Biochemical differentiation of gestational compartments in the midgestational fetal rabbit

Objectives: The fetal rabbit at midgestation is increasingly being used as a model in fetal diagnosis and therapy. In this study, we aimed to establis h a reliable method for identification of the origin of sampled extra-embry onic fluids based on selected biochemical components. Methods: In 6 pregnan t does at 22 days of gestation, 18 gestational sacs were sampled for amniot ic, allantoic and exocoelomic fluid. These fluids, as well as matching mate rnal and fetal blood samples, were assayed for levels of sodium, potassium, chloride, bicarbonate, total protein, alkaline phosphatase, gamma -glutamy l transferase and progesterone. Results: Levels of sodium and potassium wer e, respectively, lower and higher in the allantoic fluid when compared to o ther extra-embryonic spaces. Amniotic fluid had a significantly lower total protein content and higher level of alkaline phosphatase when compared to the exocoelomic fluid. Significant levels of progesterone could only be det ected in maternal blood. Conclusions: In the midgestational rabbit, a combi ned assay of potassium, alkaline phosphatase and progesterone can determine the gestational cavity of origin of the sampled fluid. The obtained gradie nts for these markers suggest compartment-specific production and/or interc avity transfer mechanisms. Copyright (C) 2001 S. Karger AG, Basel.