The function of the mammalian mesonephros

Stanier, Margaret W.

doi:10.1113/jphysiol.1960.sp006452

Cited by 24 publications

(17 citation statements)

References 9 publications

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“…In the 45-day foetuses the urinary urea concentrations were somewhat higher and the chloride concentrations much lower than those found in the bladder contents of the 45-day foetuses of the slaughter-house material previously reported (Stanier, 1960). There may in the latter have been some diffusion of solutes across the bladder wall in the direction of equilibrium with the peritoneal fluid, a process which has been described in the thickerwalled bladder of the adult dog (Levinsky & Berliner, 1959).…”

Section: Resultsmentioning

confidence: 72%

“…The finding that the urea concentrations in the newly-formed urine of the 44-46 day foetuses were somewhat higher than the concentrations in the 'static' bladder urine at this age previously (Stanier, 1960) prompted us to measure the chloride concentration of the flowing urine also. Eight urine specimens collected during the flow-rate studies on these younger foetuses showed concentrations of chloride ranging from 13 to 33 m-equiv/l., as compared with an average of 96 m-equiv/l.…”

Section: Resultsmentioning

confidence: 99%

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The rate of flow of urine of foetal pigs

Perry¹,

Stanier²

1962

The Journal of Physiology

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Observations on the urine found in the bladders ofpig foetuses at a stage of gestation when the mesonephros is present and active suggested that its composition, except for the absence of glucose, resembles an ultrafiltrate of foetal serum (Stanier, 1960). The material for these observations was obtained from the slaughterhouse, and the fluid was removed from the foetal bladders as soon as possible after the slaughter of the sow, and with minimal alteration in the temperature of the uterus. It was recognized that the composition of the fluid in the bladder, always very small in amount, might not have been identical with that of mesonephric urine. Even assuming that the metanephros makes no contribution at the gestation age studied (46 days), changes could have occurred while the fluid remained in the foetal bladders, either before or after the death of the sow. To elucidate the subject further observations were therefore made on surviving pig foetuses with the umbilical vessels intact and in contact with the uterus of the living anaesthetized sow.The objects of this study were two: first, to measure the rate of flow of urine of surviving pig foetuses of two different ages, one before and one after the degeneration of the mesonephros; secondly, to find the composition of such freshly-formed urine. The technique adopted was similar to that of Alexander, Nixon, Widdas & Wohlzogen (1958). It was hoped also that one or other of the three substances (urea, fructose, endogenous creatinine), whose urine: plasma (U: P) ratio was used by Alexander et al. as a measure of water reabsorption in the sheep foetal nephron, would serve the same purpose for the pig foetus, and that in this way an estimation of the glomerular filtration rate could be made. METHODSAnimoal and operation. Pigs (Large White or Large White x Essex) were reared on the laboratory farm of the Department of Experimental Medicine at Bartlow, Cambs., and were served or artificially inseminated there; gilts were used in most cases. The pregnant animal was taken to the A.R.C. Institute of Animal Physiology at Babraham a day or two before

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Section: Resultsmentioning

confidence: 72%

Section: Resultsmentioning

confidence: 99%

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The rate of flow of urine of foetal pigs

Perry¹,

Stanier²

1962

The Journal of Physiology

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The function of the metanephros of foetal rabbits and pigs

McCance¹,

Stanier²

1960

The Journal of Physiology

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The mesonephros of foetal rabbits and pigs does not elaborate a fluid resembling urine (Stanier, 1960), analyses indicating that the fluid found in the bladder when the mesonephros is present resembles a protein-free filtrate of foetal serum. The function of the early definitive kidney (metanephros) has been investigated in a similar way; and since and Widdowson & McCance (1958) suggested that the chorioallantoic membrane may modify the composition of the fluid in the allantoic sac, this fluid has been compared where possible with the metanephric urine. METHODS Animals. Fifteen litters of rabbits at 22 days gestation and eight litters at 27 days gestation were studied (the metanephros is fnnctional by about the 22nd day). Samples of blood from the heart, of fluid from the bladder, and, in the younger litters, of allantoic fluid, were taken from the foetuses as described by Stanier (1960); samples of blood and fluid in the bladder from litter-mates were pooled for analysis.Eleven litters of foetal pigs of 63-67 days gestation and three litters of 90 days gestation were studied. (These ages were chosen because at 67 days the volume of allantoic fluid is about maximal; and at 90 days the allantoic fluid is fast disappearing, so that some individuals of a litter may have none and others may have 200-300 ml.) The uterus was removed within a few minutes of the sow's death, and in most cases samples of the fluids were taken from the foetuses within 60 min of the death of the sow. During this period the uterus was kept warm in an insulated container so that its temperature did not fall below 350 C. The procedure was the same as that described by Stanier (1960) except that samples of bladder fluids from individual foetuses were analysed separately.Chemical estimations. Chloride and urea concentrations were estimated by the procedures already described (Stanier, 1960); total osmolar concentration by the cryoscopic method of Ramsay & Brown (1955); creatinine concentration by the method of Owen, Iggo, Scandrett & Stewart (1954); phosphate on 0-05 ml. samples by the method of Berenblum & Chain (1938); fructose on 0-05 ml. samples by the method of Bacon & Bell (1948). RESULTSThe results from rabbits are shown in Table 1. It was not possible to carry out the whole programme on all three fluids from every litter. The number of figures used for calculating the mean is shown in brackets.

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“…The anatomical relationships and connexions indicate, as has often been suggested, that the sac must act as a receptacle for the fluid secreted by the mesonephros and early metanephros, but the work of Stanier (1960), Crawford & McCance (1960) and McCance & Stanier (1960) indicates that the fluids passing into the sac from the bladder must be greatly modified during their storage there, probably by the chorioallantoic membranes. It still remains to be discovered just how the fluid is created in the early stages of foetal life and how its composition is altered by the active reabsorption of sodium, accompanied by chloride to some extent, and possibly with some simultaneous ionic exchange of sodium for hydrogen and other radicles.…”

Section: Physiological Significance Of the Ph Measurementsmentioning

confidence: 99%