Evolution of Phosphatemia in the Rat Fetus during the Late Stages of Gestation

Garel, Jean‐Michel; P, Pic

doi:10.1159/000240525

Cited by 9 publications

(5 citation statements)

References 2 publications

(2 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At term the mammalian fetus has been reported to be hypercalcemic (1-4) and hyperphosphatemic (5-7), conditions which developed over a period of time in the final stages of gestation (10)(11)(12)(13). The present report confirms the gradual buildup of calcium and phosphorus in fetal blood and demonstrates, in addition, that as circulating levels of these elements rise, blood pH falls.…”

Section: Administration Of Ammonium Chloride or Sodium Bicarbonate Tosupporting

confidence: 74%

See 1 more Smart Citation

Acidosis, Hypercalcemia, and Hyperphosphatemia in Rat Fetuses near Term and Effects of Maternal Acid/Base Loading

Krukowski

Smith

1979

Experimental Biology and Medicine

View full text Add to dashboard Cite

In most mammalian species examined, the levels of calcium (1-4) and of phosphorus (5-7) in the blood of the fetus at term exceed those of the dam. The difference in serum calcium between mother and fetus may, in part, be explained by the observation that the circulating level of this element in the dam falls in the final stages of gestation (5,8,9). In addition, in the many mammals investigated, the level of calcium in the blood of the fetus has been shown to increase as termination of pregnancy is approached (10-12). Finally, in the rat, fetal phosphatemia has been shown to parallel the rise in blood calcium in the last days before birth (13).We have previously demonstrated that rat fetuses are acidotic near term, and that in utero hypercalcemia and early neonatal hypocalcemia are associated with low blood pH and normalization of blood pH, respectively (14). In view of this apparent association at term and immediately after birth, the present studies were undertaken: (i) to investigate whether in the final stages of gestation fetal blood pH shifts concurrently with reported alterations in the levels of calcium and phosphorus; and (ii) to test the hypothesis that changes in the circulating levels of calcium and phosphorus are causally related to blood pH in the developing mammal in utero, by either aggravating or alleviating the acidotic state of the conceptus by the maternal administration of ammonium chloride or sodium bicarbonate, respectively.Materials and methods. Four-to eightmonth-old pregnant albino rats and their offspring were used. The adult animals were maintained on Purina laboratory chow and tap water ad libitum and housed in a temperature-controlled room illuminated on a 14hr-light/ 10-hr-dark cycle.In order to obtain females at a known time Work supported by National Institutes of Health Grant HD 07419-3.of gestation, the animals were caged with males for a single overnight period. The day of mating was counted as Day 0, and experiments were terminated at preselected times during the last week of pregnancy. Studies on fetuses in the final week of gestation.Beginning on Day 17 and then daily through the 22nd day of pregnancy, groups of animals were handled as follows:The gravid female was lightly anesthetized with ether, a laparotomy was performed, and the pregnant uterus was exposed. Fetuses were sequentially bled and excised until the entire litter was sampled. Fetal blood was taken from the axilla while the placental and umbilical circulations were intact. Tail blood was drawn from the mother at the beginning and end of each experiment.Studies on offspring of pregnant animals receiving either ammoniunt chloride or sodium bicarbonate orally. Pregnant animals were divided into three groups. Beginning on the 17th day of gestation, tap water was removed and the following substitutions were made. One group of animals was given a solution of 1.5% NH4Cl, the second group received a 1.5% solution of NaHC03, and the remaining rats were given distilled water. Animals were allowed to drink freely and fluid...

show abstract

Section: Administration Of Ammonium Chloride or Sodium Bicarbonate Tosupporting

confidence: 74%

“…In addition, in the many mammals investigated, the level of calcium in the blood of the fetus has been shown to increase as termination of pregnancy is approached (10)(11)(12). Finally, in the rat, fetal phosphatemia has been shown to parallel the rise in blood calcium in the last days before birth (13).…”

mentioning

confidence: 99%

Acidosis, Hypercalcemia, and Hyperphosphatemia in Rat Fetuses near Term and Effects of Maternal Acid/Base Loading

Krukowski

Smith

1979

Experimental Biology and Medicine

View full text Add to dashboard Cite

show abstract

“…Consequently, serum phosphorus is an important determinant of the formation and mineralization of bone during fetal development. It is typically 0.5-1.0 mM higher in the fetus than in the mother, as observed in rats (211,213,315,346), mice (623), lambs (377,403,435), pigs (98,353), calves (201), and foals (201). Fetuses maintained normal phosphorus levels despite hypophosphatemia in pregnant rats and mice (207,395).…”

Section: Animal Datamentioning

confidence: 90%

Bone Development and Mineral Homeostasis in the Fetus and Neonate: Roles of the Calciotropic and Phosphotropic Hormones

Kovacs

2014

Physiological Reviews

208

188

View full text Add to dashboard Cite

Mineral and bone metabolism are regulated differently in utero compared with the adult. The fetal kidneys, intestines, and skeleton are not dominant sources of mineral supply for the fetus. Instead, the placenta meets the fetal need for mineral by actively transporting calcium, phosphorus, and magnesium from the maternal circulation. These minerals are maintained in the fetal circulation at higher concentrations than in the mother and normal adult, and such high levels appear necessary for the developing skeleton to accrete a normal amount of mineral by term. Parathyroid hormone (PTH) and calcitriol circulate at low concentrations in the fetal circulation. Fetal bone development and the regulation of serum minerals are critically dependent on PTH and PTH-related protein, but not vitamin D/calcitriol, fibroblast growth factor-23, calcitonin, or the sex steroids. After birth, the serum calcium falls and phosphorus rises before gradually reaching adult values over the subsequent 24 -48 h. The intestines are the main source of mineral for the neonate, while the kidneys reabsorb mineral, and bone turnover contributes mineral to the circulation. This switch in the regulation of mineral homeostasis is triggered by loss of the placenta and a postnatal fall in serum calcium, and is followed in sequence by a rise in PTH and then an increase in calcitriol. Intestinal calcium absorption is initially a passive process facilitated by lactose, but later becomes active and calcitriol-dependent. However, calcitriol's role can be bypassed by increasing the calcium content of the diet, or by parenteral administration of calcium.

show abstract

“…This increase in the magnesium balance may be due to higher maternal requirements during this final period of gestation in order to meet fetal demands , caused by the beginning of ossification and rapid fetal growth (7,18,20).…”

Section: Discussionmentioning

confidence: 99%

Magnesium utilization during gestation in the rat and effect of hydrocortisone on it.

Aranda

López-Jurado

Llopis

et al. 1986

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

View full text Add to dashboard Cite

SummaryThe changes of magnesium utilization during pregnancy in rat and the influence of hydrocortisone acetate on it was studied. In the late days of gestation the Mg balance and magnesium content of bone increased significantly. This may be due to a greater requirement at this stage and to bone acting as a store for this cation. Hydrocortisone acetate at a dose of 4 mg/100g body weight/day decreased the magnesium balance but did not modify the bone content of this mineral. The hormone had a catabolic effect on Longissimus dorsi muscle, producing a loss in mag nesium. The effect is directly proportional to the duration of treatment.

show abstract

Evolution of Phosphatemia in the Rat Fetus during the Late Stages of Gestation

Cited by 9 publications

References 2 publications

Acidosis, Hypercalcemia, and Hyperphosphatemia in Rat Fetuses near Term and Effects of Maternal Acid/Base Loading

Acidosis, Hypercalcemia, and Hyperphosphatemia in Rat Fetuses near Term and Effects of Maternal Acid/Base Loading

Bone Development and Mineral Homeostasis in the Fetus and Neonate: Roles of the Calciotropic and Phosphotropic Hormones

Magnesium utilization during gestation in the rat and effect of hydrocortisone on it.

Contact Info

Product

Resources

About