Parathyroid Hormone and Triglyceride Transport: Effects on Triglyceride Secretion Rates and Adipose Tissue Lipoprotein Lipase in the Rat

In order to determine the effects of parathyroid hormone on triglyceride transport, male Sprague-Dawley rats were injected with parathyroid extract for eight days and triglyceride secretion rates (TGSR) and adipose tissue lipoprotein lipase (LPL) activity were determined. Parathyroid hormone-treated rats demonstrated significantly lower (p less than .005) TGSR in the basal overnight fasted state 15 hours after the previous injection, but this effect on TGSR was not apparent 3 hours after PTE injection when the rats were allowed to eat. In contrast, LPL activity was significantly reduced in the PTH-treated animals at 3 hours and no effect was apparent on this index of triglyceride removal at 15 hours. These findings suggest that parathyroid hormone may exert independent influences on triglyceride production and removal and thus may alter triglyceride homeostasis in conditions in which parathyroid hormone levels are abnormally increased.