Growth hormone binding protein (GHBP) may be an important
factor in the regulation of growth as well as an indirect,
less invasive way of predicting the status of growth hormone
receptors. Several factors (age, nutritional status, sex,
and glucocorticoid administration) have been reported to
influence circulating growth hormone (GH) levels, growth
hormone receptor (GHR) activity and/or GHBP in mammalian
species. Therefore, the studies conducted in this research
were designed to determine if these factors have any affect
on serum GHBP in the young broiler chicken. Serum GHBP
activity was expressed as a percent specifically bound ¹²⁵IhGH
(%SB), as measured by a dextran-coated charcoal assay.
Serum GHBP activity was highest (mean %SB= 14.6 ± 1.2) at
hatch aniedecreased linearly (r= -.9516) to 4 wk of age
(mean %SB= 4.1 ± 0.6). Sex had no significant affect on
serum GHBP activity from hatch to 4 wk of age. Short term
nutrient deprivation (24 h fast) of 4 wk old birds had no
significant affect on serum GHBP activity, nor did
refeeding. Feeding birds nutrient poor diets (low energy,
low protein or low energy and low protein) did not
significantly affect serum GHBP activity when compared to
birds fed a commercial broiler diet. Pulsatile delivery of
cortisone acetate (1, 5 and 10 mg/d/b) had no affect on
serum GHBP activity at any dose. These results suggest that
serum GHBP activity in the chicken is not affected by many
factors which do influence GHBP in mammalian species. The
lack of response to nutrient deprivation and cortisone
acetate may be a factor related to the age of the birds used
in these studies. / Graduation date: 1993
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36879 |
| Date | 13 August 1992 |
| Creators | Tobar-Dupres, Eric T. |
| Contributors | Davis, Steven L. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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