No abstract

The effects of water deprivation on the adrenal glands were studied in two avian species, the pigeon and the house sparrow. Dehydration failed to produce any change in the histology of the adrenal gland of the house sparrow, while, in the pigeon, medullary lobes were constricted and myeloid tissues increased. Biochemical observations showed that dehydration resulted in the decrease of both norepinephrine (34%) and epinephrine (50%) from the adrenal medulla of the house sparrow, whereas, in the pigeon, only epinephrine (45%) decreased following water deprivation. Water deprivation caused an increase of glandular corticosterone both in the pigeon (375.7%) and in the house sparrow (336.7%). The present observations illustrate that participation of corticosterone in dehydration is possibly universal in birds. By contrast, the differential responsiveness of the catechol hormones in these two species was noted. However, the adrenomedullary catecholamine response during water deprivation was independent of the NE: E ratio of both species. To explain this, the reno-physiological status and concentration of other hormones in these birds needs to be considered.