The Placental Transmission of Parathyroid Extract

Hoskins, Felicity; Snyder, Franklin F.

doi:10.1152/ajplegacy.1933.104.3.530

Cited by 30 publications

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“…Increasing foetal plasma protein concentration or foetal parathyroid activity may account for the rise in foetal plasma calcium after 33-39 days. Calcium homeostasis has been much studied in the adult mammal, and there is an extensive literature which agrees that during late foetal life foetal total plasma calcium is greater than that of the mother [Rat: Krukowski and Lehr, 1963;Jost et al, 1963;dog: Hoskins andSnyder, 1927-8 and1933;monkey: MacDonald et al, 1965;cow: Robinson and Huffman, 1926;Plumlee et al, 1952;sheep: Bawden et al, 1965;guinea pig: Burnette et al, 1968;and man: Smith, 1951]. In some cases, differences of as much as 5 mg/100 ml.…”

mentioning

confidence: 99%

Calcium Homeostasis in the Foetal Guinea Pig

Graham

Scothorne

1970

Exp Physiol

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Plasma total calcium levels have been studied in pregnant guinea pigs and their foetuses from 26 days of gestation to term. Between 28 days and 33-39 days the foetal plasma calcium falls from nearly the maternal level (9.6 mg/100 ml.) to 5-5 mg/100 ml. Thereafter the foetal plasma calcium rises, reaching the maternal level at term. No trend is found in the maternal levels. Foetal skeletal ossification was studied using an alizarin stain technique. Ossification centres appeared first in the clavicle, face and skull at 26 days of gestation. After 27 days gestation (foetal plasma protein = 1 g/100 ml.) there is a steady rise in foetal plasma protein level and at term foetal and maternal levels are approximately equal. Between 41 days gestation and term foetal blood is consistently more acid than maternal blood and has a higher pCO2 and lower P02. There is no evidence of a progressive change during gestation in pH, P02 or pCO2 in either foetal or maternal blood. It is concluded that the fall in foetal plasma calcium between 28 days and 33-39 days gestation may be due to calcification of the foetal skeleton before the full establishment of calcium homeostasis in the foetus. Increasing foetal plasma protein concentration or foetal parathyroid activity may account for the rise in foetal plasma calcium after 33-39 days.

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confidence: 99%

Calcium Homeostasis in the Foetal Guinea Pig

Graham

Scothorne

1970

Exp Physiol

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“…Thus, experiments with pregnant rabbits, sheep, guinea pig etc. showed that infusion of Ca-gluconateor chloride, parathyroid hormone, or vitamin D resulted in maternal hypercalcemia, though the fetal blood Ca levels remained unchanged (7, 9,10,11,20,21,22,23,25,33,34).…”

Section: Acta Obster Gynecolmentioning

confidence: 99%

Calcitonin Secretion by Human Placental Tissue

Balabanova

Kruse

Wolf

1987

Acta Obstet Gynecol Scand

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We have investigated the synthesis in vitro of calcitonin (CT) by human placenta at term. Separate placental tissue samples were incubated in culture medium with various Ca concentrations for 6 h. The CT concentrations in the medium were determined by radio-immunoassay. In addition the effect of DB-cAMP on the synthesis was also studied. We could demonstrate CT secretion in all experiments. The CT concentrations were determined by two different antibodies. Both antibodies registered the CT secretion. Addition of DB-cAMP to the culture medium stimulates the synthesis.

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“…The permeability of the placenta for PTH was studied in vivo in several animal experiments [9,11,13,16,18,22,30]. PTH transfer was observed, but the transfer was inconsistent and the amounts of transferred hormone were very small.…”

Section: Introductionmentioning

confidence: 99%

Placental transfer of parathyroid hormone

Balabanova¹,

Lang²,

Wolf³

et al. 1986

Journal of Perinatal Medicine

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We investigated the in vitro transfer of three parathyroid hormone (PTH) fragments (amino acids 35-84, 44-68 and 65-84) through human placenta at term. The perfused and transferred fragments were measured radioimmunologically and identified by three different methods: high-pressure-liquid chromatography (HPLC), preparative flat-bed electrofocusing (PEGG), and gel filtration (GF). The study demonstrated that PTH fragments traverse the human placenta. The transferred and perfused fragments were identical. We observed a significant degradation of the perfused hormone during the passage through the placenta in both fetal and maternal directions. In addition, we measured the PTH concentrations on forty samples of maternal and umbilical cord artery and vein plasma obtained immediately after delivery. A highly significant correlation of PTH concentrations in the maternal and umbilical cord vessels was observed. These findings support the contention that human placenta at term is permeable for PTH fragments.

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The Placental Transmission of Parathyroid Extract

Cited by 30 publications

References 0 publications

Calcium Homeostasis in the Foetal Guinea Pig

Calcium Homeostasis in the Foetal Guinea Pig

Calcitonin Secretion by Human Placental Tissue

Placental transfer of parathyroid hormone

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