Renal Response to Intravenous Phosphate Infusion in the Sheep

Fürst, Tomáš

doi:10.1071/bi9750511

Cited by 11 publications

(9 citation statements)

References 19 publications

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“…Ruminants fed roughage diets such as hay, straw or grass usually excrete very little phosphate in their urine and are more dependent on the gut than the kidney for major adjustments in phosphate balance (Scott, 1972;Clark, Budtz-Olsen, Cross, Finnamore & Bauert, 1973;Tomas, 1975;Towns, Boston & Lever, 1978). This is in contrast to the situation in non-ruminants in which the kidney is the major site of control.…”

Section: Introductioncontrasting

confidence: 47%

Mechanisms of phosphate transport in sheep intestine and parotid gland: response to variation in dietary phosphate supply

Shirazi-Beechey¹,

Beechey²,

Penny³

et al. 1991

Experimental Physiology

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SUMMARYThe transport of phosphate in intestinal brush-border membrane and parotid basolateral membrane vesicles isolated from sheep maintained on high and low phosphate diets have been studied. The mechanism of the transport of phosphate in the intestine is via a proton symporter whilst in the parotid gland it is effected by a Na+ coupled transporter. In sheep fed a low-P diet there is no change in the capacity of the parotid basolateral membrane to transport phosphate into the parotid end piece cells. This is in marked contrast to the response of the enterocyte brush-border membrane, where there is a significant enhancement of the capacity of the membrane to transport phosphate. We conclude that in sheep the gut appears to play a major role in response to phosphate deprivation, by increasing the capacity to transport phosphate. This enhancement is not achieved by increases in the levels of circulating 1,25-dihydroxycholecalciferol.

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Section: Introductioncontrasting

confidence: 47%

Mechanisms of phosphate transport in sheep intestine and parotid gland: response to variation in dietary phosphate supply

Shirazi-Beechey¹,

Beechey²,

Penny³

et al. 1991

Experimental Physiology

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“…1-1. Such levels are not far below what is considered to be the renal threshold for phosphorus excretion in sheep fed roughage diets (Watson, 1933;Clark et al 1973;Tomas, 1975) and in these conditions any further increase in plasma concentration might be expected to result in increased phosphorus excretion in urine. Whether this tendency towards high plasma phosphate levels indicates that they are less competent at regulating intestinal phosphorus absorption is, however, uncertain.…”

Section: Discussionmentioning

confidence: 99%

“…Sheep fed roughage diets such as hay, straw or grass usually excrete little phosphorus in their urine (Scott, 1969(Scott, , 1972Stacy, 1969;Clark, Budtz-Olsen, Cross, Finnamore & Bauert, 1973;Tomas, 1975;Towns, Boston & Leaver, 1978) and it is generally accepted that in these conditions major adjustments in phosphorus balance are dependent more on the gut than the kidney. Opinions differ, however, as to how within the gut this regulation is achieved.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Variation in Phosphorus Intake on Net Intestinal Phosphorus Absorption, Salivary Phosphorus Secretion and Pathway of Excretion in Sheep Fed Roughage Diets

Scott¹,

McLean

Buchan³

1984

Exp Physiol

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SUMMARYMature sheep fitted with rumen and duodenal cannulae and fed either pelleted hay or grass diets were given supplements of Na2HPO4 by continuous infusion into the rumen and the effects on salivary phosphorus secretion, intestinal phosphorus absorption and pathway of excretion were studied. Little phosphorus was excreted in the urine in control periods and little increase was seen in response to phosphorus supplementation, most of the extra phosphorus given being recovered in the faeces. Infusion of phosphorus into the rumen led to an increase in the flow of phosphorus to the intestine, an increase in absorption, a rise in plasma phosphate level and an increase in salivary phosphorus secretion while withdrawal of supplementary phosphorus was seen to have the opposite effects. In separate studies short sections of the upper small intestine temporarily isolated from the normal flow of digesta were perfused with solutions containing NaH2PO4 (5-50 mmol.1-1). Phosphorus absorption increased with increasing concentration though the relationship was curvilinear such that absorptive efficiency fell from around 0-7 at 5 mmol . 1-1 to around 0-35 at a concentration of 50 mmol. 1-1. The significance of these results in relation to the control of phosphorus balance in ruminants is discussed.

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“…Sheep and cattle fed concentrate diets in general seem to excrete much higher levels of phosphorus in their urine (Reed, Elliot & Topps, 1965;Topps, Reed & Elliot, 1966;Hyldgaard-Jensen, Whitelaw, Reid & Murray, 1966;Scott, 1972) than those fed roughage diets (Guegen, 1962;Scott, 1969Scott, , 1972Manston & Vagg, 1970;Clark, Budtz-Olsen, Cross, Finnamore & Bauert, 1973;Grace, Ullyat & MacRae, 1974;Tomas, 1975;Towns, Boston & Leaver, 1978;Grace, 1982) and in some circumstances this can lead to the formation of renal calculi (Bushman, Emerick & Embry, 1965;Hoar, Emerick & Embry, 1969;Rice & McMurray, 1981;Godwin & Williams, 1982). The reason for this phosphaturia is not entirely clear.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Feeding Either Roughage or Concentrate Diets on Salivary Phosphorus Secretion, Net Intestinal Phosphorus Absorption and Urinary Phosphorus Excretion in the Sheep

Scott¹,

Buchan²

1985

Exp Physiol

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SUMMARYMature sheep fitted with rumen and duodenal cannulae were fed either a hay or a concentrate diet and the effects on salivary phosphorus secretion, net intestinal phosphorous absorption and pathway for phosphorous excretion were examined. Route of excretion was markedly affected by diet with urine phosphorus levels being much higher and faecal levels lower when the concentrate diet was fed. This difference was not due to differences in phosphorus intake nor could it be related to differences in either plasma phosphorus levels or net intestinal phosphorus absorption. Salivary phosphorus secretion and renal tubular reabsorptive efficiency for phosphorus were, however, both lower when the concentrate diet was fed. The significance of these effects ofdiet in relation to the control ofphosphorus balance in ruminants is discussed.

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Renal Response to Intravenous Phosphate Infusion in the Sheep

Cited by 11 publications

References 19 publications

Mechanisms of phosphate transport in sheep intestine and parotid gland: response to variation in dietary phosphate supply

Mechanisms of phosphate transport in sheep intestine and parotid gland: response to variation in dietary phosphate supply

The Effect of Variation in Phosphorus Intake on Net Intestinal Phosphorus Absorption, Salivary Phosphorus Secretion and Pathway of Excretion in Sheep Fed Roughage Diets

The Effects of Feeding Either Roughage or Concentrate Diets on Salivary Phosphorus Secretion, Net Intestinal Phosphorus Absorption and Urinary Phosphorus Excretion in the Sheep

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