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Biomedical subjects

E Payne

Publications and source records attributed to E Payne.

At least 19 recordsLinked to original sources
PubMed1992

The metabolism of noradrenaline in the sheep and the effect of dry matter intake upon the production of a metabolite, urinary vanillylmandelic acid.

1. The metabolism of noradrenaline was investigated in the sheep using 3H-noradrenaline injected subcutaneously or intravenously. 2. Analysis of urine collected over 24 hr showed that the bulk of 3H-noradrenaline was rapidly degraded and excreted via the urine. The principle metabolite was the conjugated amine as well as monohydroxy phenyl glycol and vanillylmandelic acid (VMA) previously reported for the rat. 3. Urinary VMA from lambs of two breeds noted for differences in fat (Southdown and Suffolk) increased curvilinearly with dry matter intake and there was a significant breed difference in regression with intake. 4. It is feasible that differences in noradrenaline production could contribute to differences in body composition between breeds.

Animals↗
PubMed1991

Studies on the role of liver cytochrome P-450 and oestradiol metabolism in the effects of nutrition and phenobarbital on ovulation rate in the ewe.

Coopworth ewes were differentially fed to produce 60 heavy (62 kg) and 80 light (45 kg) ewes. They were then fed a low protein (100 g protein kg-1 dry matter) pelleted ration. On Day 7 of the oestrous cycle after synchronization the following treatments were commenced in groups of 10 ewes: 4 low liveweight groups received low protein (LP), high protein (HP; 230 g protein kg-1 dry matter), LP + phenobarbital (PB; 1 g per os per day in gelatin capsules for 10 days) and LP + triacetyloleandomycin (TAO, 0.5 g day-1 in capsule for 10 days); while 3 high liveweight groups received LP, HP and HP + carbon tetrachloride (CCl4, 0.1 mL kg-1 bodyweight as a single dose). The experiment was repeated using another 7 groups of 10 ewes at an interval of 3 weeks. PB, TAO, high liveweight, and protein diet increased the ovulation rate whereas treatment with CCl4 reduced the ovulation rate. Because of the small number of ewes in some treatment protocols, only changes due to liveweight and protein diet were statistically significant. Liver weight and microsomal protein were increased by all treatments except CCl4 which caused a decrease. PB and TAO increased cytochrome P-450 and associated enzyme activities, in particular those related to cytochrome P-450p or P-450NF (including oestradiol 2-hydroxylation) in the human liver. In vitro, TAO binding indicated that the specific cytochrome was induced by PB and TAO but there were no direct effects of protein diet and liveweight. Most of the data support the theory that nutritionally induced increases in ovulation rate in ewes could result from changes in oestradiol metabolism, but the lack of induction of the specific cytochrome by protein diet and high liveweight suggests that increased ovulation caused by these factors may be the physiological response to several metabolic changes.

Animal Nutritional Physiological Phenomena↗
PubMed1990

Postnatal development of striatal neurotensin immunoreactivity in relation to clusters of substance P immunoreactive neurons and the "dopamine islands" in the rat.

Conventional immunoperoxidase preparations of the coronally sectioned brains of rats killed at various times during the early postnatal period revealed the distributions of tyrosine hydroxylase, substance P, and neurotensin immunoreactivities. At birth, patches of dense tyrosine hydroxylase immunoreactivity were present across the breadth of the rostral striatum, whereas patches displaying substance P immunoreactivity were present only in its lateral half, appearing in its medial half by about postnatal day 3. Neuronal neurotensin immunoreactivity was absent in the rostral striatum at birth, although some neurotensin immunoreactive cells were present in the tail of the caudate-putamen. Rostrally, neurotensin immunoreactive cells appeared first along the lateral margin of the caudate-putamen on postnatal day 3, became numerous there about day 5, spread medially into the striatum by day 7, and achieved their medialmost distribution by about day 10. Their numbers and those of substance P immunoreactive neurons diminished thereafter. Substance P immunoreactive patches, which contained numerous labeled neurons and "puncta," shared coextensive distributions with patches of dense tyrosine hydroxylase immunoreactivity, but interdigitated with neurotensin immunoreactive cell clusters. The neurotensin immunoreactive cell clusters lacked puncta, the light microscopic representation of axon terminals, or swellings. It is concluded that the patchy infrastructure of the striatum, which is established prior to birth, is substrate for the progression of separate "waves" of elevated neuronal peptide content, one reflecting substance P and a later one reflecting neurotensin. These proceed along rostromedialward trajectories to involve interdigitating neuronal domains.

Aging↗
PubMed1976

The efficacy of protein supplementation in overcoming urea toxicity in sheep.

1. In the first experiment sheep taken from pasture were given a low-protein diet for six weeks in individual pens. Then, for 1 week, groups were given a supplement of lucerne chaff, safflower meal or lucerne chaff plus safflower meal. In the second experiment eighteen sheep maintained on lucerne chaff rather than pasture were then depleted of protein to a greater extent by feeding on a restricted low-protein diet. Six of the sheep received a supplement of molasses throughout the period of protein depletion while six of the sheep on the basal ration received a supplement of safflower meal after 6 weeks on the low-protein diet. 2. The urea tolerance of the sheep, is indicated by blood ammonia levels after oral dosing with aqueous solutions of urea, was determined after the period of supplementation. "Arginine synthetase" activity (combined activities of argininosuccinate synthetase (EC 6.3.4.5) and argininosuccinate lyase (EC 4.3.2.1) was determined in liver samples obtained by biopsy at various intervals during the experiment. 3. Supplementation for 7 d with 73 g crude protein (nitrogen X 6-25)/d increased the tolerance to urea as indicated by reduced blood NH3 levels, and also increased "arginine synthetase" activity. 4. Giving supplements of molasses delayed the onset of urea toxicity but not the extent of toxicity. 5. It is suggested that short-term feeding of protein concentrates to sheep before giving urea supplements can increase their tolerance to urea.

Ammonia↗
PubMed1976

Bovine plasma corticoids during parturition.

Concentrations of adrenal corticoids in plasma were determined by a competitive protein-binding technique using jugular blood samples taken three times daily and more frequently during labor from 21 cows before and after parturition. The prepartum value was 6 ng/ml with a sharp rise during the last 16 h before calving. The average value at the time of calving was 19.2 ng/ml with a significant drop 1 h after calving to 11.2 ng/ml and a return to basal concentrations by 3 days postpartum. Evidence that labor is responsible for the increased corticoid is given. Maternal cortisol at calving was correlated with the time taken to calve .23, calf cortisol .04, cow:calf weight ratio -.07, and calf weight .14.

Animals↗
PubMed1975

Radioimmunoassay of 13, 14-dihydro-15-keto prostaglandin F in bovine peripheral plasma.

A radioimmunoassay has been developed for 13, 14-dihydro-15-keto-prostaglandin F in bovine peripheral plasma. Acidified plasma samples were extracted with diethyl ether and the dried extract assayed for 13, 14-dihydro-15-keto-prostaglandin F using antiserum raised against a 13, 14-dihydro-15-keto-prostaglandin F2alpha-albumin complex. The tracer used for the assay was prepared enzymatically from tritiated prostaglandin F1alpha. Polyethylene glycol was employed to separate free and bound 13, 14-dihydro-15-keto-prostaglandin F. The inter-assay coefficient of variation based on 9 determinations of control plasma was 13.8%. The detection limit of the assay was 25 pg 13, 14-dihydro-15-keto-prostaglandin F/ml plasma. In 3 cows around estrus there was a complex sseries of peaks of 13, 14-dihydro-15-keto-prostaglandin F concentrations coincident with luteolysis and declining progesterone concentrations. Changes in peripheral plasma concentrations of 13, 14-dihydro-15-keto-prostaglandin F in the pregnant cow near term showed a close correlation with prostaglandin F levels in utero-ovarian venous plasma. The concentration of 13, 14-dihydro-15-keto-prostaglandin F in 12 men was 114 +/- 20 pg/ml plasma. It is concluded that the measurement of peripheral 13, 14-dihydro-15-keto-prostaglandin F concentrations may offer a simple and convenient method for monitoring uterine prostaglandin F production in the cow.

Animals↗
PubMed1975

Hormonal changes around bovine luteolysis.

Plasma concentrations of estradiol-17beta, progesterone, LH and 13, 14-dihydro-15-keto-PGF2alpha were determined by radioimmunoassay on 2-hourly samples obtained around luteolysis and estrus in three dairy cows. The decline in progesterone occurred before the preestrous rise in estrogen and no pre-estrous peak of progesterone could be detected. The major activity of prostaglandin coincided, with declining progesterone levels and the active stage of estrogen secretion.

Animals↗