Modification of in vivo lacrimal gland secretion by 2,4-dinitrophenol.

Mecholyl-stimulated flow from the excretory duct of the rabbit lacrimal gland in vivo was recorded continuously and samples of Mecholyl-stimulated fluid were collected before, during, and after 30 min of local intra-arterial infusion of 2,4-dinitrophenol (DNP). Compared with the control period, Mecholyl-stimulated flow during the DNP infusion was 60-70% less; [K+] was the same and [Na+] and [Cl-] were higher in the Mecholyl-stimulated fluid. The changes that occurred during the DNP infusion were not produced by infusion of the solvent (NaHCO3) or an acid with similar pK (para-aminohippuric acid) nor were the changes related to any effect of DNP on the general circulation. The magnitude of the changes during the DNP infusion increased as the dose of DNP increased and the inhibition of flow changes in [Na+] and [Cl-] during the DNP infusion were reversible. The results are compatible with the hypothesis that stimulation by Mecholyl involves oxidative metabolsim at the duct level but they do not exclude the possibility that oxidative metabolism may also be involved in formation of the primary fluid at the acinar level.