Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/1997
Publication Date: N/A
Technical Abstract: The objective of this study was to evaluate the effects of recombinant GH treatment and age on adipose tissue leptin and GH receptor gene expression in the early developmental period of pigs. Three groups of intact males were used in this study. Daily i.m. injections of GH (200 ug/kg) or vehicle were administered beginning at either 1, 4, or 9 wk of age (8 treated and 8 control animals/age group). Animals were sacrificed after 2 wk of treatment. Serum IGF-1 concentrations in GH vs control piglets sacrificed at 3, 6, and 11 wk of age were 83.5 vs 67.8, 200.5 vs 157.9, and 331.3 vs 225.1 ng/ml, respectively (LSE = 25.7; GH, P = .008; Age, P < .0001; GH x Age, P = .16). Serum IGF-1 concentrations and weight gains were highly correlated (r =.9, P < .0001), however growth was unaffected by GH treatment (P = .46). Percent body fat (11.3% overall average), evaluated by dual-energy x-ray absorptiometry (DEXA), did not differ with age (P = .29) and was not affected by GH treatment (P = .17). Levels of G receptor mRNA in adipose tissue were highest at 6 wk of age (P = .051) and were reduced in all age groups by GH treatment (P = .002). GH receptor and leptin mRNA levels were correlated in adipose tissue (r = .69, P = .0007), however the quantity of leptin mRNA was not affected by GH treatment (P = .44). A significant decrease in leptin mRNA values was observed with increasing age (P < .0001), providing the first evidence for developmental regulation of leptin gene expression in the pig.