@article{johnson_coffey_esbenshade_schricker_1990, title={EFFECT OF GROWTH HORMONE-RELEASING FACTOR (1-44)NH2 ADMINISTRATION ON SOMATOTROPIN IN PIGS}, volume={70}, ISSN={["0008-3984"]}, DOI={10.4141/cjas90-098}, abstractNote={ Two experiments were conducted to examine the dose response and optimum pattern of subcutaneous (s.c.) administration of human growth hormone-releasing factor [hGRF (1–44)NH2]on serum somatotropin (ST) in barrows. In exp. 1, 10 barrows (79.9 ± 3.3 kg) were used in a replicated 5 × 5 Latin square and blood samples were collected for 300 min from a single injection of hGRF. Injecting 0, 1, 10, 40 or 100 μg hGRF kg−1 resulted in dose related increase (P < 0.01) in peak concentrations of pST (3.93, 4.41, 10.61, 16.01 and 23.56 ng mL−1), and area under the ST response curve (AUC) (565.4, 546.2, 757.5, 1048.0 and 1314.0 ng min mL−1, respectively). The 40 μg kg−1 dose resulted in a higher (P < 0.05) peak pST and AUC than 0 or 1 μg hGRF kg−1. Peak concentration and AUC were greater (P < 0.05) for the 100 μg hGRF kg−1 dose compared with the 0, 1 and 10 μg hGRF kg−1 doses, but there was no difference between the 40 and 100 μg kg−1 doses. In exp. 2, eight barrows (85.4 ± 8.0 kg) were used in a replicated 4 × 4 Latin square to examine the relationship between pattern of hGRF administration and serum ST. Blood samples were collected −15, 0 and 15 min from initiation of administration and then hourly for 24 h. Treatments were designed to deliver 160 μg hGRF kg−1 every 24 h and were administered as 40 μg kg−1 injected four times daily, 80 μg kg−1 injected twice daily or by continuous s.c. infusion. There was no difference (P > 0.10) between treatments for peak ST concentration, AUC or area above the ST baseline. These data indicated a dose response to s.c. hGRF injections and ST in barrows. Further, ST response was not altered by the pattern of s.c. administration when barrows received 160 μg hGRF kg−1 daily by either 4 or 2 discrete injections or by continuous infusion. Key words: Swine, somatotropin, growth hormone-releasing factor }, number={3}, journal={CANADIAN JOURNAL OF ANIMAL SCIENCE}, author={JOHNSON, JL and COFFEY, MT and ESBENSHADE, KL and SCHRICKER, BR}, year={1990}, month={Sep}, pages={785–793} }
 @article{johnson_coffey_esbenshade_schricker_pilkington_1990, title={The effect of human growth hormone-releasing factor or porcine somatotropin on serum hormones and metabolites, growth performance and carcass traits in swine}, volume={68}, DOI={10.2527/1990.68103204x}, abstractNote={Forty barrows (77.9 +/- 5.5 kg BW) were allotted to one of five treatment groups to examine the effects of various doses of human growth hormone-releasing factor (1-44)NH2 (hGRF) or porcine somatotropin (pST) administered twice daily on serum hormones and metabolites, performance and carcass traits. Barrows were injected s.c. with either a placebo, 10 micrograms hGRF.kg BW-1.12 h-1, 20 micrograms hGRF.kg BW-1.12 h-1, 20 micrograms pST.kg BW-1.12 h-1 or 40 micrograms pST.kg BW-1.12 h-1 for a 36-d growth trial. Blood samples were collected from 13 barrows at intervals for 360 min after injection on d 21. Compared with the placebo, 10 micrograms hGRF.kg-1.12 h-1 increased (P less than .01) serum pST and insulin and decreased (P less than .001) urea N. Injecting 20 micrograms hGRF/kg.12 h-1 elevated (P less than .001) serum pST, insulin and insulin-like growth factor-I (IGF-I) but lowered (P less than .001) urea N. Exogenous pST increased (P less than .001) serum pST, insulin, IGF-I and glucose but decreased (P less than .001) urea N. Growth rate tended to increase, and feed intake and feed/gain decreased, in a dose-related manner in response to hGRF. Also, pigs receiving 10 or 20 micrograms hGRF.kg-1.12 h-1 had reduced (P less than .1) backfat and increased (P less than .1) loineye area and percentage lean in the ham compared with pigs receiving the placebo. At equal doses, pST elicited more dramatic improvements in performance and carcass criteria than did hGRF.(ABSTRACT TRUNCATED AT 250 WORDS)}, number={10}, journal={Journal of Animal Science}, author={Johnson, J. L. and Coffey, M. T. and Esbenshade, K. L. and Schricker, B. R. and Pilkington, D. H.}, year={1990}, pages={3204} }