The Mechanism of Enzyme Secretion by the Cell

Abstract

Preparation of rat parotid slices in cold medium caused extensive leakage of amylase during subsequent incubation. Enzyme secretion, by slices not prepared in the cold, was almost absolutely dependent on the addition of an inducer such as epinephrine. Both epinephrine and norepinephrine were more effective than other agents tested. Since epinephrine was apparently consumed during incubation, a sufficient excess of the hormone was required to achieve a maximal yield of enzyme secreted into the medium. Further experiments indicated that 3′5′ cyclic AMP is an intermediate in the induction of enzyme secretion by epinephrine. The dibutyryl and monobutyryl derivatives of cyclic AMP caused amylase secretion at a rate which was even slightly higher than that obtained with epinephrine. An initial lag period was apparently due to the slow penetration of such compounds into the cell.