Available Online: http://www.ejpau.media.pl/volume4/issue2/veterinary/abs-03.html
RENIN - ANGIOTENSIN - ALDOSTERONE SYSTEM VERSUS OSMOTIC PRESSURE OF BLOOD PLASMA IN CALVES IN THE NEONATAL PERIOD
The aim of this work was to examine the influence of changes in plasma renin activity and aldosterone concentration on osmotic pressure of blood plasma in calves in the neonatal period. The examination was carried out on 11 calves of black white breed directly after birth and in the 2nd, 3rd, 7th and 30th day of life. Plasma renin activity and aldosterone concentration were examined by means of radioimmunological methods, while the osmotic pressure by means of the cryoscopic method. The decrease of plasma renin activity to the value of 1,55 ng/ml/h was proved in the first week of life, and it remained at this level till the end of the first month of calves life. The aldosterone concentration was high after birth (61pmol/l) and decreased rapidly during the first 24 hours. Gradual increase of concentration of this hormone (to 85 pmol/l) was observed from the 2nd to the 7th day, and its decrease till the end of the first month of life. The
Key words: calves, neonatal period, plasma renin activity, aldosterone, osmotic pressure.