[Human somatotropin stimulates the growth of young American lobsters, Homarus americanus (Crustacea, Decapoda)]

Larval and postlarval lobsters, injected with human somatotropin (STH, or growth hormone), grew at a more rapid rate than untreated control animals over succeeding molts. Their mean carapace length was significantly longer than that of controls and they were heavier, although the moisture content of treated and control animals was similar. Injected STH increased the growth rate of individual animals by 10 to 20%. This is the first evidence for a growth enhancing effect of human somatotropin on a Crustacean.