Regulation of insulin-like growth factor binding proteins in young growing animals by alteration of energy status.
The regulation of plasma insulin-like growth factor binding proteins (IGFBPs) by energy status has been assessed in 2-month-old pigs. Energy balance was modified by altering thermoregulatory demand and energy intake, with litter-mates being kept for several weeks at either 35 or 10 degrees C on a high (H) or low (L) level of food intake (where H = 2L); plasma samples were taken 20-24 h after the last meal. The two major forms of circulating IGFBP, as estimated by Western blot analysis, were identified putatively as IGFBP-2 and IGFBP-3 (relative molecular weights of 34 and 40-45 kDa respectively). There were significant differences in IGFBP profiles between the four treatment groups of 35H, 35L, 10H and 10L: the 40-45 kDa IGFBP (putative IGFBP-3) was elevated both in the warm and on a high food intake (P < 0.001), and there was a marked reciprocal relation between the 40-45 and 34 kDa IGFBPs. The relative concentration of the 34 kDa IGFBP (putative IGFBP-2) was greatest in the 10L and least in the 35H group. It is concluded that long-term alterations in energy balance, induced by changes in either intake or thermoregulatory demand, can significantly affect the plasma profile of IGFBPs during the first two months of life.
Dauncey
M J
MJ
Department of Molecular and Cellular Physiology, AFRC Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, England.
Rudd
B T
BT
White
D A
DA
Shakespear
R A
RA
D000375:Aging / Q000097:blood* / Q000502:physiology; D000818:Animals; D001345:Autoradiography; D015153:Blotting, Western; D001833:Body Temperature Regulation / Q000502:physiology; D002352:Carrier Proteins / Q000097:blood* / Q000502:physiology; D003720:Densitometry; D004435:Eating / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D004734:Energy Metabolism / Q000502:physiology*; D006128:Growth / Q000502:physiology; D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018974:Insulin-Like Growth Factor Binding Protein 4; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000502:physiology; D008970:Molecular Weight; D013552:Swine / Q000097:blood / Q000254:growth & development* / Q000502:physiology
D002352:Carrier Proteins; D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018974:Insulin-Like Growth Factor Binding Protein 4; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I