The effect of a meal of meat on glomerular filtration rate in dogs at normal urine flows.

O’Connor, W. J.; Summerill, R A

doi:10.1113/jphysiol.1976.sp011312

Cited by 90 publications

(51 citation statements)

References 10 publications

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“…This response is attributable to nitrogenous constituents of the diet since it was not observed after feeding meals low in protein [Shannon, Jolliffe and Smith, 1932;Pitts, 1935]. The increase in GFR observed in the present study when sheep on the LP diet received prolonged infusion of urea may resemble the postprandial increases described in the dog by O'Connor and Summerill [1976a] if the urea infusion promoted an increase in the quantity of protein passing to the abomasum and small intestine. The time taken for this response may well be prolonged since it is presumably the result of increases in microbial protein synthesis promoted by increased entry of urea into the reticulo-rumen as a result of the higher plasma concentrations of urea sustained by the infusion.…”

Section: Discussionsupporting

confidence: 57%

The Effects of Urea Infusion on Glomerular Filtration Rate and Renal Plasma Flow in Sheep Fed Low and High Protein Diets

Ergene¹,

Pickering²

1978

Exp Physiol

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Reducing the dietary N intake of sheep resulted in a significant fall in GFR with no change in RPF. Intravenous infusion of urea for 19-46 h had no effect on the high protein diet but on the low protein diet GFR and FF were increased to values approaching those observed on the high protein diet. On the low protein diet GFR was unaffected by infusion of urea for 4 h or of saline alone for 30 h. It is suggested that the observed changes in GFR are associated with changes in the quantity of protein passing to the abomasum and small intestine.In the previous paper Ergene and Pickering [1978] confirmed the reports of Gans and Mercer [1962] and Rabinowitz, Gunther, Shoji, Freedland and Avery [1973] that a fall in glomerular filtration rate (GFR) of sheep occurred when nitrogen intake was reduced. The fall in GFR resulted mainly from reduction in filtration fraction (FF), was associated with an approximately six-fold reduction in plasma urea concentration, and was unaffected by increasing the intake of sodium chloride.O 'Connor and Summerill [1976a, b] showed that the increase in GFR which occurred in dogs after a meal of meat was accompanied by increases in plasma urea concentration but that no increase in GFR occurred when similar increases in plasma urea concentration were produced by urea given by stomach tube. The present experiments were designed to investigate the possible association between plasma urea concentration and the changes in GFR of sheep induced by changes in nitrogen intake. Some of the results have been communicated to the Physiological Society [Ergene and Pickering, 1976]. METHODSSix Clun Forest ewes aged 3-5 yr and weighing 51-69 kg were housed in individual pens, allowed free access to water and to salt blocks (KNZ mineral salt licks: Pan Britannica Industries Ltd.) and fed once daily. Clearance studies were carried out in metabolism crates of the design described by Harrison [1974]. The high protein (HP) and low protein (LP) diets used were as described by Ergene and Pickering [1978] and provided respectively 18 5-20*5 gN and 8-3 gN per day. An acclimatization period of 10 days was allowed following change of diet before carrying out clearance procedures.The effects of short term infusion of urea were studied in four sheep on the LP diet in which urea was infused intravenously at 0X83 mmol. min-1 in sterile saline (9 g.1-1 NaCI) for 4 h with clearances measured during successive 20 min collection periods. The effects of more prolonged infusion were studied in three sheep on both LP and HP diets (see Table I). Intravenous infusion of urea at 0 33 mmol .min-1 in sterile saline (1 0 cm3. minm 1) was begun 77

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Section: Discussionsupporting

confidence: 57%

The Effects of Urea Infusion on Glomerular Filtration Rate and Renal Plasma Flow in Sheep Fed Low and High Protein Diets

Ergene¹,

Pickering²

1978

Exp Physiol

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“…The main route of excretion for antimonial drugs is via the kidney (16,27); therefore, the glomerular filtration rate influences how fast the drug can be cleared from the systemic circulation postdosing. In this study the calculated clearance rate for SSG solution is within the normal range for the glomerular filtration rate in the dog (24). Indeed, the clearance rates for all the SSG formulations were in this range.…”

Section: Discussionmentioning

confidence: 71%

Pharmacokinetics, Toxicities, and Efficacies of Sodium Stibogluconate Formulations after Intravenous Administration in Animals

Nieto

Alvar

Mullen³

et al. 2003

Antimicrob Agents Chemother

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“…Even when they had been for a fortnight on a 21 hr clock, immediately the clock was stopped their rhythms ran free with a period greater than 24 hr. All the evidence is thus that when subjects live on a 21 hr clock two rhythmic influences remain permanently operative, the one an endogenous circadian clock, the other the direct influences of their habits, such as the fall in body temperature 823 824 J. N. MILLS, D. S. MINORS AND J. M. WATERHOUSE on going to sleep, and the increased glomerular filtration rate (GFR) after a meal (O'Connor & Summerill, 1976 (Halberg & Katinas, 1973) is applied to the variance attributable to a circadian period expressed as a percentage of the total variance. When, as in the present study, two frequencies are present in the data, as shown by best-fitting sine curves, one can calculate a circadian amplitude ratio, as was attempted by Simpson et al (1970).…”

Section: Discussionmentioning

confidence: 99%

The physiological rhythms of subjects living on a day of abnormal length.

Mills¹,

Minors²,

Waterhouse³

1977

The Journal of Physiology

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4. On a 27 hr day two periods were less often present and a larger number of observed rhythms could be satisfactorily described by a single period, usually between 23 and 28 hr.5. In subjects spending a second week on a 21 hr day the circadian component was no less prominent than during the first week.6. When, after life on a 21 hr day, subjects were deprived of knowledge of time, there was evidence that the 21 hr component did not persist.7. The results are interpreted as evidence of the continuing existence of an influence with a period of around 24 hr, simultaneously with rhythmic influences resulting from the subjects' habits. On a 27 hr day there was sometimes evidence of entrainment, yielding an intermediate period.8. An attempt is made to compare the relative potency of the exogenous and of the persistent circadian influences on the several variables.

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The effect of a meal of meat on glomerular filtration rate in dogs at normal urine flows.

Cited by 90 publications

References 10 publications

The Effects of Urea Infusion on Glomerular Filtration Rate and Renal Plasma Flow in Sheep Fed Low and High Protein Diets

The Effects of Urea Infusion on Glomerular Filtration Rate and Renal Plasma Flow in Sheep Fed Low and High Protein Diets

Pharmacokinetics, Toxicities, and Efficacies of Sodium Stibogluconate Formulations after Intravenous Administration in Animals

The physiological rhythms of subjects living on a day of abnormal length.

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