Effect of beta-agonists on expression of calpain and calpastatin activity in skeletal muscle.

Administration of beta-adrenergic agonists to domestic species can lead to skeletal muscle hypertrophy, probably by reducing the rate of myofibrillar protein breakdown. Myofibrillar breakdown is associated with the calcium-dependent proteinase system (calpains I,II and calpastatin) whose activity also changes during beta-agonist treatment. A number of growth trials using the agonists cimaterol and clenbuterol with cattle, sheep, chicken and rat are reported which suggest a general mechanism whereby beta-agonists reduce calpain I activity, but increase calpain II and calpastatin activity in skeletal muscle.

Polygalacturonase expression during leaf abscission of normal and transgenic tomato plants.

Polygalacturonase (PG, EC 3.2.1.

The relation between dietary restriction or clenbuterol (a selective beta 2 agonist) treatment on muscle growth and calpain proteinase (EC 3.4.22.17) and calpastatin activities in lambs.

1. Lamb growth trials were designed to modify growth and protein content of muscle by diet and also by beta-agonist treatment, and to correlate any changes to the activities of calpain proteinases (EC 3.4.