EFFECTS OF PROGESTERONE ON THE ULTRASTRUCTURE OF THE GOLDEN-HAMSTER PARATHYROID-GLAND

The ultrastructure of the parathyroid glands in golden hamsters after administration of progesterone was investigated. In the parathyroid gl ands of the female hamsters after administration of progesterone, the mean serum calcium concentration was significantly higher when compare d to that of the control hamsters. In the male experimental hamsters, the percentage area occupied by Golgi complexes and lipid droplets was significantly increased when compared to that of the control hamsters , respectively. In the female hamsters after administration of progest erone, the percentage area occupied by large vacuolar bodies was signi ficantly decreased when compared to that of the control hamsters. In t he male and female experimental hamsters, the mean number of secretory granules per 100 mu m(2) of cytoplasm showed a significant increase c ompared with that of the male and female control hamsters, respectivel y. These findings suggest that the secretory activity of the parathyro id glands may be stimulated in response to hypocalcemia induced by pro gesterone.