Blood Plasma Of Sheep Research Articles

Amine oxidase enzymes of sheep blood vessels and blood plasma: A comparison of their properties

1. A comparison between the biochemical properties of semicarbazide-sensitive amine oxidase (SSAO) activities has been made in sheep blood plasma and arterial wall. 2. The metabolism of benzylamine (BZ) by blood plasma was resolved into high affinity ( K) m 2.76 ± 0.24 μM) and low affinity ( K m 743 ± 49 μM) activities. Spermidine metabolism was by a single component ( K m174 ± 22 μM) and this amine reduced the metabolism of high concentrations of BZ. 3. A single component metabolised BZ in arterial homogenates ( K m 11.3 ± 1.3 μM) and which metabolised Spermidine at a very slow rate. 4. Dopamine was deaminated by plasma SSAO and competed with both low and high concentrations of BZ. Dopamine also interfered with arterial metabolism of BZ. 5. These results suggest that there are two SSAO enzymes in sheep blood plasma, with one having similar properties to SSAO in the arterial wall.

Physiological and pathological influences on sheep blood plasma amine oxidase: Effect of pregnancy and experimental alloxan-induced diabetes mellitus

A copper-containing amine oxidase is present in sheep blood plasma and has a high capacity to deaminate spermine and spermidine. The physiological function of this enzyme remains to be determined. Sheep blood plasma amine oxidase ( spao) was measured by its ability to deaminate spermidine (700 μM) using a peroxidase-linked colorimetric assay developed for microtitre plates. srno activity has been studied in a group of Welsh Mountain sheep with experimental alloxan-induced diabetes. This resulted in an increase in srno activity which reached a peak of 70 days after alloxan treatment (60 per cent increase). This change could be seen in both pregnant and non-pregnant diabetic sheep. In normal pregnant ewes, spao activity remained stable for the first 100 days of pregnancy but declined by 50 per cent in the last month of pregnancy. Together, these findings suggest that spao activity is controlled by hormonal influences. This sensitive and convenient assay method could provide clues as to the physiological significance of spao and may be a useful clinical chemical indicator in the sheep.

Food deprivation suppresses stress-induced rise in catabolic hormones with a concomitant tendency to potentiate the increment of blood glucose

The organism of a food-deprived animal is directed toward minimizing energy expenditure and plasma levels of catabolic hormones and glucose are also reduced. Stress, on the other hand, is associated with enhancement of metabolic processes, elevated plasma catabolic hormones, and higher glucose levels. The question arises as to whether food deprivation may be able to attenuate the rise of plasma catabolic hormones seen in stress. For this purpose the variations in triiodothyronine (T 3), thyroxine (T 4), cortisol and glucose in blood plasma of sheep were monitored during 101 hr of food deprivation and 5 hr of stress. Stress was evoked by isolation of individual sheep from the flock. Blood was sampled by venipuncture once a day during 4 days preceding the isolation stress. On the day of isolation, blood was taken 4 times at 1.5- to 2-hr intervals. Food deprivation lowered the T 3, T 4 and glucose levels to 45.0, 59.5 and 78.0 percent of the basal level, respectively. Plasma cortisol level did not change over the fasting period in sheep not having visual contact with fed animals. Maintaining such a contact elevated cortisol level maximally by 139 percent over basal level. This indicates that the involvement of an emotional factor seems to be necessary for manifestation of stress. Isolation stress acting on fed and fasting sheep increased all measured hormones and glucose levels. However, in fed sheep, the maximal levels of T 3, T 4 and cortisol were 72.5, 48.4 and 50.0 percent higher than in corresponding isolated and food-deprived animals. Inversely, the maximal concentration of plasma glucose was about 16.6 percent higher in food-deprived than in fed animals. The mean Δ increase of hormones and glucose at 1, 3 and 5 hr of stress was lowered (T 3, cortisol), equal to (T 4), or higher (glucose) than in food-deprived animals. Increased frequency of venipuncture elevated the plasma T 3 and glucose levels in nonisolated food-deprived sheep, despite a tendency to suppress plasma cortisol. However, unlike glucose, the elevated plasma T 3 never achieved the basal level noted before the onset of food deprivation. This suggests that food-deprived animals possess a mechanism which suppresses the stress-induced rise of catabolic hormones, saving energy expenditure. In conclusion, the present experiment suggests that food deprivation attenuates a stress-induced increase in catabolic hormones like T 3 and cortisol, and potentiates the increment of blood glucose during isolation, probably by a decreased utilization rate.

Comparative levels of free and conjugated plant estrogens in blood plasma of sheep and cattle fed estrogenic silage

Plasma concentrations of the plant estrogens formononetin, daidzein, and their metabolite equol were determined in blood samples from dairy cattle and sheep, fed on red clover/grass silage. The results suggest tha the differences in sensitivity, described in the literature, between cattle and sheep to plant estrogens are certainly not caused by differences in their capacity to detoxify the estrogenic compounds

Vitamin E concentrations in blood plasma of sheep and in sheep tissues after a single intraruminal or intraperitoneal administration of DL-α-tocopheryl acetate

Twenty-five yearling wethers, weighing 40 to 45 kg were used in a trial designed to compare the effect of the route of administration of vitamin E upon plasma and tissue vitamin E status. Five control sheep without vitamin E administration were killed at the beginning of the trial. Of the remaining 20 sheep, 10 were given DL-alpha-tocopheryl acetate intraruminally and 10 by intraperitoneal injection. Of these, 10 wethers were killed three days after dosing (five from each treatment, IR3 and IP3) and the remaining wethers were killed eight days after dosing (IR8 and IP8). Blood samples were taken throughout the trial from sheep on the IR8 and IP8 treatments. Samples of whole adrenal gland, heart, liver, kidney, brachiocephalicus muscle, lung, pancreas and spleen were taken from all sheep at slaughter and were analysed for their vitamin E content. The blood plasma results showed that the most important index of vitamin E bioavailability, the area under the plasma concentration versus time curve, was greater in the intraperitoneally than intraruminally dosed sheep. There was a higher concentration of vitamin E in the tissues from the intraperitoneal group than the intraruminal group three days after the intraperitoneal injections. The results suggest that the greatest responses in vitamin E concentration in plasma and the tissues were recorded in sheep following intraperitoneal rather than intraruminal dosing with DL-alpha-tocopheryl acetate.

Improved estimates of clearance of 131I-labelled insulin-like growth factor-I carrier protein complexes from blood plasma of sheep

Clearance of protein-bound forms of insulin-like growth factor-I (IGF-I) from the circulation of sheep was determined using single injections of 131I-labelled ovine or [Thr59]-human IGF-I, in the 'free' form or prebound to 50 or 150 kDa plasma binding protein fractions. The half-life of circulating protein-bound forms of IGF-I was determined by size-exclusion chromatography of plasma samples taken over a 24- to 26-h experimental period. IGF-I bound to lower molecular weight binding protein(s) (approximately 50 kDa) showed a half-life of 26-40 min (mean 34 min; n = 6), while the half-life of a high molecular weight fraction (150 kDa) was considerably longer (range 398-603 min; mean 545 min; n = 8). Metabolic clearance of IGF-I following administration of free tracer ranged from 3.0 to 5.3 ml/min in sheep (n = 4) weighing 26.0-28.5 kg. Tracer distribution volume was 59 ml/kg liveweight (n = 4). Tracer degradation products were first detected in plasma 8 h after i.v. administration. No differences in stability of the purified ovine and recombinant human IGF-I tracer preparations were observed. However, a fraction of the [Thr59]-IGF-I tracer did not possess binding activity and this was associated with excretion of a greater proportion of administered radioactivity (over 22 h) in urine in animals receiving [Thr59]-IGF-I tracer (18.4-19.3%) compared with ovine IGF-I (7.1-11.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of shearing on the concentration of cortisol and thyroid hormones in the blood plasma of sheep.

The effect of shearing on the concentration of cortisol and thyroid hormones in the blood plasma of sheep.

Intestinal Absorption of Fatty Acids, and Blood Lipid Composition in Sheep

Interrelationships between intestinal uptake of fatty acids and their concentrations in lipids of blood plasma of sheep were assessed by quantities of individual fatty acids that flowed through and were absorbed from the intestinal tract under different dietary conditions.Major long-chain fatty acids were approximately 90% digested, thus demonstrating that dietary fatty acids of high melting points can be absorbed efficiently by ruminants provided they are well dispersed.Relationships were linear between uptakes of 16:0, 18:0, 18:1, and 18:2 fatty acids from the gut and their concentrations in both triglycerides and triglyceride-free plasma lipids. The proportion of each transferred to triglyceride-free plasma lipids was in order 18: 2>18:1>16:0>18:0, whereas in plasma triglycerides the order was 16:0 = 18:0 = 18:2<18:1. Interconversion of 18:0 to 18:1 by intestinal mucosa may explain the anomalous behavior of 18:1 triglycerides.These results are consistent with the hypothesis that the intrinsic nature of the fatty acid primarily determines the composition of triglyceride-free plasma lipids whereas the relative amount of each acid absorbed by the intestine determines that of plasma triglycerides and, hence, of milk and depot fats of ruminants.

The influence of anaesthesia on the concentrations of progesterone and cortisol in peripheral blood plasma of sheep

Levels of progesterone and cortisol were measured in the peripheral plasma of sheep subjected to barbiturate (sodium pentobarbitone) and gaseous (halothane) anaesthesia both alone and in combination. Significant increases were recorded inthe level of cortisol in all experiments and in the levels of progesterone in all experiments except that involving halothane alone. It was also found that the cortisol levels remained elevated for a greater period of time than those of progesterone.

Effect of salt water ingestion on pregnancy in the ewe and on lamb survival

The addition ot sodium chloride, to provide concentrations of 1.0 and 1.3?, to the drinking water of pregnant ewes caused distress at parturition to some of the ewes and neonatal mortalities in their lambs. The effects were more evident in older sheep (aged 7 years) than in younger (3-year-old) animals and were associated, in general, with ewes which carried twin lambs. Progesterone levels in the blood plasma of sheep were higher in twin-bearing ewes than in ewes with single lambs, both for control ewes drinking fresh water and for ewes drinking saline. Drinking 1.3% saline augmented the increase in progesterone levels in older ewes bearing twins. Cortisol levels were normal in all ewes.Plasma levels of potassium and chloride were significantly higher and calcium and magnesium levels lower in pregnant ewes which received saline.It is suggested that the adverse effects of salt water ingestion in twin-bearing pregnant ewes could be due to an excessive retention of potassium and chloride, brought about by a disturbance of normal sodium homeostatic mechanisms associated with the pregnant state of the animals.

A solid-phase radioimmunoassay for ovine follicle-stimulating hormone.

SUMMARY A radioimmunoassay using antibody-coated polystyrene tubes is described, which is suitable for the estimation of follicle-stimulating hormone (FSH) levels in sheep blood plasma. Ovine FSH was labelled with 125I by an enzymic method employing lactoperoxidase and H2O2, and was stable for several months at −15 °C. Antisera to ovine FSH were raised in rabbits. Standard curves for unlabelled FSH obtained by this method with different preparations of labelled FSH showed reproducible slopes from day to day. Ovine luteinizing hormone (LH) and thyroid-stimulating hormone (TSH) showed about 17% cross-reaction in the assay, necessitating the application of a correction to the FSH values for samples of plasma containing more than 15 ng of LH or TSH/ml. The FSH content of plasma from wethers and anoestrous ewes ranged from 20 to 120 ng/ml.

Factors limiting the intake of feed by sheep. VII. The digestion of a medium quality roughage and the effect of post-ruminal infusion of casein on its consumption by young sheep

Feed intake and digestion studies were conducted with sheep offered a medium quality roughage which contained, on a dry matter basis, 33.4% of acid detergent fibre and 10.3 % of crude protein. The roughage had an organic matter (OM) digestibility of 57%. The quantity of OM apparently digested in the stomach was equal to 63 % of the OM digested in the alimentary tract, and 80% of the digestion of the dietary fibre took place in the stomach. The quantity of nitrogen in forms other than ammonia that left the stomach in digesta was similar to the dietary nitrogen intake and the apparent digestibility of this digesta nitrogen in the intestines was 66%. Approximately 13 g of crude protein was digested in the intestines per 100 g digestible OM intake. The values of parameters relating to the movement of digesta through the stomach were within the ranges expected with roughage diets. The levels of essential acids in the peripheral blood plasma of sheep given the roughage ad libitum were comparatively low; the values for the total essential amino acids ranged from 85 to 105 pmoles/100 ml and varied with the time of day. The voluntary consumption of roughage by young sheep (8-9 months of age) was 66 g OM/day/(kg body eight)0.75, an intake that did not permit the animals to obtain sufficient energy to express their growth potential. Post-ruminal infusion with casein (34-39 g/day), although increasing the amount of crude protein digested in the intestines (DCP1) by about 30%, failed to increase voluntary feed consumption or rate of body growth. Accordingly voluntary feed consumption and body growth were not limited by the availability of essential amino acids at the tissue level. It was concluded that the voluntary feed consumption and rate of body growth in young sheep would not be limited by the supply of essential amino acids at the tissue level with diets providing 13 g or more of DCP1 per 100 g digestible OM-the equivalent of about 49 g DCP1/Mcal net energy.

The Fate of Intravenous Doses of Free and Plasma Protein-Bound [35S]Cystine in the Sheep

When a tracer quantity of L- or DL.[35S]cystine was mixed with sheep blood plasma about two-thirds of the radioactivity was bound to the proteins after 4 hr at 39�C, probably as half. cystine residues in disulphide linkage. The reversibility of the binding was demonstrated.