Neuromuscular studies of turkeys with trienbolone acetate-induced and naturally occurring "leg weakness".

1. In vivo sciatic nerve gastrocnemius muscle preparations were made from 14- to 18-week-old normal turkeys and from those with naturally occurring or trienbolone acetate (TA)-induced "leg weakness". 2. Preparations from leg weakness cases displayed neither accelerated muscle fatigue nor decreased nerve conduction velocities as compared with control preparations. 3. The muscles of the TA-treated turkeys but not of those with naturally occurring leg weakness were hyperexcitable to those of controls. 4. Post-tetanic potentiation of preparations from both naturally occurring and experimentally-induced cases of leg weakness was less than that of control preparations, both before and after partial neuromuscular blockade, significantly so at the lower pulse frequencies used. 5. It is tentatively suggested that the last finding might be of significance in explaining the clinical signs of leg weakness and might be associated with a disordered calcium metabolism.