Estimation of Growth Hormone Secretion Rate in Cattle

The amount of growth hormone (GH) degraded (or synthesized) per day was calculated as the product of (a) the concentration of GH-P, (b) the rate of disappearance rate (K) of GH-P and (c) the volume of the space of distribution of GH (GHDS). The average GH-P level was found to be 15 mug. per ml., the K per day was 44.7 and the GHDS was 31.8 1. per animal. The average GH secretion rate (GHSR) was found to be 19.1 mg./day/animal. Two methods were used for the estimation of GHSR and both methods gave comparable results. It is hoped that this technique can be widely used to gain a better understanding of the role of GH in lactation and bovine endocrinology.