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FACTORS AFFECTING THE SECRETION OF PHOSPHATE IN PAROTID SALIVA IN THE SHEEP AND GOAT
Author(s) -
MañasAlmendros M.,
Ross R.,
Care A. D.
Publication year - 1982
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0144-8757
DOI - 10.1113/expphysiol.1982.sp002635
Subject(s) - saliva , secretion , phosphate , parotid gland , biology , endocrinology , medicine , dentistry , biochemistry
The relationship between the concentration of phosphate in plasma and parotid saliva was studied in six conscious sheep and a g+oat, either intact or thyroparathyroidectomized ( t.x.p.t.x.), under conditions designed to minimize marked fluctuations in flow rate of saliva. A linear relationship between acutely induced changes in plasma phosphate concentration and the phosphate level in saliva has been demonstrated in both intact and t.x.p.t.x. animals. Dietary phosphorus depletion caused adaptation of salivary phosphate concentration so that less was secreted at a given concentration of plasma phosphate. Attention is drawn to the similarity between this phenomenon and that already described for the proximal renal tubule. Parathyroid hormone (PTH) was shown to reduce the salivary phosphate concentration with little or no effect on phosphataemia. The administration of 1,25‐dihydroxycholecalciferol (1,25(OH) 2 CC) also caused a reduction in salivary phosphate concentration despite hyperphosphataemia and hypercalcaemia. It is suggested that salivary phosphate concentration can be influenced directly by the concurrent level of plasma phosphate but that this relationship can be modified directly by the circulating concentration of 1,25(OH) 2 CC and indirectly by PTH via increased production of 1,25(OH) 2 CC.