Renin-aldosterone axis and arginine-vasopressin responses to sodium depletion in camels.

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.

Rat myoblast fusion requires exteriorized m-calpain activity.

Our previous studies demonstrated that fibronectin could be proteolyzed by m-calpain during muscle cell differentiation. Recent results indicated also that m-calpain could be exteriorized and more particularly associated to extracellular matrix components. To clarify one of the possible physiological functions of this proteinase during myogenesis, we have analyzed the incidence of added purified m-calpain and calpain inhibitors on the fusion kinetics of cultured myoblasts.

Hormonal control of water and sodium in plasma and urine of camels during dehydration and rehydration.

Eight 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.

Renin-aldosterone system and arginine vasopressin in diarrhoeic calves.

Plasma 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.

Plasma adrenocorticotrophin, cortisol and aldosterone responses to ovine corticotrophin-releasing factor and vasopressin in sheep.

Ovine corticotrophin-releasing factor (oCRF) (1 microgram/kg) and arginine vasopressin (AVP) (1 microgram/kg) were injected iv in sheep, both separately and in combination. Plasma levels of immunoreactive ACTH (IR-ACTH), cortisol, and aldosterone were measured for 3 h after the injections. Mean levels before injections were 8 +/- 4 pmol/l for ACTH, 7 +/- 3 nmol/l for cortisol, and 28 +/- 9 pmol/l for aldosterone.

Urinary sodium excretion and the renin-aldosterone system in new-born calves.

Urinary Na+ and K+ excretion, plasma aldosterone levels (PAL) and plasma renin activity (PRA) were measured in three groups of four 3-day-old calves infused with aldosterone, ethacrynic acid and hydrochlorothiazide or with vehicle. Aldosterone infusion (16.7 micrograms/kg body wt.

Lack of effect of metoclopramide on plasma aldosterone concentrations in young calves.

In five 10-day-old Holstein X Friesian male calves, the intravenous injection of the dopamine blocker metoclopramide (1 mg/kg bwt) had no significant effect on plasma aldosterone concentration. Plasma sodium, potassium, cortisol, corticosterone concentrations and plasma renin activity measured in these animals during 120 min following metoclopramide injection were never significantly different from those simultaneously measured in 5 control calves.

Control of aldosterone secretion in domestic mammals during the perinatal period.

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.

Electrolyte balance, mode of delivery and plasma aldosterone levels in newborn lambs.

Plasma aldosterone, sodium (Na) and potassium (K) concentrations, daily Na and K intakes, and urinary and faecal excretion were measured during the first week of postnatal life in 9 lambs naturally born at term (145 days of gestation) and in 10 lambs delivered by caesarean section on day 145 (6 lambs) or on day 139 (4 lambs) of gestation. Plasma aldosterone, Na and K concentrations showed no significant variation during the experimental period in any group of lambs, and there was no significant difference concerning these parameters among the three groups. Na and K balances were always positive during the experimental period in naturally born lambs.

ACTH and plasma corticosteroid levels in young calves.

1. Plasma sodium, potassium, aldosterone and cortisol levels were measured in seven 11-day-old calves after ACTH infusion and in five control animals. 2.

Sodium and potassium balances and plasma aldosterone levels in newborn calves.

This paper describes a balance study, performed during the first 7 days of postnatal life on 10 male Holstein x Friesian calves born spontaneously at term. The relationship between sodium and potassium balances and plasma aldosterone levels were assessed during the postnatal period. The animals were put in metabolic cages immediately after birth for 7 days.

Sodium and potassium in blood and milk and plasma aldosterone levels in high-yield dairy cows.

Plasma sodium, potassium and aldosterone levels, daily milk production and milk sodium and potassium were measured in 10 Holstein X Friesian cows during a whole lactation period beginning in November and ending in November the following year. The milk production (4 p. 100 fat content) of these animals was 6 170 +/- 66 kg (mean +/- SEM).

Plasma sodium, potassium and aldosterone levels in newborn calves.

1 Plasma sodium, potassium and aldosterone levels were measured in 11 calves during the first postnatal week. 2 Plasma sodium and potassium levels showed no significant variation between birth and the seventh day of postnatal life. 3 A sharp decrease in plasma aldosterone levels was observed between birth (119 +/- 7 pg/ml) and 12 hrs (25 +/- 8 pg/ml).