Secretory profiles and production rate of growth hormone in ruminant lambs

Secretory profiles and production rates of growth hormone (GH) were determined in 6 ruminant lambs during winter. The mean GH concentrations (3.78 +/- 2.17 ng/ml) calculated were based upon blood sampling obtained every 3 min using a withdrawal pump. Body clearance (0.162 +/- 0.031 1/h/kg) was calculated from bolus intravenous oGH administration. The data were analysed by non-linear regression analysis; a bicompartmental model was selected to describe the data. production rate was 14.6 +/- 7.98 micrograms/kg/24 h. It has been emphasized that the experimental design used gave an accurate estimate of GH production rate.