Salivary Secretion of a Substance Immunologically Identical to the α-Subunit of 7S Nerve Growth Factor 1

Summary

Mouse saliva elicited by several secretagogues is shown by immunodiffusion and complement fixation to contain a factor immunologically identical to the α-subunit of 7S nerve growth factor. The relative specific activities of α-subunitlike material are 790, 810, 33, and 29 complement fixation units per μg of protein in secretions elicited by epinephrine, norepinephrine, isoproterenol, and pilocarpine, respectively. Thus, samples of saliva elicited by agonists which activate α-adrenergic receptors have a 25-fold greater relative specific activity than those elicited by agonists which activate either β-adrenergic or muscarinic receptors. In light of earlier experiments on the effects of specific receptor blockers on drug-induced salivation, these results strongly suggest that α-subunitlike material is preferentially released by activation of α-adrenergic receptors. In addition, data are presented which suggest that the α-, β-, and γ-subunits of 7S nerve growth factor do not have common antigenic determinants. Finally, Burroughs-Wellcome antiserum prepared against the β-subunit of nerve growth factor is shown to contain antibodies against all three subunits and one or more of the mouse gamma globulins.