Twenty-five 30-month-old Lou rats fed a diet (6 g/100 g BW/day) containing 0.9% Ca and 0.8% Pi were divided into five groups.
View Article and Find Full Text PDFGen Comp Endocrinol
August 1994
Urinary output, urinary sodium and potassium excretion, plasma electrolyte concentrations and osmolality, plasma renin activity (PRA), and plasma aldosterone and arginine-vasopressin (AVP) concentrations were determined in eight camels in Tadla (Morocco). After administration of furosemide (2 mg.kg-1 body wt) urinary water, sodium and potassium excretions increased, inducing hypovolemia (as reflected by 14.
View Article and Find Full Text PDFEight dromedary camels were studied for 24 days under control conditions (3 days), and during water deprivation (14 days) and rehydration (7 days) in Tadla (Morocco), during the summer. During dehydration, food intake gradually fell and was zero on the last day and animals lost about 30% of their body weight. However, most of this reduction in weight was attributed to water loss, since body weight of the animals returned to control values following rehydration.
View Article and Find Full Text PDFThe relationship between experimental magnesium deficiency and blood pressure is complex and still the subject of much debate. The effect of Mg deficiency and blood pressure in Wistar rats receiving a Mg deficient diet (0.080 g/kg) for 40 weeks was examined.
View Article and Find Full Text PDFDiurnal changes in plasma ANF and AVP levels were investigated in four calves under standardized conditions. Both levels in plasma were measured at hourly intervals for 24 h along with arterial blood pressure, blood haematocrit, plasma cGMP, sodium, potassium, osmolality, proteins and albumin. Plasma ANF exhibited a first peak at mid-day while plasma AVP was low and a second peak at evening while plasma AVP was high.
View Article and Find Full Text PDFPlasma renin activity, plasma aldosterone and arginine-vasopressin concentrations were determined in five diarrhoeic and five healthy newborn calves. In animals suffering from diarrhoea these three parameters were 10-15 times higher than those observed in controls. These results suggest that the hormonal systems that control fluid and electrolyte homeostasis are highly stimulated by dehydration and salt depletion induced by faecal losses of water and sodium in calves affected with diarrhoea.
View Article and Find Full Text PDFThe effects of epinephrine (E), norepinephrine (NE), angiotensin II (AII), arginine-vasopressin (AVP) and endothelin on plasma ANP levels were studied according to a latin square design in six 12-21 days-old conscious Jersey calves weighing 30 +/- 4 kg. The animals chronically-instrumented with a carotid catheter for blood pressure recording, received at 11.00 a.
View Article and Find Full Text PDFArch Int Physiol Biochim Biophys
April 1991
The effects of normotensive and hypotensive hypovolaemia (haemorrhage) as well as isovolaemic hypotension (nitroprusside administration) on diastolic, systolic and mean arterial blood pressure, heart rate and plasma concentrations of arginine vasopressin were studied in two sets of experiments on 8-10 days old conscious newborn calves bearing an indwelling aortic catheter for continuous recording of arterial blood pressure. Removal of 20% of the estimated blood volume resulted in an average maximum decrease of systolic, diastolic and mean arterial blood pressure from 132 +/- 2 to 118 +/- 8 mm Hg (P less than 0.05), from 72 +/- 2 to 67 +/- 2 mmHg (P less than 0.
View Article and Find Full Text PDFInt J Sports Med
December 1989
To examine body fluid regulation over 72 h of recovery from a 24-h endurance race, changes in plasma volume (delta PV) and plasma aldosterone (A), cortisol (CO), antidiuretic hormone (ADH), and atrial natriuretic peptide (ANP) were studied in nine male runners before (C) and after (1-2 h = D0; 24 h = D1; 48 h = D2; 72 h = D3) the race, 24-h urine collections were made 1 week before (C), during the 24-h race/U0), and during the 3 days following the end of the race (U1, U2, and U3). On D0 delta PV decreased (2%). A, CO and ADH increased (380%, 200%, and 133%, respectively, from C values) and ANP decreased (68%).
View Article and Find Full Text PDFSystemic plasma concentrations of arginine vasopressin (AVP) were studied in three groups of 10-15 day-old conscious newborn calves. Animals in the first group (control group) and in the second group (systemic-hypertonic-injected group) received respectively isotonic and hypertonic (8 mmol NaCl/kg body weight) saline injection into the right jugular vein. Animals in the third group were fitted with chronic mesenteric and hepatic-portal catheters and received a 1 h-hypertonic saline infusion (2 mmol NaCl/kg body weight) into the main mesenteric vein.
View Article and Find Full Text PDFPlasma concentrations of atrial natriuretic peptide (ANP) were studied in eight adult non-pregnant cows and in two groups of six chronically catheterized bovine fetuses and their mothers in the eighth month of pregnancy. The first group of fetuses was used for studying the effect of an acute i.v.
View Article and Find Full Text PDFThe effects of synthetic atrial natriuretic factor (ANF) on the renin-aldosterone axis were studied in fifteen 4-7 day-old male milk-fed calves divided into 3 groups of 5 animals each. Synthetic ANF intravenous (i.v.
View Article and Find Full Text PDFPlasma concentrations of atrial natriuretic peptide (ANP), plasma renin activity (PRA), plasma concentrations of aldosterone, urine flow rate and sodium and potassium excretion were studied in two groups of four conscious 3-day-old male calves, infused with hypertonic saline or vehicle. Hypertonic saline infusion (20 mmol NaCl/kg body weight) was accompanied by a progressive rise in plasma concentrations of ANP (from 16.5 +/- 0.
View Article and Find Full Text PDFThe effects of synthetic Atrial Natriuretic Factor (ANF) on urine flow rate, sodium excretion, potassium excretion and arterial blood pressure were studied in 10-12 days-old female calves. In four female calves fitted with a Foley catheter, an intravenous administration of ANF (Ile-ANF 26; 1.6 micrograms/kg body wt during 30 min) induced an increase (P less than 0.
View Article and Find Full Text PDFAdrenocorticotropic hormone (ACTH) treatment (7 micrograms X kg-1 body weight) induced an increase in plasma aldosterone concentration in both Na-deficient heifers (following saliva loss after right parotid duct cannulation) and Na-replete heifers, but had no significant effect on plasma renin activity in either of these groups. The dopamine antagonist, metoclopramide, injected i.v.
View Article and Find Full Text PDFReprod Nutr Dev (1980)
February 1986
Aldosterone in ovine fetal circulation is mainly of fetal origin. Three of the renin-angiotensin system (RAS) parameters (renin, renin substrate and angiotensin II) originate in the fetus. The fetal RAS responds to stimulation (furosemide administration, hemorrhage, hypoxemia) or inhibition (phenylephrine or angiotensin II infusion) in a manner similar to that of the adult.
View Article and Find Full Text PDFReprod Nutr Dev (1980)
March 1983
Twenty primiparous Limousine ewes whose fetuses had been chronically catheterized in utero on day 120 of gestation were used. Plasma aldosterone levels were measured by radioimmunoassay during the last 15 days of gestation both in dams and fetuses, and during the first neonatal week in lambs. Aldosterone metabolic clearance rates in dams, fetuses and newborns were determined by continuous infusion of [1, 2, 6, 7-3H]-aldosterone.
View Article and Find Full Text PDFReprod Nutr Dev (1980)
March 1983
Aldosterone-binding to plasma proteins was determined in the guinea-pig by equilibrium dialysis, and the metabolic clearance rate (MCR) of aldosterone was calculated from experiments in which the labelled hormone was infused at a constant rate into the circulation during the neonatal period; no specific aldosterone-binding protein was found in the plasma. The hormone was weakly bound to the albumine. The MCR of aldosterone (1/day/100 g body weight) was unchanged from birth to day 8, and its values were similar to those found in adults.
View Article and Find Full Text PDFThe concentrations of corticosterone and aldosterone in the plasma and adrenal glands of foetal, newborn and mother mice were estimated during the last 4 days of pregnancy and throughout the perinatal period. The level of corticosterone in the maternal and foetal plasma fell from day 17 of gestation until birth, and then remained stable. Whereas the corticosterone content of the maternal adrenal glands did not change significantly, that of the foetal adrenal glands reached a peak on day 19 of gestation.
View Article and Find Full Text PDFPlasma and adrenal aldosterone concentrations have been estimated by radioimmunoassay and by gas phase chromatography in the foetus, the newborn and the mother between day 62 of pregnancy and day 8 of post-natal life. The pre-natal period is characterized by a gradual increase in plasma and adrenal aldosterone levels from day 62 up to 67. Birth greatly stimulates the synthesis and the release of aldosterone.
View Article and Find Full Text PDFC R Seances Soc Biol Fil
February 1978
Plasma aldosterone concentrations were measured by radioimmunoassay and metabolic clearance rates (M.C.R.
View Article and Find Full Text PDFC R Acad Hebd Seances Acad Sci D
December 1974
Ann Endocrinol (Paris)
October 1975