Growth hormone increases insulin-like growth factor-I (IGF-I) and decreases IGF-II in plasma of growing pigs.
Insulin-like growth factor-I (IGF-I) and IGF-II have been measured in plasma obtained from male and female pigs of two strains during daily administration of pituitary-derived porcine GH (pGH; 100 micrograms/kg) from 60 to 90 kg body weight. Each plasma sample was first chromatographed to separate the IGF from binding proteins in order to obtain reliable measurements. IGF-I concentrations showed no differences between strains, but were higher in untreated males (497 +/- 43 (S.E.M.) micrograms/l) than females (299 +/- 15 micrograms/l). GH-treated animals had two-fold higher concentrations of IGF-I. IGF-II concentrations were not significantly different between sexes or strains, but were decreased in pigs treated with pGH (299 +/- 28 micrograms/1) compared with controls (431 +/- 32 micrograms/l). Binding protein concentrations, measured as interference in the IGF-I and IGF-II assays, were not different between sexes or strains, but were increased in pGH-treated animals. Taken together, these results indicate that in addition to the expected increase in IGF-I concentrations, exogenous administration of pGH to pigs leads to an increase in IGF-binding protein and a depression in IGF-II concentrations.
Owens
P C
PC
CSIRO Division of Human Nutrition, Adelaide, South Australia.
Johnson
R J
RJ
Campbell
R G
RG
Ballard
F J
FJ
D000818:Animals; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007335:Insulin-Like Growth Factor II / Q000032:analysis*; D008297:Male; D011956:Receptors, Cell Surface / Q000097:blood; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000032:analysis*; D013552:Swine / Q000097:blood / Q000254:growth & development*
D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone