Acute secretion of immunoreactive parotid hormone in response to different diets in the pig

In pigs, feeding is a physiological stimulus for immunoreactive parotid hormone (iPH) secretion, so the chronic and acute effects of different diets on that secretion were investigated. iPH was measured by radioimmunoassay in pig plasma, in response to feeding three test meals, over 80 days, during which the maintenance diet was switched from standard pig chow to a high-sucrose diet. The maximum iPH response to feeding standard chow was high (177 +/- 32 ng/ml); it was significantly lower with crushed standard chow (58 +/- 9), and even lower with a high-sucrose diet (19 +/- 4), (p < 0.02 between all groups). After changing the maintenance diet from standard chow to high-sucrose diet, the basal iPH titre decreased by 60% and remained significantly lower. During the same time, the iPH response to the three test meals diminished, but not significantly.