Impaired adrenergic stimulation of rat parotid cell glucose oxidation during aging: the role of calcium.

Adrenergic stimulation of glucose oxidation by epinephrine is reduced by 30 to 40% in isolated rat parotid cell aggregates from aged rats compared with young adults. Such impairment affects both the external calcium dependent and independent components of the response. Age-related differences in glucose oxidation are obliterated if adrenergic receptors are bypassed and stimulation achieved by exposing cells to various concentrations of calcium in the presence of the ionophore, A23187. Thus, impaired calcium mobilization may play, in part, a role in reduced rat parotid adrenergic metabolic responsiveness during aging.