Regulation of water and electrolyte metabolism during dehydration and rehydration in camels

The present study was undertaken to examine the effect of severe dehydration and rapid rehydration in electrolytes and body fluids homeostasis on the arabian camel (Camelus dromedarius), and to find out which pathway is responsible for the secretion of aldosterone in the dehydrated camel; either the renin-angiotensin axis or ACTH axis. In the first experiment ten dromedary camels were studied for a total of 29 days; 7 days under control conditions, 15 days of water deprivation and 7 days of rehydration in Bureidah (Saudi Arabia) during summer, 1996. Plasma electrolyte concentrations, plasma osmolality, packed cell volume (PCV), blood hemoglobin concentrations, plasma concentrations of glucose, creatinine, blood urea nitrogen (BUN), total protein, plasma renin activity (PRA), angiotensin II, aldosterone, arginine-vasopressin (AVP), adrenocorticotropic hormone (ACTH) and cortisol concentrations were determined during both periods. During the second trial adrenocorticotropic hormone (ACTH) and enalapril, an angiotensin-converting enzyme inhibitor (ACE-I), were utilized in two separate experiments during dehydration and control (hydration) periods. Enalapril (0.2 [mu]g/kg) induced a sharp decrease in plasma (Na+] and an increase in plasma (K+] concentrations (P \u3c 0.05) in the dehydrated camels but not in the control camels;Plasma osmolality decreased significantly in both dehydrated and control camels after ACE-I administration. ACE-I induced a sharp decrease in plasma angiotensin II and aldosterone concentrations (P \u3c 0.05) in the dehydrated camels. In the control camels however, ACE-I induced a decrease in plasma aldosterone concentrations but not in plasma angiotensin II. Plasma renin activity (PRA) increased significantly in the dehydrated camels. In the second experiment, 0.4 IU/kg ACTH administration had no significant effect on plasma electrolytes and osmolality on the dehydrated and control camels. The administration of ACTH induced a sharp increase in plasma cortisol concentrations in the dehydrated and control camels. Plasma aldosterone concentrations however, increased only in the dehydrated camels. The present study clearly shows that both angiotensin II and ACTH stimulate aldosterone secretion during dehydration in camels. However, due to the parallel increase in PRA, plasma angiotensin II and plasma aldosterone in dehydrated camels without any parallel changes in plasma cortisol or ACTH, the effect of angiotensin II on aldosterone secretion seems to be dominant over ACTH

Erythrocyte osmotic fragility and blood indices in the one-humped camel (Camelus dromedarius) : correlations with age and sex

http://www.worldcat.org/oclc/3400175

ELMOUGHJARVMVol2No304

ABSTRACT The ameliorative activity of aqueous extracts of the flesh and pits of dates (Phoenix dactylifera L.) on carbon tetrachloride (CCl 4 )-induced hepatotoxicity was studied in rats. Sixty male Wistar rats were divided into six equal groups of 10. Four groups received extracts of flesh or pits of Phoenix dactylifera and intraperitoneal (IP) CCl 4 (0.2 ml/100 g) either before or after administration of flesh or pits. Two groups were controls, one treated with CCl 4 and one with only saline. Liver damage was assessed by liver morphology, histology, and estimation of plasma concentration of bilirubin and enzyme activities of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase. Treatment with aqueous extract of date flesh or pits significantly reduced CCl 4 -induced elevation in plasma enzyme and bilirubin concentration and ameliorated morphological and histological liver damage in rats. This study sug