Triiodothyronine in rat submaxillary salivary gland: effects of altered adrenergic function

To determine whether changes in adrenergic nerve terminal activity may influence tissue metabolism of iodothyronines, sympathetic nervous function of the rat submaxillary salivary gland was altered, and effects on salivary gland triiodothyronine (T3) uptake and retention measured. Following unilateral superior cervical ganglionectomy, denervated salivary gland contained 24% less (p less than 0.02) radioimmunoassayable T3/mg and took up 20% less (p less than 0.001) intravenously administered 125I-T3/mg than the contralateral innervated gland. Effects were similar at 7, 14 and 56 days following ganglionectomy and could not be accounted for by post-denervation changes in the delivery of the isotope, in total salivary gland water, in vascular volume or in extracellular or intracellular fluid spaces. When reserpine was administered to unilaterally ganglionectomized animals, uptake of 125I-T3/mg in the innvervated gland was reduced by 10% (p less than 0.005), relative to the denervated gland. The results suggest that loss or diminution of peripheral adrenergic nerve terminal activity reduces tissue uptake and retention of T3.