Effects of Pilocarpine Treatment and of Electrical Stimulation of the Vagus Nerve on the Rat Parathyroid Gland, with Special Reference to the Alteration of Storage Granules

Abstract

Effects of pilocarpine treatment and of electrical vagal stimulation on the rat parathyroid were studied ultrastructurally. The number of type I storage granules with a narrow halo (NSG-I) and hat of type II storage granules having a wide halo (NSG-II) were calculated. After pilocarpine treatment, NSG-I gradually decreased and reached a minimum at 30 min; in contrast, NSG-II gradually increased and reached a maximum at 20 min, but thereafter it slightly decreased and instead vacuolar bodies increased. Excluding these alterations, the ultrastructure of parenchymal cells showed no remarkable changes. Electrical vagal stimulation furthermore confirmed these results. Acid phosphatase activity was occasionally found in storage granules of both types in control and experimental rats. It was concluded that storage granules normally may be transformed from type I into type II and finally into vacuolar bodies as a result of hydrolysis, and that these processes may be accelerated by parasympathetic stimulation.

The biological significance of storage granules in rat parathyroid cells

“…Acid phosphatase reaction performed in both control and experimental animals exhibited almost the same results as those observed in the PT gland of rats under short-term high calcium levels (Setoguti et al, 1985a). Therefore, on the basis of our present results, we suggest that SGs are normally transformed from type I into type I1 as a result of hydrolysis, and that hydrolysis of SGs is accelerated by parasympathetic stimulation without changes of SCL (Setoguti et al, 1985b). Fig.…”

Prevention of parturient paresis (milk fever) in dairy cows

“…Some species exhibit diurnal PTH secretory rhythms that may be controlled by these nerves (Fischer ^ al., 1982). Setoguti et^ al. (1985b) have shown that vagal stimulation (parasympathetic) leads to increased conversion of Type I secretory granules to Type II secretory granules.…”