ISSN:
1432-2013
Keywords:
Arginine vasotocin
;
Avian volume sensitivity
;
Avian kidney
;
Salt gland
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Blood volume changes consisting in the removal and reinfusion respectively, of 10% of the estimated blood volume (23.2 ml on average) were induced to determine their effects on the blood concentration of arginine vasotocin (AVT), the antidiuretic hormone (ADH) of birds, in fresh water adapted ducks (water ducks) with blood osmolalities and ADH concentrations similar to those of normally hydrated mammals, and in salt water adapted ducks (salt ducks) with chronically elevated blood osmolalities and ADH concentrations. The investigations were carried out in steady state conditions, when infusion of 1 ml·min−1 of isotonic saline was matched by the excretion in water ducks and when infusion of 0.4 ml·min−1 of 1,000 mosmolal saline was matched by the salt gland excretion in the salt ducks. After blood removal, AVT blood concentration (mean ±SE) increased from 6.5±0.4 to 8.4±0.6 pg·ml−1 in water ducks and from 18.1±1.6 to 22.6±1.9 pg·ml−1 in salt ducks. The respective blood osmolalities of 297.4±1.4 and 318.6±3.3 mOsm·kg−1 did not change. Reinfusion of the blood after steady-state conditions had been reattained decreased blood AVT from 7.9±0.7 to 6.7±0.5 pg·ml−1 in water ducks. In the salt ducks AVT concentration had already returned to the control level before blood reinfusion which induced no further reduction. The blood osmolalities remained unchanged in both groups. During blood removal and reinfusion, the excretion rate of the kidneys in water ducks and the salt glands in salt ducks were temporarily reduced and enhanced respectively, the effect being not symmetrical for salt gland secretion. For water ducks, the volume sensitivity of AVT release was found comparable to that of mammals, when related to the induced blood volume changes, the responses to blood removal and reinfusion being approximately equal in absolute terms. In the salt ducks, the volume sensitivity of AVT release was clearly expressed during blood removal but insignificant during blood reinfusion.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00585032
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