Abstract
The ultrastructure of the parathyroid glands of magnesium-treated golden hamsters exposed to a 5 gravity environment was studied. In the parathyroid glands of the magnesium-treated animals exposed to a hypergravity environment, the Golgi complexes and cisternae of the granular endoplasmic reticulum were increased as compared to those of the magnesium-treated animals and decreased as compared to those of animals exposed to a hypergravity environment, but were almost the same as those of the control animals. In the control and experimental animals, the chief cells were rich in free ribosomes and mitochondria. In addition, numerous secrectory granules were situated close to the plasma membrane in the magnesium-treated animals exposed to a hypergravity environment. These observations suggest that the synthesis of parathroid hormone may be stimulated in the parathyroid glands of magnesium-treated hamsters exposed to hypergravity environment.
