Early safety of tenofovir alafenamide in patients with a history of tubulopathy on tenofovir disoproxil fumarate: a randomized controlled clinical trial.

OBJECTIVES: The aim of the study was to assess the effect of tenofovir alafenamide (TAF) on kidney and bone biomarkers in patients who developed proximal renal tubulopathy (PRT) while receiving tenofovir disoproxil fumarate (TDF). METHODS: Individuals with a history of TDF-associated PRT and currently suppressed HIV infection on a tenofovir-sparing regimen were randomized 1:1 to continue current antiretroviral therapy or initiate emtricitabine (F)/TAF with discontinuation of nucleoside reverse transcriptase inhibitors (NRTIs) as appropriate. Renal and bone biomarkers were analysed at baseline, week 4 and week 12. The primary outcome was the mean difference between study arms in urine retinol-binding protein:creatinine ratio (RBPCR) change from baseline to week 12. Data were analysed using linear regression, with robust standard errors (primary outcome), and repeated measures mixed effects models (secondary outcomes). The trial was registered under European Union Drug Regulating Authorities Clinical Trials Database 2016-003345-29. RESULTS: We randomized 31 individuals [mean age 52.4 (standard deviation 0.3) years; 97% male; 90% white); all completed the study. At 12 weeks, there was no difference in change in RBPCR (ß 19.6; 95% confidence interval -35.3, 74.5; P = 0.47), and no difference in change in estimated glomerular filtration rate (eGFR) (based on creatinine or cystatin C), albuminuria, proteinuria, renal phosphate or urea handling, (fasting) urine osmolality, parathyroid hormone and bone turnover markers in the control versus the F/TAF exposed groups. No cases of PRT were observed. CONCLUSIONS: In people with a history of proximal renal tubulopathy while on TDF, 12-week exposure to TAF did not adversely affect renal tubular function. These data support continued evaluation of the long-term safety of TAF in this group of patients.

[Changes in serum ß2-microglobulin, retinol-binding protein, and cystatin C and their value in identifying early renal dysfunction in patients with chronic hepatitis B undergoing tenofovir or entecavir monotherapy: a comparative analysis].

Objective: To investigate the dynamic changes in serum ß2-microglobulin, retinol-binding protein, and cystatin C in chronic hepatitis B(CHB)patients treated with tenofovir or entecavir alone as the anti-HBV therapy, as well as their value in identifying early renal dysfunction. Methods: A total of 61 previously untreated CHB patients who were diagnosed and treated in the Department of Infectious Diseases in Henan Provincial People's Hospital from June 2013 to August 2015 were enrolled and divided into tenofovir group and entecavir group. The serum levels of ß2-microglobulin, retinol-binding protein, cystatin C, and creatinine and estimated glomerular filtration rate(eGFR)were compared between the two groups at baseline and 4, 8, 39, 52, 78, and 104 weeks after antiviral therapy. The independent samples t-test was used for comparison of continuous data, and the chi-square test was used for comparison of categorical data. P < 0.05 was considered statistically significant. Results: A total of 61 CHB patients were enrolled, with 31 in the tenofovir group and 30 in the entecavir group. The two groups had comparable serum levels of ß2-microglobulin, retinol-binding protein, and cystatin C at baseline, but there were significant differences in ß2-microglobulin and retinol-binding protein over time(both P < 0.05). There was a significant difference in cystatin C at 78 weeks(t = -2.062, P = 0.044), but there was no significant difference at 104 weeks(t = -1.544, P = 0.128). There were no significant differences in serum creatinine or eGFR at any time point between the two groups(P > 0.05). At 104 weeks, there were no significant differences in HBV-DNA clearance rate or the level of virologic breakthrough between the two groups(P > 0.05). Conclusion: Serum ß2-microglobulin, retinol binding protein, and cystatin C are more sensitive than eGFR in the monitoring of early renal dysfunction during the anti-HBV therapy with tenofovir or entecavir alone.

[Effect of zhuhong ointment on renal antioxidant capability in skin ulcer model rats].

OBJECTIVE: To study the effect of repeated administration of Zhuhong ointment on renal antioxidant capability of ulcerous skin in rats, in order to further discuss the mechanism of mercury contained in Zhuhong ointment on the antioxidant capability of kidney in skin ulcer rats. METHOD: Eighty SD rats were randomly divided into eight groups: Zhuhong ointment A, B, C, D, E (1.219, 0.609, 0.305, 0.152, 0.76 g x kg(-1)) groups, the vaseline group, the ulcer model group and the impairment control group. The levels of NAG and RBP of toxicity for early kidney tubular injury and T-AOC, SOD, GSH-PX and GSH in kidney were determined after consecutive administration for 14 days. RESULT: Compared with ulcer model group, the levels of RBP in groups A, B, C and D increased, while the levels of NAG increased only in the group A. The level of T-AOC increased in groups A, B and C. The level of T-SOD increased in the group E, while it dropped down greatly in the group A. The level of GSH-PX increased in groups A, B and C. The content of GSH increased in every dose groups. CONCLUSION: Antioxidant capacity in rats can be increased in a reasonable dose of Zhuhong ointment, but some antioxidant activity can be notably inhibited by with the increase of dose.

[Effects of zhuhong ointment on mercury cumulation and renal organization modality in skin-impaired model rat].

OBJECTIVE: To study the effects of Zhuhong ointment on accumulation in the body of mercury and the pathological morphology changes of kidney, via the measurement of related indicators of the skin-impaired model rat. METHOD: Eighty-eight SD rats were randomly divided into the impairment control group, and high-, middle-, low-dose Zhuhong ointment groups. Each group was treated by corresponding methods for 4 weeks, and recovering for 4 weeks. Urinary potein (PRO), pH, Beta N-acetyl aminoglycosidase enzymes (NAG) and beta2-microglobulin (beta2-MG) contents in urine were taken as monitoring indexes, blood urea nitrogen (BUN) and serum creatinine (SCr) in blood and the levels of mercury in urine, blood and kidney were tested, and the pathological morphology changes of kidney were observed. RESULT: After treatment for 4 weeks, compared with impairment control group, the levels of mercury in urine, blood and kidney in every dose group increased significantly (P < 0.01). And the relation exists between toxicity and dose on Zhuhong ointment. After recovery for 4 weeks, the levels of mercury in urine and blood in every dose group restore normal, while the level of mercury in kidney in high- dose group still increased (P < 0.01). The level of NAG increased only in high-dose group. There was no significant difference in NAG contents between Zhuhong ointment groups and the impairment control group (P < 0.05). CONCLUSION: Excess using Zhuhong ointment repeatedly may lead to accumulation of mercury and pathological morphology changes of kidney. So the levels of mercury in the body and related indicators of renal functions should be tested in clinical when long-term using Zhuhong ointment.

Solvent-induced ligand dissociation and conformational states of Cellular Retinol-Binding Protein type I.

Cellular Retinol-Binding Protein type I (CRBP) exhibits very high affinity for its ligand, bound within a buried cavity completely shielded from the outside medium. Three-dimensional structure and backbone dynamics in aqueous solution at neutral pH, either in the absence or in the presence of retinol, fail to represent the protein in a state capable of ligand uptake and release. The question was asked whether changes in the composition of the outside medium might facilitate ligand dissociation. Acidic aqueous solutions and water-alcohol mixtures were selected, among the best described denaturing solvents, to investigate their effects on the stability of the carrier-ligand complex and the conformational state of the protein upon ligand release. Circular dichroism (CD) and fluorescence spectroscopy were used to probe protein secondary and tertiary structure, compactness and retinol dissociation. While in purely aqueous media retinol dissociation parallels the acid-induced denaturation of the carrier, in water-alcohol mixtures it occurs in a range of co-solvent content lower than that required for protein denaturation. In light of these results, it is suggested that local solvent properties in vivo might modulate protein conformation and flexibility and thus play a fundamental role in the control of retinol exchange between carrier and membrane-bound donors and acceptors.

Human choriocarcinoma cell line JEG-3 produces and secretes active retinoids from retinol.

Vitamin A (retinol) and its active derivatives (the retinoids) are essential for growth and development of the mammalian fetus. Maternally-derived retinol has to pass through the placenta to reach the developing fetus. Despite its apparent importance, little is known about placental metabolism of retinol, and particularly placental production and/or secretion of active retinoids. It has been previously considered that retinoids are recruited from the uterine environment to influence placental development and function during gestation. We have studied retinoid metabolism in the human choriocarcinoma cell line JEG-3 and demonstrate, for the first time, that active retinoids are produced endogenously by the JEG-3 cell line from retinol. These retinoids induce gene expression from a retinoic acid-responsive enhancer element reporter plasmid and modulate placental transglutaminase activity. Furthermore, retinoids are secreted from JEG-3, as shown by the activation of retinoic acid-responsive beta lacZ reporter cells grown in conditioned media. These results suggest that there could be an active role for trophoblast-derived retinoids during human development.

The effect of retinoids and butyrate on the expression of CRX and IRBP in retinoblastoma cells.

We sought to determine whether differentiation agents such as retinoids and butyrate regulate transcript levels of interphotoreceptor retinoid binding protein (IRBP) and cone rod homeobox (CRX), a homeodomain transcription factor that regulates IRBP promoter activity. WERI-Rb1 retinoblastoma cells were treated with all-trans retinol, all-trans retinoic acid, or butyrate. IRBP and CRX mRNA levels were determined by quantitative RT-PCR. Butyrate at low concentrations increased both mRNA levels but suppressed them at higher concentrations. Retinoic acid had minimal effects. Retinol increased CRX mRNA over four fold. IRBP and CRX transcript levels are sensitive to butyrate and CRX expression is sensitive to retinol.

Endogenous CRX expression and IRBP promoter activity in retinoblastoma cells.

PURPOSE: To determine whether antisense oligonucleotides (AODNs) targeted against CRX, a photoreceptor-specific trans-acting factor, suppress CRX expression and interphotoreceptor retinoid binding protein (IRBP) promoter activity. METHODS: Cultures of human retinoblastoma cells were transfected with chloramphenicol acetyltransferase (CAT) reporter plasmids containing a mouse IRBP promoter and AODNs directed against CRX. RT-PCR using primers specific to CRX, OTX2, GAPDH, or RNase H was conducted on total RNA isolated from retinoblastoma cells at various times following transfection with AODNs. RESULTS: Transfection of retinoblastoma cells with IRBP promoter CAT constructs alone produced high activity. Co-transfection with AODNs suppressed IRBP promoter activity in a concentration-dependent manner, with half-maximal effect produced at about 2 nM AODN concentration. Transfection with CAT constructs containing an SV40 promoter produced high activity that was unaffected by co-transfection with AODNs. RT-PCR products were obtained for all target sequences. CRX RT-PCR product from cells transfected with AODNs was greatly diminished following transfection with an AODN whereas control transcripts, including that of OTX2, were relatively unaffected. CONCLUSIONS: The CRX-specific AODNs specifically and potently suppressed CRX expression and IRBP promoter activity, as measured by RT-PCR and transient transfection assays, respectively. Little or no effect was seen on controls. These data suggest that endogenous CRX is required for IRBP promoter activity in retinoblastoma cells.

Transthyretin, thyroxine, and retinol-binding protein in human cerebrospinal fluid: effect of lead exposure.

Transthyretin (TTR), synthesized by the choroid plexus, is proposed to have a role in transport of thyroid hormones in the brain. Our previous studies in animals suggest that sequestration of lead (Pb) in the choroid plexus may lead to a marked decrease in TTR levels in the cerebrospinal fluid (CSF). The objectives of this study were to establish in humans whether TTR and thyroxine (T(4)) are correlated in the CSF, and whether CSF levels of Pb are associated with those of TTR, T(4), and/or retinol-binding protein (RBP). Eighty-two paired CSF and blood/serum samples were collected from patients undergoing clinical diagnosis of CSF chemistry. Results showed that the mean value of CSF concentrations for TTR was 3.33 +/- 1.60 microg/mg of CSF proteins (mean +/- SD, n = 82), for total T(4) (TT(4)) was 1.56 +/- 1.68 ng/mg (n = 82), for RBP was 0.34 +/- 0.19 microg/mg (n = 82), and for Pb was 0.53 +/- 0.69 microg/dl (n = 61 for those above the detection limit). Linear regression analyses revealed that CSF TTR levels were positively associated with those of CSF TT(4) (r = 0.33, p < 0.005). CSF TTR concentrations, however, were inversely associated with CSF Pb concentrations (r = -0.29, p < 0.05). There was an inverse, albeit weak, correlation between CSF TT(4) and CSF Pb concentrations (r = -0.22, p = 0.09). The concentrations of TTR, TT(4), and Pb in the CSF did not vary as the function of their levels in blood or serum, but RBP concentrations in the CSF did correlate to those of serum (r = 0.39, p < 0.0005). Unlike TTR, CSF RBP concentrations were not influenced by PB: These human data are consistent with our earlier observations in animals, which suggest that TTR is required for thyroxine transport in the CSF and that Pb exposure is likely associated with diminished TTR levels in the CSF.

Interaction between inflammatory cells and heparin-surface-modified intraocular lens.

PURPOSE: To investigate the interaction and adherence of inflammatory cells to a heparin-surface-modified intraocular lens (HSM IOL). SETTING: Department of Ophthalmology, Tokyo Medical University Hospital, Tokyo, Japan. METHODS: Splenic mononuclear leukocytes from rats with experimental autoimmune uveitis were cultured with the optic of an HSM IOL for 96 hours. The number of adherent cells on the HSM IOL surface was measured with and without the addition of interphotoreceptor retinoid-binding protein and concanavalin A (ConA) to the culture medium. The adherent cells were observed under a light microscope or a scanning electron microscope. RESULTS: Interphotoreceptor retinoid-binding protein and ConA increased the number of adherent cells on the HSM IOL relative to the control. Adherent cells on the HSM IOL were small and round, considered to be mainly lymphocytes. CONCLUSION: Activated lymphocytes tended to adhere to the surface of the HSM IOL.

Occupational exposure to tetrachloroethene and its effects on the kidneys.

Occupational exposure to tetrachloroethene (TCE) has been reported to cause early adverse effects on the kidneys. We investigated the effects of TCE exposure on the kidneys in 82 exposed and 19 nonexposed workers from four dry-cleaning shops in The Netherlands. The mean inhaled amount of TCE in the exposed group, which was assessed by determination of its concentration in alveolar air samples, was 8.4 mg/m3 (range, 2.2-44.6 mg/m3). This value corresponds to a mean 8-hour time-weighted average exposure of 7.9 mg/m3 (range, 1-221 mg/m3). A chronic dose index (CDI) was estimated from data on the current TCE dose and the occupational history of the individual subjects. The mean CDI in the exposed group was 400 months X mg/m3 (range, 12-4882 months X mg/m3). Effects on the tubules were assessed with the parameters N-acetyl-beta-D-glucosaminidase, beta-galactosidase, alanine aminopeptidase, and retinol-binding protein (RBP) in urine. Early effects on the glomeruli were monitored with the parameter albumin in urine. Total protein in urine was determined for the general assessment of effects on the glomeruli and tubules. The tubular parameter RBP was increased in the exposed group, compared with the nonexposed group. None of the other parameters differed between the study groups, and none of the renal-effect parameters correlated with the TCE dose or the CDI. In conclusion, occupational exposure to TCE may cause a minor effect on the tubular RBP at exposure levels below the Dutch occupational exposure limit (240 mg/m3).

Induction of mouse retinol binding protein gene expression by cyclic AMP in Hepa 1-6 cells.

Retinol binding protein (RBP) is the primary circulating transport molecule for retinol, facilitating its transport to target tissues and influencing target cell uptake. Specific signals and molecular mechanisms that regulate RBP gene expression are poorly understood. Using the mouse hepatoma cell line (Hepa 1-6), we examined the role of cAMP in the molecular regulation of RBP. Dibutyryl cAMP (dbcAMP) or the adenylate cyclase activator, forskolin, increased RBP mRNA levels >6-fold at 24 h. Increases in RBP mRNA were dose dependent over the range of 10 microM-1 mM for dbcAMP and 0.5-10 microM for forskolin. 8-Bromo cAMP, a nonhydrolyzable analog, over the range of 0.01-0.5 mM, increased RBP mRNA levels 9.2-fold at 24 h. Induction of RBP transcripts by analogs also resulted in a comparable increase in intracellular RBP protein. Cycloheximide (10 microgram/ml) did not prevent cAMP-mediated induction of RBP mRNA, indicating that de novo protein synthesis is not required for cAMP-mediated induction of RBP transcription. These studies demonstrate that cAMP, or agents which elevate intracellular cAMP, increase RBP transcript levels. The time course and extent of RBP mRNA induction and the resultant increase in RBP protein support the concept that cAMP regulation of RBP gene expression may be physiologically relevent. Given the ubiquitous nature of cAMP as a second messenger, and the several mechanisms by which cAMP regulates gene expression, studies are in progress to define molecular mechanisms by which cAMP regulates RBP gene expression.

Retinoic acid increases cellular retinol binding protein II mRNA and retinol uptake in the human intestinal Caco-2 cell line.

Cellular retinol binding protein II (CRBPII) is an abundant small intestinal protein that facilitates vitamin A trafficking and metabolism. The magnitude of retinol uptake and metabolism correlate to CRBPII levels in the human intestinal Caco-2 cell line. To investigate the importance of retinoic acid receptor response elements in the promoter of the CRBPII gene, retinoic acid regulation of CRBPII expression and vitamin A absorption was studied in differentiated Caco-2 cells. All-trans- or 9-cis-retinoic acid increased CRBPII mRNA levels two- to threefold. This was associated with a 50% increase in retinol absorption. Retinoic acid receptor beta and apolipoprotein A1 regulatory protein-1, two nuclear receptors that bind to the CRBPII promoter, were also induced, whereas other retinoid and orphan receptors were not. Thus, retinoic acid may regulate CRBPII expression directly or by selectively changing levels of nuclear receptors or other factors. These studies are the first to demonstrate that retinoic acid can modulate endogenous CRBPII mRNA levels and retinol absorption in Caco-2 cells and suggest that human intestinal vitamin A absorption may be regulated by retinoids.

Induction of the oxidative catabolism of retinoid acid in MCF-7 cells.

Cytochrome P450-dependent oxidation is a pathway for all-trans-retinoic acid (all-trans-RA) catabolism. Induction of this catabolic pathway was studied in MCF-7 breast cancer cells. MCF-7 cells showed low constitutive all-trans-RA catabolism. Concentration-dependent induction was obtained by preincubation of the cells with all-trans-RA (10(-9) to 10(-6) M). Onset of induction was fast, being detectable within 60 min, with maximal induction (45-fold) obtained after 16 h. Enzymatic characterization of induced all-trans-RA catabolism showed an estimated Km value (Michaelis-Menten constant) of 0.33 microM and a Vmax value (maximal velocity of an enzyme-catalysed reaction) of 54.5 fmol polar all-trans-RA metabolites 10(6) cells(-1) h(-1). These kinetic parameters represent the overall formation of polar metabolites from all-trans-RA. Induction of all-trans-RA catabolism was also obtained with other retinoids, CH55 >> 13-cis-RA = all-trans-RA > 9-cis-RA > 4-keto-all-trans-RA > 4-keto-13-cis-RA > retinol. The potency of the retinoids to induce all-trans-RA catabolism was correlated to their retinoic acid receptor affinity (Crettaz et al, 1990; Repa et al, 1990; Sani et al, 1990). Induction of all-trans-RA catabolism was inhibited by actinomycin D. Furthermore, all-trans-RA did not increase cytosolic retinoic acid-binding protein (CRABP) mRNA levels. These data suggest that induction of all-trans-RA catabolism in MCF-7 cells is a retinoic acid receptor-mediated gene transcriptional event. Induced all-trans-RA catabolism was inhibited by various retinoids with decreasing potency in the order: all-trans-RA > 4-keto-all-trans-RA > 13-cis-RA > 9-cis-RA > 4-keto-13-cis-RA > retinol > CH55. The antitumoral compound liarozole-fumarate inhibited all-trans-RA catabolism with a potency similar to that of all-trans-RA.

Retinyl methyl ether: binding to transport proteins and effect on transcriptional regulation.

Retinyl methyl ether (RME) which prevents cancers of the rat mammary gland, binds to cellular retinol-binding protein and serum retinol-binding protein but not to cellular retinoic acid-binding protein or to the nuclear retinoid receptors, RARs/RXRs. Since the biochemical effects of retinoids likely involve activation or suppression of RAR/RXR-mediated gene transcription, we evaluated such activity of RME by performing cotransfection assays involving CV-1 cells, expression vectors containing RAR and/or RXR cDNA, and an appropriate reporter vector. In the concentration range of 10(-9)-10(-6), RME did not activate transcription by either of the heterodimers (RARalpha, beta or gamma/RXR alpha) or the homodimer (RARalpha/RARalpha). The retinoid, however, exhibited concentration-dependent inhibitory effects on the basal level of transcriptional activity (no other retinoid added) of both the RAR beta- and RARgamma/RXRalpha heterodimers and of the retinoic acid-induced transcriptional activation of the RARgamma/RXRalpha receptors. Thus, RME acted as a retinoic acid antagonist, a role possibly involved in its cancer preventive activity.

Unsaturated fatty acids regulate gene expression of cellular retinol-binding protein, type II in rat jejunum.

We have shown that cellular retinol-binding protein, type II (CRBP II) mRNA and its protein levels are elevated in the jejunum of rats fed a diet rich in long-chain triacylglycerols. In the present study, we explored which types of fatty acids modulate CRBP II gene expression. Rats previously fed a low fat, high starch diet were force-fed a basal fat-free diet or the diet supplemented with 0.21 mol/L of various fatty acids (i.e., caprylic, palmitic, stearic, oleic, linoleic and alpha-linolenic acids). Force-feeding a diet containing linoleic acid produced an elevation of CRBP II mRNA levels in rats in both a dose-dependent (0.053-0.21 mol/L) and time-dependent (up to 6 h) manner. Among fatty acids tested, all unsaturated fatty acids (oleic, linoleic and alpha-linolenic acids) were able to enhance CRBP II mRNA levels by 54-63% within 6 h, whereas a medium-chain fatty acid (caprylic acid) and a saturated fatty acid (stearic acid) elicited little effect on the CRBP II mRNA levels; palmitic acid produced only a small elevation (16%) of the CRBP II mRNA level. Transcripts of both retinoid X receptor alpha and peroxisome proliferator-activated receptor (PPAR), which are thought to interact as a heterodimer with the cis-element located in the CRBP II promoter and to be activated by 9-cis retinoic acid and long-chain fatty acids, respectively, were constitutively expressed in the rat jejunum.(ABSTRACT TRUNCATED AT 250 WORDS)

Consumption of excess vitamin A, but not excess beta-carotene, causes accumulation of retinol that exceeds the binding capacity of cellular retinol-binding protein, type II in rat intestine.

We assessed the effects of excess dietary vitamin A or beta-carotene on the cellular retinol-binding protein, type II [CRBP(II)] level and activities of lecithin: retinol acyltransferase (LRAT) and acyl-CoA:retinol acyltransferase (ARAT) in rat intestine. Male rats were fed for 7 d diets containing amounts of retinyl acetate or beta-carotene that were 1 (control), 10, 100 and 1000 times the NRC recommended requirement. No responses of the jejunal CRBP(II) level to an intake of excess vitamin A or beta-carotene were observed. The unesterified retinol and retinyl palmitate concentrations in the jejunum were small in rats fed 10 times the vitamin A requirement but they were significantly greater in rats fed 100 and 1000 times the vitamin A requirement than in controls. The molar ratio of unesterified retinol/CRBP(II) was < 1 for the controls and the group fed 10 times the vitamin A requirement, but > 3 for the group fed 100 times the requirement and > 19 for the group fed 1000 times the requirement. The LRAT activity was significantly greater in rats fed 1000 times the vitamin A requirement compared with all other groups, but ARAT activity was unaffected. Consumption of excess beta-carotene did not alter LRAT or ARAT activity, and led to a very small deposition of unesterified retinol and retinyl palmitate in the jejunum. Because CRBP(II) may play an important role in preventing the toxic effect of unbound retinol in the small intestine, consumption of excess vitamin A in amounts < 10 times the NRC recommended requirement may not cause a disturbance of the absorptive cell function.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of antenatal betamethasone on cord blood concentrations of retinol-binding protein, transthyretin, transferrin, retinol, and vitamin E.

We assessed the effect of short-term (less than or equal to 1 week) and prolonged (greater than 1 week) exposure to antenatal betamethasone on umbilical cord serum concentrations of retinol-binding protein (serum t 1/2 = 12 h), transthyretin (t 1/2 = 2 days), transferrin (t 1/2 = 8 days), retinol (vitamin A), and vitamin E in appropriate-for-gestational-age preterm newborn infants of less than 36 weeks' gestation. A group of 30 infants whose mothers received a single course of betamethasone less than or equal to 1 week prior to delivery had significantly elevated mean retinol-binding protein and transthyretin but not transferrin concentrations when compared with a group of 30 gestational age- and birth weight-matched infants with no exposure to antenatal betamethasone. A group of eight infants whose mothers received multiple (more than two) weekly courses of betamethasone prior to delivery had significantly elevated mean serum concentrations of all three proteins when compared with eight gestational age- and weight-matched control infants with no betamethasone exposure. Serum retinol and vitamin E concentrations were measured in a group of 21 infants exposed to short-term prenatal betamethasone and were significantly greater than in a group of 21 control infants without steroid exposure. We conclude that antenatal steroids increase the umbilical cord serum concentrations of retinol-binding protein, transthyretin, transferrin, retinol, and vitamin E. The effect on the various serum proteins is dependent on the duration of exposure to steroids.