Skip to main content
PMC home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1972 Dec;227(2):503–525. doi: 10.1113/jphysiol.1972.sp010045

Daily changes in foetal urine and relationships with amniotic and allantoic fluid and maternal plasma during the last two months of pregnancy in conscious, unstressed ewes with chronically implanted catheters

D J Mellor, J S Slater
PMCID: PMC1331208  PMID: 4647263

Abstract

1. The fluid sacs and bladders of ten foetuses and the allantoic sacs of five foetuses were catheterized between 79 and 96 days gestational age and daily samples were withdrawn until lambs were born naturally at ∼147 days. Maternal jugular plasma obtained daily allowed the nutritional status of each ewe to be regulated and monitored. All lambs were observed for 7 weeks, and at post-mortem no abnormalities were seen in those operated upon in utero.

2. The osmolality, [Na+], [K+], [Cl-], [glucose], [fructose], [urea], [amino acid] and pH of all samples were measured.

3. Foetal surgery seemed to affect the actual concentrations of some solutes, but gestational trends in foetal fluid composition were unaltered.

4. Until about 7 days before birth the foetal urine osmolality, [Na+], [Cl-] and [fructose] decreased, its [urea], [amino acid] and pH remained relatively constant, and from about 120 days gestational age the [K+] increased. During the last 7 days there was a marked increase in the osmolality and the concentrations of all these solutes, and a decrease in pH.

5. Entry of foetal urine into the fluid sacs tended to decrease the osmolality, [Na+], [K+], [Cl-] and [glucose] of both foetal fluids and the [amino acid] of allantoic fluid, and tended to increase the [fructose] and [urea] of both fluids and the [amino acid] of amniotic fluid.

6. Changes in urine composition suggested large daily variations in the secretion of foetal antidiuretic hormone and also a rapid increase in its secretion during the last 7 days, and particularly the last 2-4 days before birth.

7. Changes in the [Na+]/[K+] ratios of foetal urine and allantoic fluid were parallel during post-operative recovery, during the course of pregnancy and immediately before birth, and this was consistent with a simultaneous action of foetal plasma corticosteroids on the foetal kidneys and chorioallantois.

8. Variations in the [fructose] of foetal urine and allantoic fluid were parallel to changes in their [Na+]/[K+] ratios and suggested an involvement of foetal corticosteroids in the regulation of the [fructose] of foetal plasma.

9. Further evidence has been presented supporting the hypothesis that maternal induced foetal hypoglycaemia effects a relative increase in the secretion of foetal corticosteroids having an action on the chorioallantois. Also, high concentrations of maternal plasma corticosteroids may decrease the permeability of the placenta to glucose.

Full text

PDF
503

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ALEXANDER D. P., NIXON D. A. The foetal kidney. Br Med Bull. 1961 May;17:112–117. doi: 10.1093/oxfordjournals.bmb.a069883. [DOI] [PubMed] [Google Scholar]
  2. ALEXANDER D. P., NIXON D. A., WIDDAS W. F., WOHLZOGEN F. X. Gestational variations in the composition of the foetal fluids and foetal urine in the sheep. J Physiol. 1958 Jan 23;140(1):1–13. doi: 10.1113/jphysiol.1958.sp005911. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. ALEXANDER D. P., NIXON D. A., WIDDAS W. F., WOHLZOGEN F. X. Renal function in the sheep foetus. J Physiol. 1958 Jan 23;140(1):14–22. doi: 10.1113/jphysiol.1958.sp005912. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Alexander D. P., Britton H. G., Forsling M. L., Nixon D. A., Ratcliffe J. G. The concentrations of adrenocorticotrophin, vasopressin and oxytocin in the foetal and maternal plasma of the sheep in the latter half of gestation. J Endocrinol. 1971 Jan;49(1):179–180. doi: 10.1677/joe.0.0490179. [DOI] [PubMed] [Google Scholar]
  5. Bassett J. M., Mills S. C., Reid R. L. The influence of cortisol on glucose utilization in sheep. Metabolism. 1966 Oct;15(10):922–932. doi: 10.1016/0026-0495(66)90163-6. [DOI] [PubMed] [Google Scholar]
  6. Bassett J. M., Oxborrow T. J., Smith I. D., Thorburn G. D. The concentration of progesterone in the peripheral plasma of the pregnant ewe. J Endocrinol. 1969 Nov;45(3):449–457. doi: 10.1677/joe.0.0450449. [DOI] [PubMed] [Google Scholar]
  7. Bassett J. M. The relation of fat and protein catabolic actions of cortisol to glucose homeostasis in fasting sheep. Metabolism. 1968 Jul;17(7):644–652. doi: 10.1016/0026-0495(68)90024-3. [DOI] [PubMed] [Google Scholar]
  8. Bassett J. M., Thorburn G. D. Foetal plasma corticosteroids and the initiation of parturition in sheep. J Endocrinol. 1969 Jun;44(2):285–286. doi: 10.1677/joe.0.0440285. [DOI] [PubMed] [Google Scholar]
  9. Bassett J. M., Thorburn G. D. The regulation of insulin secretion by the ovine foetus in utero. J Endocrinol. 1971 May;50(1):59–74. doi: 10.1677/joe.0.0500059. [DOI] [PubMed] [Google Scholar]
  10. Bassett J. M., Thorburn G. D., Wallace A. L. The plasma growth hormone concentration of the foetal lamb. J Endocrinol. 1970 Oct;48(2):251–263. doi: 10.1677/joe.0.0480251. [DOI] [PubMed] [Google Scholar]
  11. Challis J. R. Sharp increase in free circulating oestrogens immediately before parturition in sheep. Nature. 1971 Jan 15;229(5281):208–208. doi: 10.1038/229208a0. [DOI] [PubMed] [Google Scholar]
  12. Comline R. S., Silver M. Daily changes in foetal and maternal blood of conscious pregnant ewes, with catheters in umbilical and uterine vessels. J Physiol. 1970 Aug;209(3):567–586. doi: 10.1113/jphysiol.1970.sp009180. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Comline R. S., Silver M. The composition of foetal and maternal blood during parturition in the ewe. J Physiol. 1972 Apr;222(1):233–256. doi: 10.1113/jphysiol.1972.sp009795. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. JONES I. C., JARRETT I. G., VINSON G. P., POTTER K. ADRENOCORTICOSTEROID PRODUCTION OF FOETAL SHEEP NEAR TERM. J Endocrinol. 1964 May;29:211–212. doi: 10.1677/joe.0.0290211. [DOI] [PubMed] [Google Scholar]
  15. Liggins G. C. Premature delivery of foetal lambs infused with glucocorticoids. J Endocrinol. 1969 Dec;45(4):515–523. doi: 10.1677/joe.0.0450515. [DOI] [PubMed] [Google Scholar]
  16. Liggins G. C. Premature parturition after infusion of corticotrophin or cortisol into foetal lambs. J Endocrinol. 1968 Oct;42(2):323–329. doi: 10.1677/joe.0.0420323. [DOI] [PubMed] [Google Scholar]
  17. MESCHIA G., COTTER J. R., BREATHNACH C. S., BARRON D. H. THE HEMOGLOBIN, OXYGEN, CARBON DIOXIDE AND HYDROGEN ION CONCENTRATIONS IN THE UMBILICAL BLOODS OF SHEEP AND GOATS AS SAMPLED VIA INDWELLING PLASTIC CATHETERS. Q J Exp Physiol Cogn Med Sci. 1965 Apr;50:185–195. doi: 10.1113/expphysiol.1965.sp001780. [DOI] [PubMed] [Google Scholar]
  18. Mellor D. J. A technique for chronic catheterization of the amniotic and allantoic sacs of sheep foetuses. Res Vet Sci. 1970 Jan;11(1):93–95. [PubMed] [Google Scholar]
  19. Mellor D. J. Distribution of ions and electrical potential differences between mother and foetus at different gestational ages in goats and sheep. J Physiol. 1970 Mar;207(1):133–150. doi: 10.1113/jphysiol.1970.sp009053. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Mellor D. J., Slater J. S., Cockburn F. Effects of antibiotic treatment on the composition of sheep foetal fluids. Res Vet Sci. 1971 Nov;12(6):521–526. [PubMed] [Google Scholar]
  21. Mellor D. J., Slater J. S. Daily changes in amniotic and allantoic fluid during the last three months of pregnancy in conscious, unstressed ewes, with catheters in their foetal fluid sacs. J Physiol. 1971 Sep;217(3):573–604. doi: 10.1113/jphysiol.1971.sp009587. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Mellor D. J., Slater J. S. Preparturient changes in the pH of urine from chronically catheterized foetal sheep. Res Vet Sci. 1972 Jan;13(1):89–90. [PubMed] [Google Scholar]
  23. Mellor D. J. Vascular anastomosis and fusion of foetal membranes in multiple pregnancy in the sheep. Res Vet Sci. 1969 Jul;10(4):361–367. [PubMed] [Google Scholar]
  24. Mellor D. J., Williams J. T., Matheson I. C. A technique for chronic catheterization of the bladder of the foetal sheep. Res Vet Sci. 1972 Jan;13(1):87–88. [PubMed] [Google Scholar]
  25. Reid R. L. The physiopathology of undernourishment in pregnant sheep, with particular reference to pregnancy toxemia. Adv Vet Sci. 1968;12:163–238. [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES