Role of protein kinase C in cholinergic stimulation of lacrimal gland protein secretion

Abstract

The purpose of this study was to determine the role of protein kinase C (PKC) isozymes in carbachol-induced protein secretion in the lacrimal gland. Three isoforms of PKC are present in rat lacrimal gland: PKC-α, -δ and -g3. Carbachol translocated PKC-ε during 5 s incubation. Pretreatment with PdBu for 0 to 4 h down-regulated PKC-α by 31% at 20 min, PKC-ε by 36% at 2 h, and PKC-δ by 37% at 4 h. A 2 h phorbol ester treatment inhibited carbachol-induced secretion completely at 1 min and partially at 5, and 20 min, but did not alter the carbachol-induced increase in the intracellular [Ca 2+]. We conclude that PKC-α and -g3, but not PKC-δ, are implicated in cholinergic agonist-induced protein secretion in rat lacrimal gland.