Assessment of factors regulating growth hormone binding in pigs

• Main Author: Mullins, Tracy M.
• Other Authors: Davis, Steven L.
• Language: en_US
• Published: 2013
• Subjects: Insulin-like growth factor-binding proteins; Porcine somatotropin; Swine > Physiology
• Online Access: http://hdl.handle.net/1957/37005

These studies were conducted to examine the influence of several variables on the growth hormone binding protein (GHBP) in serum of pigs. Continuous long term porcine somatotropin (pST) injections (daily for 6-7 wk) increased GHBP activity (p < .05). However, periodic short term pST injections (daily, every second d or every fourth d for 2 wk) did not cause significant change in GHBP levels (p > .40). No difference was observed between fed animals and animals fasted for 5 days (p > .3). Between 0 and 6 mo of age boar and gilt serum GHBP activity were not significantly different from each other, but increased significantly with age in both sexes(p < .0001). There was no significant correlation between serum GHBP and body weight in this study (p > .30). In pregnant sows, GHBP concentrations were highest at the beginning (day 72) of the third trimester (p< .05). These values were compared with information in the literature on serum growth hormone (GH) concentrations and GH receptor activity under similar conditions. Growth hormone receptor activity reported by other researchers and GHBP activity appear to vary concurrently except during fasting which may indicate alternate regulation of either the GHBP or the GH receptor. === Graduation date: 1992