Plasma growth hormone concentrations during growth in turkeys

The concentrations of circulating GH were low in 1-week-old birds (male plasma pool 30 ng/ml, female 32 ng/ml), reached a maximum at 7 weeks in male birds (142 +/- 26 SEM ng/ml) or 4 weeks in females (185 +/- 32 ng/ml) and then decreased to 17-3 +/- 2-8 ng/ml in males and 8-7 +/- 0-6 ng/ml in females at 17 weeks. 2. Significant inverse correlations between GH concentration and age or body weight were found (male, r = -0-693), female, r = -0-623). 3. In males, but not females, the weekly increase in body weight was correlated with the plasma GH concentration (r = 0-291).