Plasma retinol-binding protein (RBP) concentrations have been suggested as surrogate indicators for plasma retinol concentrations in the assessment of vitamin A status in less technologically developed settings. Plasma RBP was measured by radial immunodiffusion and plasma retinol by high performance liquid chromatography in a cross-sectional study of 900 pregnant women at the Queen Elizabeth Central Hospital, Blantyre, Malawi. The Spearman correlation coefficient between plasma RBP and retinol concentrations was 0.95 (p<0.0001). By linear regression, 0.70 micromol l(-1) retinol was equivalent to 21.1 mg l(-1) RBP. With these cut-off points for defining vitamin A deficiency, there was high concordance between categorical descriptions of deficiency using retinol and RBP by chi-square analysis (p<0.001). Measurement of plasma RBP by radial immunodiffusion is simple, inexpensive, and does not require expensive instrumentation. Plasma RBP concentrations measured by radial immunodiffusion are highly correlated with plasma retinol and can be used as a simple surrogate measure for vitamin A concentrations in large field studies.

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Ethylene glycol monomethyl ether (EGME) and its proximate metabolite, 2-methoxyacetic acid (MAA), increase ovarian luteal cell progesterone production in the female rat in vivo and in cultured rat luteal cells in vitro, respectively. In order to better assess the potential hazard of EGME and MAA to women, these studies were conducted to determine whether the same concentrations of MAA increase progesterone in human luteinized granulosa cells as in rat luteal cells. Human cells were collected from healthy anonymous oocyte donors, washed, plated 25,000 viable cells per well, and treated with 10 IU hCG and 0-5 mM MAA for 6-48 hr. Progesterone in media was significantly elevated after 24 hr incubation at 3=1 mM MAA. MAA had no effect on ATP levels at 6 or 24 hr. Thus, MAA increased progesterone production in cultured human luteal cells at the same concentration as MAA increased progesterone in rat luteal cells. The implication is that EGME has the potential to alter ovarian luteal function in women. These data should be useful for determining the real health hazards and potential risks of EGME exposure, e i»7 society of To Ethylene glycol monomethyl ether (EGME) is a commonly used solvent that has been identified as a reproductive toxicant in humans and in animal models of human disease (reviewed in National Institute for Occupational Safety and Health, 1983, 1991). Recently published epidemiological studies have associated ethylene glycol-based solvent exposure in women with increased risks of spontaneous abortion, menstrual cycle dysfunction, and subfertility (Pastides et al., 1988;Gold et al., 1995;Correa et al, 1996). Specifically, solvent-exposed women had a 4.6-fold increase in risk of infertility (95% confidence interval 1.6-13.3) and a 2.8-fold increase in risk of spontaneous abortion (95% confidence interval 1.4-5.6) (Correa et al., 1996). A dose-response relationship between estimated ethylene glycol exposure and each of these outcomes has also been found.Concurrent with the publication of these studies, we determined that the luteal cell is a target for EGME and its proximate toxic metabolite, 2-methoxyacetic acid (MAA), in the female rat (Davis et al., 1997). Specifically, in vivo dosing with EGME (300 mg/kg) elevated serum progesterone and suppressed cyclicity, inhibited ovulation, and increased corpora lutea size by inhibiting luteolysis. In vitro, 1-10 mM MAA elevated progesterone after 24 hr of treatment, but had no effect on cAMP at 1, 3, 24, or 48 hr or ATP levels at 24 hr. Based on these data, we concluded that EGME and MAA increase ovarian luteal cell progesterone production independent of LH-stimulated cAMP.The question remains as to how the reproductive toxicity of EGME and MAA in the rat relates to the potential reproductive toxicity of EGME and MAA in women. To begin to bridge the knowledge gap, this study was designed to determine whether MAA affects progesterone production in cultured human luteinized granulosa cells at concentrations similar to those in the rat and provide data to allow d...