GH and IGF-I binding in adipose tissue, liver, and skeletal muscle in response to milk intake level in piglets.
Two experiments were undertaken to get a better understanding of the regulation of the GH/IGF-I axis by nutritional status in suckling piglets. In experiment 1, 18 newborn unsuckled piglets were bottle-fed low (L), intermediate (I), or high (H) levels of sow colostrum and milk from birth to 7 days of age. L and H levels corresponded to maintenance requirement and ad libitum intake, respectively. Plasma IGF-I and 43-39 kDa IGFBP levels decreased (P<0.05) with the reduction of milk intake. Specific binding of (125)I-bGH in liver decreased (P<0.01) with decreasing milk intake. It did not differ (P>0.1) between the groups in skeletal muscle. Specific binding of (125)I-IGF-I increased (P<0.05) with decreasing milk intake in skeletal muscle but did not differ (P>0.1) between the three groups in liver. In experiment 2, variation in milk intake was induced by litter size manipulation. In the 24 h following birth, the litter sizes of six litters were normalized to 6 (L6) or 12 piglets (L12). Animals were killed at 21 days of age. Plasma IGF-I concentrations (P<0.001) and 43-39 kDa IGFBP levels (P<0.05) were lower in L12 than in L6. Specific binding of (125)I-bGH in adipose tissue, liver, and skeletal muscle did not differ (P>0.1) between the two groups. Specific binding of (125)I-IGF-I in liver was lower (P<0.001) in L12 than in L6, whereas it did not differ (P>0.05) between groups in other tissues. In conclusion, the present report shows that undernutrition consistently decreases plasma IGF-I and 43-39 kDa IGFBP levels but produces variable responses at the GH and IGF-I binding levels in piglets.
Louveau
Isabelle
I
Unité Mixte de Recherches sur le Veau et le Porc, Institut National de la Recherche Agronomique, 35590 Saint Gilles, France. louveau@st-gilles.rennes.inra.fr
Le Dividich
Jean
J
D000273:Adipose Tissue / Q000737:chemistry / Q000378:metabolism; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D015153:Blotting, Western; D013006:Growth Hormone / Q000378:metabolism*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000032:analysis; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D008892:Milk; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism; D013552:Swine / Q000378:metabolism*; D015430:Weight Gain
D018969:Insulin-Like Growth Factor Binding Proteins; D007457:Iodine Radioisotopes; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone