Seasonal variations in the parathyroid gland of the lizard, Uromastix hardwickii (Gray).

Morphology, histology and seasonal changes in the parathyroid gland of the lizard, Uromastix hardwickii are reported. The lizard possesses a pair of glands consisting of a single type of cells. Parathyroid gland undergoes well defined seasonal changes. During breeding season (Summer) gland showed hyperactivity, whereas in winter, when lizard is quiescent, parathyroid gland shows degenerative changes. Though parathyroid gland from both male and female exhibited hyperactive phase during summer, plasma calcium and phosphorus concentration of female only has increased during this period suggesting that the changes in the parathyroid gland are not due to the endogenous circulating calcium level.