Journal of Andrology, Vol 5, Issue 5 351-360, Copyright © 1984 by The American Society of Andrology

JOURNAL ARTICLE

Protein secretion by the rat epididymis can be selectively modified in vitro by local anesthetics, glucose deprivation, dinitrophenol, ouabain, and ionophores

D. E. Brooks

Protein secretion by the caput epididymidis has been examined in vitro using radioactive methionine as a precursor for protein synthesis. Newly synthesized and secreted proteins were separated by gel electrophoresis and visualized by fluorography. Local anesthetics such as procaine had the ability to reduce the secretion of some, but not all, proteins. Selective inhibition of secretion of the same proteins occurred when either dihydrocytochalasin B, monensin, ouabain, or dinitrophenol was added to the medium, or when the concentration of glucose was reduced below 1 mM. Calcium ionophore also selectively modified protein secretion, but the proteins affected were different from those influenced by local anesthetics. Other agents tested (eg, adrenergic and cholinergic agonists and antagonists, sodium pentobarbitone, antipsychotic drugs, cyclic AMP, colchicine) did not selectively modify protein secretion, even though overall protein synthesis and secretion was reduced in some instances. Procaine and dihydrocytochalasin B also reduced glucose utilization by epididymal tissue and it is suggested that these agents may reduce protein secretion by limiting the supply of energy for the exocytotic process. This conclusion is supported by the fact that dinitrophenol, an uncoupler of oxidative phosphorylation, caused a similar alteration in protein secretion. The possibility that a restricted energy supply modifies protein secretion primarily by creating a disturbed intracellular Na/K balance is suggested by the observation that the monovalent ionophore, monensin, and the Na/K ATPase inhibitor, ouabain, were both able to duplicate the effects of the local anesthetics.