PLASMA CONCENTRATIONS OF GROWTH HORMONE DURING GROWTH IN NORMAL AND TESTOSTERONE-TREATED CHICKENS

Abstract

Department of Zoology, University of Hull, Hull, HU6 7RX and * Department of Physiology, Rutgers University, New Brunswick, New Jersey 08903, U.S.A. (Received 9 May 1978) Recent avian studies (Harvey, Godden & Scanes, 1977; Harvey, Scanes, Falconer, Bolton & Chadwick, 1977) have established a definite pattern of growth hormone (GH) secretion during growth, with high plasma concentrations in young growing birds and low levels in adults. These observations indicate that the concentration of immunoreactive GH in the circulation may be related to the rate of body growth. The aim of the present study was, therefore, to determine whether experimental modification of growth was accompanied by corresponding alterations in GH secretion. Since testosterone suppresses growth in cockerels (Visco, 1973), plasma concentrations of GH were determined during growth in control and testosterone-implanted birds. Seven 2-week-old cockerels (Thornber 909 strain) were implanted subcutaneously with a testosterone pellet (Intervet, 100 mg) in the nape