Effect of photoperiod on the adrenal activities of male rose ringed parakeet, Psittacala krameri.

Adult male rose ringed parakeets were exposed to very long photoperiod (22 hr L: 2 hr D) and very short photoperiod (2 hr L: 22 hr D) daily for 60 days during different phases of the annual testicular cycle. Adrenal activities of the experimental birds were compared with that of parallel held natural photoperiodic birds. Marked atrophy of adrenocortical cells was noted in the glands of long photoperiod (22 hr L:2 hr D) during different phases, i.e., post-breeding, quiescent and pre-breeding phases of annual gonadal cycle. The atrophied cells were not uniformly distributed in different groups of long photoperiod responsive birds. During pre-breeding, post-breeding and quiescent phases marked atrophy of the adrenocortical cells were restricted to the sub capsular zone of the gland. The cytometric and karyometric studies also revealed significant decrease in the cortical cord width and diameter of nuclei in the cortical cells in either subcapsular zone in the gland of long photoperiodic birds considered for treatment during pre-breeding, post-breeding and quiescent phase or in both the sub capsular zone and the inner zone. The cytometric and karyometric values did not show any change from control birds.

Effect of hypoxia on the circulating levels of essential mineral elements in rats.

Changes occurring in concentrations of certain trace metals and electrolytes viz. chromium, copper, zinc, sodium, potassium, calcium, magenesium and chloride in plasma of rats exposed to intermittent hypobaric hypoxia were evaluated. Batches of Sprague-Dowley rats (12 in each group) were exposed for 1, 7,14 and 21 days to a simulated altitude 7,620 m for 6 h per day and one group of unexposed animals was kept as control. There was a significant rise of 153% in plasma chromium levels of 1 day exposed group in comparison to the unexposed group which tends to normalise on subsequent exposure. There was a gradual increase in plasma copper levels of 9.0, 28.2, 62.6 and 65.6% respectively in 1,7,14 and 21 days exposed rats in comparison to unexposed rats. On the other hand plasma zinc levels were seen to be decreasing during entire exposure. Plasma sodium levels decreased initially in 1 and 7 day exposed rats and increased in later groups whereas plasma potassium levels of exposed groups remained low in comparison to unexposed group. Chloride levels were found to be elevated in 14 and 21 day exposed groups.The plasma calcium and magnesium levels were higher in all exposed groups over unexposed groups. Changes in chromium, copper and zinc observed in the present study during exposure to hypoxic stress may be responsible for the hyperglycemia and anorexia encountered during intial phase of high altitude acclimatisation.