott (1980) classificam colostros com teores abaixo de 21,8 mg de imunoglobulinas/mL como de baixo valor imunológico e, acima de 49,82 mg/mL, como de alto valor imunológico. Os valores observados neste estudo encontram-se entre os mais elevados para vacas da raça Holandesa, que variam entre 50 e 90 mg/mL (Burton et al, 1989;Tyler et al, 1999;Morin et al, 2001).…”

Section: Period Meanunclassified

IGF-I e IgG séricos e nas secreções lácteas em vacas tratadas com rbST no período pré-parto

et al. 2005

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RESUMO -Foram utilizadas 42 vacas holandesas gestantes e multíparas, distribuídas ao acaso em dois grupos, com o objetivo de se determinar possíveis alterações na concentração de IGF-I no colostro e nas secreções lácteas em resposta a mudanças na concentração sérica de IGF-I pré-parto, além de se avaliar comparativamente a flutuação sérica pré-parto de IGF-I em relação a IgG. O grupo tratado (n=21) recebeu 500 mg de somatotropina bovina recombinante (rbST) e o grupo controle (n=21) injeções de vitamina E. Os tratamentos foram iniciados 35 dias pré-parto e repetidos a cada 14 dias até o parto. Semanalmente, até o parto, avaliou-se o escore corporal (EC) e coletaram-se amostras de sangue da veia mamária. Foram amostrados o colostro e as secreções lácteas diariamente por sete dias pós-parto. O EC e a concentração sérica de ácidos graxos não-esterificados não diferiram entre os grupos. O grupo rbST apresentou maiores concentrações séricas de IGF-I na segunda e quarta semanas após o início dos tratamentos, não sendo encontradas diferenças entre os tratamentos ao parto. A concentração de IGF-I foi superior no colostro das vacas tratadas com rbST, não diferindo nas secreções subseqüentes. As concentrações séricas de IgG não diferiram entre tratamentos durante todo o período experimental, assim como as do colostro e demais secreções lácteas. As concentrações séricas de IGF-I e IgG variaram em função do período experimental, diferindo na amplitude e refletindo as grandes mudanças que ocorrem no último mês de gestação.Palavras-chave: colostro, fator de crescimento semelhante à insulina-I, imunoglobulinas, somatotropina IGF-I and IgG Serum Concentrations and in Mammary Secretions in Cows Treated with rbST PrepartumABSTRACT -Forty-two Holstein cows, pregnants and multiparous, wereassigned randomly to two groups to determine the possible alterations of IGF-I concentration in colostro and mammary secretions by changes in pre-partum blood serum IGF-I concentration, and also to compare its temporal changes with the serum immunoglobulin G (IgG) in pre-partum period. The treated group (n=21) received 500 mg of recombinant bovine somatotropin (rbST), and the control group (n=21) vitamin E injections. The treatments had been initiated 35 days prepartum and repeated each 14 days until partum. Weekly it was evaluated body condition scores and was collected blood by mammary venepuncture until partum. Colostrum and mammary secretions were collected daily for seven days pos-partum. Body condition scores and nonesterified fatty acid concentration did not differ between the groups. To the rbST group IGF-I concentration was superior on second and fourth weeks after the treatment had been initiated. However, no treatment differences were found at partum. Concentration of IGF-I was superior in colostrum of cows treated with rbST, but it did not differ in subsequent mammary secretions. IgG serum concentration did not differ between treatments during the experimental period, neither in colostrum and subsequent mammary secretions. IGF-I and IgG...

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Insulin-Like Growth Factors and Insulin-Like Growth Factor Binding Proteins in Porcine Serum and Milk throughout Lactation

Cited by 93 publications

References 26 publications

Insulin-Like Growth Factors and Binding Proteins in Early Milk from Mothers of Preterm and Term Infants

Insulin-Like Growth Factors and Binding Proteins in Early Milk from Mothers of Preterm and Term Infants

Investigation of Three Doses of Oral Insulin-like Growth Factor-I on Jejunal Lactase Phlorizin Hydrolase Activity and Gene Expression and Enterocyte Proliferation and Migration in Piglets

IGF-I e IgG séricos e nas secreções lácteas em vacas tratadas com rbST no período pré-parto

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