INSULIN-LIKE GROWTH FACTOR (IGF)-I, IGF-II, AND IGF BINDING PROTEIN (BP)-2 IN LIVER AND REPRODUCTIVE TISSUES OF PREGNANT PIGS TREATED WITH RECOMBINANTPORCINE SOMATOTROPIN (RPST)

Authors: STERLE, J A - UNIVERSITY OF MISSOURI; PEACOCK, J T - UNIVERSITY OF MISSOURI; BOYD, C K - UNIVERSITY OF MISSOURI; CANTLEY, T C - UNIVERSITY OF MISSOURI; LAMBERSON, W R - UNIVERSITY OF MISSOURI; Matteri, Robert; LUCY, M C - UNIVERSITY OF MISSOURI

Submitted to: American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/19/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Twenty-four pregnant gilts across three replicates were randomly assigned to one of two treatments to determine the effect of rpST on IGF-I, IGF-II and IGFBP-2 mRNA amounts. Gilts received daily im injections of either saline (control) or 5 mg rpST (Monsanto, St. Louis, MO) from d 30 to d 43 of gestation. Replicates 1 and 2 were identical but uteri in replicate 3 were ligated to create fetal crowding. Gilts were slaughtered on d 44 of gestation. Liver, ovary, placental-uterus (uterus with adjacent placental tissue; p-ut), non-placental uterus (n[-ut) were frozen in liquid nitrogen and stored at -80 deg C. Messenger RNA for ST receptor, IGF-I, IGF-II and IGFBP-2 were measured. Gilts treated with rpST had heavier fetuses and placenta (J. Anim. Sci. 1995; 73:2980). The ST receptor mRNA was greatest in liver (P<.05) and was nearly undetectable in ovary or uterus. The liver of rpST-treated gilts had increased IGF-I mRNA (1.18 and .26; SE=.10;rpST and control;P<.01 and decreased IGFBP-2 mRNA (.61 and 1.04; SE=.09; P<.01) The rpST-treatment had no effect (P>.05) on either IGF-I or IGFBP-2 in ovary, p-ut or np-ut. The amount of IGF-I, IGF-II and IGFBP-2 mRNA differed between p-ut and np-ut. Compared to np-ut, the p-ut had more (P<.01) mRNA for IGF-II (1.12 and .57; SE=.04; p-ut and np-ut) and IGFBP-2 (1.78 and .75; SE=.17). The IGF-I mRNA amount, however, was decreased in p-ut compared to np-ut (.29 and .87; SE=.14; P<.05). Uterine ligation and crowding (replicate 3) caused a two-fold increase (P<.05) in IGF-I mRNA in p-ut and np-ut. In summary, increased fetal development after rpST was associated with changes in IGF-I and IGFBP-2 in liver. Uterine IGF-I, IGF- II or IGFBP-2 mRNA amounts were not changed by rpST. Placental location and crowding had the greatest effect on uterine IGF and IGFBP-2 mRNA.