We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Impact of exogenous ghrelin administration on circulating concentrations of luteinizing hormone in steers.
- Authors
Daniel, J. A.; Perry, G. A.; Wertz-Lutz, A. E.
- Abstract
Four steers (450 ± 13.1 kg) were used in a crossover design to determine the effects of intravenous infusion of bovine ghrelin (bGHR) on plasma concentrations of luteinizing hormone (LH). Steers were fed individually once daily (0800 h) and allowed to consume ad libitum until 2000 when feed was removed. Daily feed allotment was sufficient to result in ≥10% feed refusal. On the day of the experiment, serial blood samples were collected from steers fitted with an indwelling jugular catheter at 15-min intervals from 0600 through 1800 h. Plasma was assayed for LH by RIA. Saline (SAL) or bGHR was infused via jugular catheter at 1200 and 1400 h, which were times when steers usually did not eat feed. Exogenous bGHR was infused to achieve a plasma concentration of 1000 pg/mL. Previous research has indicated a peak bGHR concentration of 1000 pg/mL for fasting steers. Steers were allowed 5 d to adjust between treatment periods. Then, treatments were switched between steer groups, and the sampling period was repeated. Mean concentrations and area under the concentration curve were determined for LH following administration bGHR or SAL treatment at 1200 and 1400 h. Effect of treatment, period, steer and the treatment*period interaction on mean concentrations and area under the concentration curve for LH was determined by ANOVA. Mean plasma concentrations of LH and area under the concentration curve did not differ between bGHR or SAL treated steers following the 1200 h infusion (2.4 ± 0.1 vs. 3.0 ± 0.4 ng/ml and 247.5 ± 13.7 vs. 309.9 ± 36.2 ng/ml, respectively; P > 0.29) or the 1400 h infusion (2.4 ± 0.2 vs. 2.9 ± 0.2 ng/ml and 516.0 ± 58.6 vs. 651.2 ± 42.8 ng/ml, respectively; P > 0.27). Plasma concentrations of growth hormone (GH) and bGHR were also determined and previously reported that exogenous administration of bGHR increased plasma concentrations of GH in these steers. These date indicate bolus administration of bGHR sufficient to alter plasma concentrations of GH does not alter plasma concentrations of LH in steers.
- Subjects
LUTEINIZING hormone; GASTROINTESTINAL hormones; SOMATOTROPIN; BEEF cattle; IMPLANTABLE catheters; TREATMENT effectiveness; INTRAVENOUS therapy
- Publication
Journal of Animal Science, 2006, Vol 84, p205
- ISSN
0021-8812
- Publication type
Article