mesotocin and Poultry-Diseases

1. The effect of 96 hrs of water deprivation on plasma electrolytes, osmolarity, arginine vasotocin (AVT), mesotocin (MT), and on AVT and MT content in the neurohypophysis, anterior hypothalamic area (AHA) and proventriculus, was studied at 24 hrs intervals, in adult White Leghorn cockerels. 2. Plasma AVT increased three fold during the first 24 hrs but there was no further change during the next 48 hrs. In the last 24 hrs, plasma AVT decreased in about 25%. Plasma MT did not change during the entire period of dehydration. 3. Plasma sodium and osmolarity gradually increased during that time. 4. Neurohypophysial AVT content was depleted by 95% during the period of dehydration while MT content did not change. 5. In the AHA there was no change in AVT levels during dehydration while the levels of MT increased while in the proventriculus there was no change in either AVT or MT levels. 6. For the data collected during the entire experimental period, no correlation was found between plasma osmolarity and plasma AVT, but there was a highly significant negative correlation between plasma osmolarity and neurohypophysial AVT content. 7. It may be suggested that the depletion in AVT content in the neurohypophysis during progressive water deprivation resulted in an insufficient level of AVT in circulation to enable the cockerels to counter the dehydration. This may explain the death of those cockerels which were dehydrated for a further 24 hr period.

Topics: Animals; Chickens; Dehydration; Hypothalamus, Anterior; Male; Oxytocin; Pituitary Gland, Posterior; Poultry Diseases; Proventriculus; Vasotocin; Water Deprivation

1. Renal tissue blood flow (renal perfusion) and plasma levels of arginine vasotocin (AVT) and mesotocin (MT) were measured in anesthetized chickens before and during hemorrhage. 2. Renal perfusion did not decrease (P less than 0.05) until nearly 50% of the blood volume had been removed. The decrease in renal perfusion was not related to arterial blood pressure but was concomitant with an increase (P less than 0.05) in plasma AVT levels. 3. Renal perfusion during hemorrhage was positively correlated with plasma MT levels by the regression equation: renal perfusion = 0.091 (MT)-1.1459 which was highly significant (P less than 0.001, r2 = 0.95). 4. The results of this study suggest that MT as well as AVT may participate in regulating blood flow in the avian kidney.

Topics: Animals; Chickens; Hemodynamics; Hemorrhage; Kidney; Male; Oxytocin; Poultry Diseases; Vasotocin