Utilizing Pediatric Physiologically Based Pharmacokinetic Models to Examine Factors That Contribute to Methadone Pharmacokinetic Variability in Neonatal Abstinence Syndrome Patients.

Chronic intrauterine exposure to psychoactive drugs often results in neonatal abstinence syndrome (NAS). NAS is the symptomatic drug withdrawal in newborns that generally occurs after in utero chronic opioid exposure. Methadone is an opioid analgesic commonly prescribed for pharmacologic management of NAS. It exhibits high pharmacokinetic (PK) variability. The current study used physiologically based PK modeling to predict the PK profile of methadone in 20 newborns treated for NAS. The physiologically based PK simulations adequately predicted the PK profile of the clinical data for 45% of the patients. Sensitivity analyses were conducted to explore contributing factors to methadone PK variability. The data suggest that P450 enzymatic activity impacts the clearance of methadone in virtual adults and neonates, while the contribution of cardiac output may be negligible. Understanding maturational and/or pharmacogenetic changes in cytochrome P450 enzymatic activity may further explain the large PK variability of methadone in newborns with NAS and will help individualized treatment.

Can alpha-1-acid glycoprotein affect the outcome of treatment in a cancer patient?

Alpha-1-acid glycoprotein (AGP) is a glycoprotein found in the alpha-1 globulin fraction of human plasma proteins. AGP is an important representative of acute-phase proteins. Although numerous articles have been devoted to AGP, its exact biological function remains obscure. AGP levels increase with a number of diseases. One of them is a tumor disease. In our paper, we discuss the role of increased AGP levels in cancer patients. We deal with the role of AGP as a drug-binding protein and its effect on the efficacy of chemotherapy in oncological patients. Other problems that are discussed in our paper include the role of AGP as an immunomodulatory protein and its relationship to angiogenesis because angiogenesis plays an important role in the progression of cancer (Ref. 57). Keywords: alpha-1-acid glycoprotein, orosomucoid, cancer, disease marker, immunomodulatory protein,drug-binding protein.

The Acute-Phase Protein Orosomucoid Regulates Food Intake and Energy Homeostasis via Leptin Receptor Signaling Pathway.

The acute-phase protein orosomucoid (ORM) exhibits a variety of activities in vitro and in vivo, notably modulation of immunity and transportation of drugs. We found in this study that mice lacking ORM1 displayed aberrant energy homeostasis characterized by increased body weight and fat mass. Further investigation found that ORM, predominantly ORM1, is significantly elevated in sera, liver, and adipose tissues from the mice with high-fat diet (HFD)-induced obesity and db/db mice that develop obesity spontaneously due to mutation in the leptin receptor (LepR). Intravenous or intraperitoneal administration of exogenous ORM decreased food intake in C57BL/6, HFD, and leptin-deficient ob/ob mice, which was absent in db/db mice and was significantly reduced in mice with arcuate nucleus (ARC) LepR knockdown, whereas enforced expression of ORM1 in ARC significantly decreased food intake, body weight, and serum insulin level. Furthermore, we found that ORM is able to bind directly to LepR and activate the receptor-mediated JAK2-STAT3 signaling in hypothalamus tissue and GT1-7 cells, which was derived from hypothalamic tumor. These data indicated that ORM could function through LepR to regulate food intake and energy homeostasis in response to nutrition status. Modulating the expression of ORM is a novel strategy for the management of obesity and related metabolic disorders.

An acute-phase protein as a regulator of sperm survival in the bovine oviduct: alpha 1-acid-glycoprotein impairs neutrophil phagocytosis of sperm in vitro.

We have previously shown that polymorphonuclear neutrophils (PMNs) are present in bovine oviduct fluid under physiological conditions, and that the oviduct provides a microenvironment that protects sperm from phagocytosis by PMNs. Alpha 1-acid glycoprotein (AGP) is a major acute-phase protein produced mainly in the liver that has immunomodulatory functions. AGP mRNA is expressed in extrahepatic organs, such as the lung, kidney, spleen, lymph node, uterus, and ovary. Therefore, in this study, we investigated, 1) the local production of AGP in the bovine oviduct, 2) the effect of AGP on the phagocytic activity of PMNs for sperm and superoxide production and 3) the impact of AGP desialylation on the PMN phagocytosis of sperm. The AGP gene was expressed in cultured bovine oviduct epithelial cells (BOECs) and AGP protein was detected in oviduct fluid. Preexposure of PMNs to AGP at physiological levels impaired PMN phagocytosis for sperm and superoxide generation. The desialylation of AGP eliminated these suppressive effects of AGP on PMN. Scanning electron microscopy revealed that AGP drastically reduced the formation of DNA-based neutrophil extracellular traps (NETs) for sperm entanglement. Additionally, AGP dose-dependently stimulated BOECs to produce prostaglandin E2 (PGE2) which has been shown to partially contribute to the regulation of sperm phagocytosis in the bovine oviduct. AGP and PGE2 at concentrations detected in the oviducts additively suppressed sperm phagocytosis by PMNs. These results provide evidence that locally produced AGP may be involved in protecting sperm from phagocytosis by PMNs in the bovine oviduct.

Orosomucoid secretion levels by epicardial adipose tissue as possible indicator of endothelial dysfunction in diabetes mellitus or inflammation in coronary artery disease.

OBJECTIVE: Type 2 diabetes mellitus (T2DM) is associated with fat and autonomic system dysfunction. Epicardial adipose tissue (EAT) plays an endocrine role over the heart. Since orosomucoid (ORM) has local actions around the coronaries, our aim was to assess the relationship between its secretion profile by EAT and its catecholaminergic regulation in patients with T2DM and coronary artery disease (CAD). METHODS: We obtained EAT, subcutaneous adipose tissue (SAT) and plasma from 55 patients undergoing cardiac surgery. Fat explants were stimulated with isoproterenol (ISO) 1 µM for 6 h. After, the fat explants released-ORM and plasma levels were analyzed by ELISA. mRNA or protein expression was analyzed by real time PCR or western blot, respectively. The effects of ORM on endothelial cells were analyzed by impedance and wound healing assays. RESULTS: We observed that EAT-released ORM levels were higher than SAT (328 ± 185 vs 58 ± 45 ng/mL; p < 0.001). Interestingly, EAT secretion was lower in patients with than those without T2DM (260 ± 141 vs 370 ± 194 ng/mL; p < 0.05) and this difference was enhanced after ISO stimulation (p < 0.01). However, plasma levels (412 ± 119 vs 594 ± 207 µg/mL) and EAT-released ORM levels were higher in patients with than those without CAD (384 ± 195 vs 279 ± 159 ng/mL; p < 0.05). ISO stimulation, also reduced the EAT released-ORM levels in patients with CAD. On human endothelial cells, ORM induced an increase of healing and proliferation in a dose-dependent manner. CONCLUSION: EAT-released ORM levels in patients with T2DM or CAD and its regulation by catecholamines might be the mirror of local endothelium dysfunction or inflammatory process in different cardiovascular disorders.

The acute phase reactant orosomucoid-1 is a bimodal regulator of angiogenesis with time- and context-dependent inhibitory and stimulatory properties.

BACKGROUND: Tissues respond to injury by releasing acute phase reaction (APR) proteins which regulate inflammation and angiogenesis. Among the genes upregulated in wounded tissues are tumor necrosis factor-alpha (TNFα) and the acute phase reactant orosomucoid-1 (ORM1). ORM1 has been shown to modulate the response of immune cells to TNFα, but its role on injury- and TNFα-induced angiogenesis has not been investigated. This study was designed to characterize the role of ORM1 in the angiogenic response to injury and TNFα. METHODS AND RESULTS: Angiogenesis was studied with in vitro, ex vivo, and in vivo angiogenesis assays. Injured rat aortic rings cultured in collagen gels produced an angiogenic response driven by macrophage-derived TNFα. Microarray analysis and qRT-PCR showed that TNFα and ORM1 were upregulated prior to angiogenic sprouting. Exogenous ORM1 delayed the angiogenic response to injury and inhibited the proangiogenic effect of TNFα in cultures of aortic rings or isolated endothelial cells, but stimulated aortic angiogenesis over time while promoting VEGF production and activity. ORM1 inhibited injury- and TNFα-induced phosphorylation of MEK1/2 and p38 MAPK in aortic rings, but not of NFκB. This effect was injury/TNFα-specific since ORM1 did not inhibit VEGF-induced signaling, and cell-specific since ORM1 inhibited TNFα-induced phosphorylation of MEK1/2 and p38 MAPK in macrophages and endothelial cells, but not mural cells. Experiments with specific inhibitors demonstrated that the MEK/ERK pathway was required for angiogenesis. ORM1 inhibited angiogenesis in a subcutaneous in vivo assay of aortic ring-induced angiogenesis, but stimulated developmental angiogenesis in the chorioallantoic membrane (CAM) assay. CONCLUSION: ORM1 regulates injury-induced angiogenesis in a time- and context-dependent manner by sequentially dampening the initial TNFα-induced angiogenic response and promoting the downstream stimulation of the angiogenic process by VEGF. The context-dependent nature of ORM1 angioregulatory function is further demonstrated in the CAM assay where ORM1 stimulates developmental angiogenesis without exerting any inhibitory activity.

Genomic biomarkers and cellular pathways of ischemic stroke by RNA gene expression profiling.

OBJECTIVE: The objective of this study was to provide insight into the molecular mechanisms of acute ischemic cerebrovascular syndrome (AICS) through gene expression profiling and pathway analysis. METHODS: Peripheral whole blood samples were collected from 39 MRI-diagnosed patients with AICS and 25 nonstroke control subjects ≥ 18 years of age. Total RNA was extracted from whole blood stabilized in Paxgene RNA tubes, amplified, and hybridized to Illumina HumanRef-8v2 bead chips. Gene expression was compared in a univariate manner between stroke patients and control subjects using t test in GeneSpring. The significant genes were tested in a logistic regression model controlling for age, hypertension, and dyslipidemia. Inflation of type 1 error was corrected by Bonferroni and Ingenuity Systems Pathway analysis was performed. Validation was performed by QRT-PCR using Taqman gene expression assays. RESULTS: A 9-gene profile was identified in the whole blood of ischemic stroke patients using gene expression profiling. Five of these 9 genes were identified in a previously published expression profiling study of stroke and are therefore likely biomarkers of stroke. Pathway analysis revealed toll-like receptor signaling as a highly significant canonical pathway present in the peripheral whole blood of patients with AICS. CONCLUSIONS: Our study highlights the relevance of the innate immune system through toll-like receptor signaling as a mediator of response to ischemic stroke and supports the claim that gene expression profiling can be used to identify biomarkers of ischemic stroke. Further studies are needed to validate and refine these biomarkers for their diagnostic potential.

[Study on binding of drug to serum protein].

After being distributed in the circulating blood, drugs bind to serum proteins varying degrees. In general, such binding is reversible, and a dynamic equilibrium exists between the bound and unbound molecular species. It is believed that unless there is a specific transport system (e.g. receptor-mediated endocytosis, protein-mediated transport), only unbound drugs are able to penetrate through biomembranes, are distributed to tissues, and undergo metabolism and glomerular filtration. It is also believed that only unbound molecules present in target tissues can exert their pharmacological effects, and that the concentration of unbound molecules in tissues is in proportion to the drug serum concentration. Therefore, drug-serum protein binding is critically involved in the manifestation of the pharmacological effects of a drug as well as its pharmacokinetics. Among serum proteins, human serum albumin (HSA) and alpha(1)-acid glycoprotein (AGP) play important roles in protein binding for many drugs, which is of key importance to drug distribution in the body. In addition, they are widely used in clinical settings as blood preparations and drug delivery system carriers. It is thus of great importance from the viewpoint of pharmaceutical science to clarify the structure, function, and pharmaceutical properties of HSA and AGP. Accordingly, since starting my laboratory, the focus of my research has involved molecular pharmaceutical studies on the interactions of drugs and HSA and AGP for the purpose of applying these findings to clinical fields, such as drug treatment, diagnosis and drug discovery. In this review, the molecular properties of HSA and AGP will be briefly outlined. The static and dynamic topology of drug binding sites on these proteins, investigated by various spectroscopic techniques, X-ray crystallography, quantitative structure-activity relationships, molecular modeling, photo affinity labeling, site-directed mutagenesis etc., changes in the serum protein binding of drugs in pathological conditions, such as liver and kidney failure and various inflammation diseases and factors contributing to the changes will then be summarized. Finally, cases in which protein binding displacement can be applied to medical fields will also be introduced.

Acute-phase protein alpha-1-acid glycoprotein mediates neutrophil migration failure in sepsis by a nitric oxide-dependent mechanism.

The reduction of circulating neutrophil migration to infection sites is associated with a poor outcome of severe sepsis. alpha-1-Acid glycoprotein (AGP) was isolated from the sera of severely septic patients by HPLC and acrylamide gel electrophoresis and identified by mass spectrometry. Both the isolated protein and commercial AGP inhibited carrageenin-induced neutrophil migration into the rat peritoneal cavity when administered i.v. at a dose of 4.0 microg per rat (95 pmol per rat). Analysis by intravital microscopy demonstrated that both proteins inhibited the rolling and adhesion of leukocytes in the mesenteric microcirculation. The inhibitory activity was blocked by 50 mg/kg aminoguanidine, s.c., and was not demonstrable in inducible nitric oxide synthase (iNOS) knockout mice. Incubation of AGP with neutrophils from healthy subjects induced the production of NO and inhibited the neutrophil chemotaxis by an iNOS/NO/cyclic guanosine 3,5-monophosphate-dependent pathway. In addition, AGP induced the l-selectin shedding by neutrophils. The administration of AGP to rats with mild cecal ligation puncture sepsis inhibited neutrophil migration and reduced 7-day survival from approximately 80% to 20%. These data demonstrate that AGP, an acute-phase protein, inhibits neutrophil migration by an NO-dependent process and suggest that AGP also participates in human sepsis.

Role of alpha1-acid glycoprotein in therapeutic antifibrotic effects of imatinib with macrolides in mice.

RATIONALE: Imatinib is an inhibitor of platelet-derived growth factor receptors. We have reported that treatment with imatinib inhibited bleomycin-induced pulmonary fibrosis in mice. However, late treatment with imatinib had no effect. OBJECTIVES: To clarify why imatinib had no antifibrotic effect when its administration was delayed, we focused on alpha(1)-acid glycoprotein (AGP), because it was reported to bind imatinib and mediate drug resistance. METHODS: The concentration of AGP in serum of mice and patients with idiopathic pulmonary fibrosis was measured by radial immunodiffusion testing. The effects of AGP in vitro were evaluated by assaying the growth of lung fibroblasts. We examined the combined effects of erythromycin (EM) or clarithromycin (CAM) on bleomycin-induced pulmonary fibrosis in mice. MEASUREMENTS AND MAIN RESULTS: Addition of AGP abrogated imatinib-mediated inhibition of the growth of fibroblasts. However, treatment with EM or CAM restored the growth-inhibitory effects of imatinib. The elevated level of AGP was detected in serum and lung homogenates in bleomycin-exposed mice and reached a plateau on Day 14. Imatinib alone did not ameliorate pulmonary fibrosis when treatment was started on Day 15, whereas coadministration of imatinib and EM or CAM significantly reduced the fibrogenesis via inhibition of the growth of fibroblasts in vivo. Serum levels of AGP were higher in patients with idiopathic pulmonary fibrosis than in healthy subjects. CONCLUSIONS: AGP is an important regulatory factor modulating the ability of imatinib to prevent pulmonary fibrosis in mice, and combined therapy with imatinib and EM or CAM might be useful for treatment of pulmonary fibrosis.

The acute-phase protein alpha 1-acid glycoprotein (AGP) induces rises in cytosolic Ca2+ in neutrophil granulocytes via sialic acid binding immunoglobulin-like lectins (siglecs).

We studied whether the acute-phase protein alpha1-acid glycoprotein (AGP) induces rises in [Ca2+]i in neutrophils and sought to identify the corresponding AGP receptor (or receptors). We found that AGP elicited a minimal rise in [Ca2+]i in Fura-2-loaded neutrophils, and this response was markedly enhanced by pretreatment with anti-L-selectin antibodies. (The EC50 value of the AGP-induced Ca2+ response was 9 microg/ml.) Activation of phospholipase-C, Src tyrosine kinases, and PI3 kinases proved to be essential for the AGP-mediated increase in [Ca2+]i, whereas the p38 MAPK and SYK signaling pathways were not involved. Furthermore, antibodies against sialic acid binding, immunoglobulin-like lectin 5 (Siglec-5) and oligosaccharide 3'-sialyl-lactose both antagonized the AGP-induced response and caused an immediate increase in [Ca2+]i in anti-L-selectin-treated neutrophils, which indicates a signaling capacity of Siglec-5. We used modified forms of AGP (treated with mild periodate or neuraminidase) to establish the importance of sialic acid residues. The modified forms of AGP caused a much smaller rise in [Ca2+]i than did unaltered AGP. Affinity chromatography confirmed that unchanged AGP, but not neuraminidase-treated AGP, bound to Siglec-5. Our report provides the first evidence for a signaling capacity by AGP through a defined receptor. Pre-engagement of L-selectin significantly enhanced this signaling capacity.

Cutting edge: IPSE/alpha-1, a glycoprotein from Schistosoma mansoni eggs, induces IgE-dependent, antigen-independent IL-4 production by murine basophils in vivo.

During infection with the helminth parasite Schistosoma mansoni, the deposition of eggs coincides with the onset of IL-4 production and Th2 development. Although IL-4 is known as a potent inducer of Th2 differentiation, the mechanism by which schistosome eggs induce IL-4 production is not clear. In this study, we demonstrate that the S. mansoni egg Ag (SmEA) induces IgE-dependent IL-4 production by basophils derived from Heligmosomoides polygyrus-infected or OVA/alum-immunized mice in the absence of pathogen-specific IgE. The effect is mediated by the secretory glycoprotein IPSE/alpha-1, because IPSE/alpha-1-depleted SmEA no longer induces cytokine production. Conversely, recombinant IPSE/alpha-1 is sufficient to induce IL-4 production. Importantly, the injection of SmEA or recombinant IPSE/alpha-1 into H. polygyrus-infected 4get/KN2 IL-4 reporter mice rapidly induces the dose-dependent IL-4 production by basophils in the liver, a major site of egg deposition. Thus, IPSE/alpha-1 induces basophils to produce IL-4 even in the absence of Ag-specific IgE.

alpha(1)-Acid glycoprotein modulates apoptosis in bovine monocytes.

alpha(1)-Acid glycoprotein (AGP, orosomucoid) is a normal constituent of bovine blood. AGP is an immunocalin, a binding protein that can also exert several immunomodulatory functions. In this paper we investigated the effect of bovine alpha(1)-acid glycoprotein (boAGP) on spontaneous and staurosporine-induced apoptosis of blood derived monocytes purified using magnetic cell sorting techniques. Bovine AGP was purified from blood following a chromatographic protocol. The homogeneous protein was used to stimulate the cells as well to raise a polyclonal antibody, that was used throughout all the experiments. When monocytes were incubated with high concentrations of boAGP (0.9 mg/ml), similar to those found in bovine plasma during systemic reaction to inflammation, their spontaneous apoptosis rate was suppressed, as determined by caspase-3/7 enzymatic activity assay. Similar results were obtained when apoptosis was induced by adding staurosporine, a potent protein kinase inhibitor. The apoptosis-modulating activity of boAGP was dependent on its concentration, since physiological concentrations of boAGP (0.3 mg/ml) did not exhibit a statistically significative anti-apoptotic activity. We also investigated whether this apoptosis-modulating activity was dependent on the terminal sialic acid residues exposed on the surface of the protein. Enzymatic treatment with neuraminidase, that cleaves terminal sialic acid residues, completely abolished boAGP's anti-apoptotic activity. These results suggest that the protective effect of AGP is likely mediated by its sialic acid terminal groups.

Biochemical and chemical supports for a transnatal olfactory continuity through sow maternal fluids.

Recognition of the mother is of major importance for the survival of mammalian neonates. This recognition is based, immediately after birth, on the detection of odours that have been learned by the fetus in utero. If the ethological basis of a transnatal olfactory continuity is well established, little is known on the nature of its olfactory cues, and nothing about the presence of potential carrier proteins in the maternal fluids such as amniotic fluid, colostrum and milk. We have identified the components of the pig putative maternal pheromone in these fluids of the sow. We also used a ligand-oriented approach to functionally characterize carrier proteins for these compounds in the maternal fluids. Six proteins were identified, using binding assay, immunodetection and peptide mapping by mass spectrometry. These proteins are known to transport hydrophobic ligands in biological fluids. Among them, alpha-1 acid glycoprotein (AGP) and odorant-binding protein (OBP) have been described in the oral sphere of piglets as being involved in the detection of pig putative maternal pheromone components. These are the first chemical and biochemical data supporting a transnatal olfactory continuity between the fetal and the postnatal environments.

Effects of alpha(1)-acid glycoprotein on isometric tension of mouse aorta.

We examined the effects of human alpha(1)-acid glycoprotein on isometric tension of mouse aortic rings. alpha(1)-Acid glycoprotein (7.5-75 microM) produced a transient, concentration-dependent relaxation of the phenylephrine-precontracted preparation. Although N(G)-nitro-L-arginine methyl ester or removal of endothelium rarely affected the alpha(1)-acid glycoprotein-induced relaxation, extracellular heparin inhibited the alpha(1)-acid glycoprotein-induced relaxation. In 10 mM Ca(2+)-containing external solutions, the alpha(1)-acid glycoprotein-induced relaxation was significantly potentiated. In the 60 mM KCl-precontracted preparation, alpha(1)-acid glycoprotein produced weaker relaxation than in the phenylephrine-precontracted preparation. These results suggest that the vasorelaxant effect of alpha(1)-acid glycoprotein is mainly achieved by block of Ca(2+) entry in the vascular smooth muscle cells. The interaction between alpha(1)-acid glycoprotein molecules and plasmalemmal Ca(2+) entry channels may be modified by extracellular Ca(2+) and heparin.

Functional characterization of olfactory binding proteins for appeasing compounds and molecular cloning in the vomeronasal organ of pre-pubertal pigs.

The appeasing behaviour of pre-pubertal pigs appears to result from the perception of maternal odours (fatty acids) and of steroids coming from the male. We have used a ligand-oriented approach to functionally characterize olfactory binding proteins involved in the detection of appeasing compounds in the nasal mucosa (NM) and the vomeronasal organ (VNO) of pre-pubertal pigs. Several proteins were identified, combining binding assay, immunodetection and protein sequencing. Their sites of expression in nasal and vomeronasal tissues were studied by reverse transcription polymerase chain reaction (RT-PCR). The proteins belong to the lipocalin superfamily: Alpha-1-acid glycoprotein (AGP), odorant-binding protein (OBP), salivary lipocalin (SAL) and Von Ebner's gland protein (VEG), and displayed different binding capacities for the appeasing compounds. RT-PCR experiments showed that OBP and VEG are expressed not only in the NM, but also in the VNO and that SAL is only expressed in the VNO. This is the first report of the expression of these lipocalins in the VNO. Different binding affinities between lipocalins and appeasing compounds, together with their different localizations in the olfactory systems, suggest multiple possibilities for the peripheral coding of appeasing signals.

Alpha1-acid glycoprotein expressed in the plasma of chronic myeloid leukemia patients does not mediate significant in vitro resistance to STI571.

Despite the efficacy of STI571 (Glivec, Novartis, Basle, Switzerland) in treating chronic myeloid leukemia (CML), drug resistance has already been noted both in vitro and in vivo. As plasma proteins, including alpha-1-acid glycoprotein (AGP), may reduce drug efficacy through binding, AGP was investigated for its ability to interact with STI571. At all stages of CML, AGP plasma level was significantly higher than in normal controls (P <.05). The glycoprotein was purified from normal plasma and individual chronic myeloid leukemia (CML) patients' plasma by low-pressure chromatography. The influence of alpha1-acid glycoprotein (AGP), in the presence of STI571, on the proliferation of Philadelphia chromosome-positive (Ph+) cells was examined. Normal AGP, even at supraphysiological concentrations, did not block the effect of STI571 on K562-cell proliferation in vitro. Moreover, CML-derived AGP failed to block the effect of STI571 on Ph+ cells in vitro. Thus, these in vitro findings suggest that AGP will not abrogate the antileukemic activity of STI571.

Alpha-1-acid glycoprotein.

Alpha-1-acid glycoprotein (AGP) or orosomucoid (ORM) is a 41-43-kDa glycoprotein with a pI of 2.8-3.8. The peptide moiety is a single chain of 183 amino acids (human) or 187 amino acids (rat) with two and one disulfide bridges in humans and rats,respectively. The carbohydrate content represents 45% of the molecular weight attached in the form of five to six highly sialylated complex-type-N-linked glycans. AGP is one of the major acute phase proteins in humans, rats, mice and other species. As most acute phase proteins, its serum concentration increases in response to systemic tissue injury, inflammation or infection, and these changes in serum protein concentrations have been correlated with increases in hepatic synthesis. Expression of the AGP gene is controlled by a combination of the major regulatory mediators, i.e. glucocorticoids and a cytokine network involving mainly interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF alpha), interleukin-6 and IL-6 related cytokines. It is now well established that the acute phase response may take place in extra-hepatic cell types, and may be regulated by inflammatory mediators as observed in hepatocytes. The biological function of AGP remains unknown; however,a number of activities of possible physiological significance, such as various immunomodulating effects, have been described. AGP also has the ability to bind and to carry numerous basic and neutral lipophilic drugs from endogenous (steroid hormones) and exogenous origin; one to seven binding sites have been described. AGP can also bind acidic drugs such as phenobarbital. The immunomodulatory as well as the binding activities of AGP have been shown to be mostly dependent on carbohydrate composition. Finally, the use of AGP transgenic animals enabled to address in vivo, functionality of responsive elements and tissue specificity, as well as the effects of drugs that bind to AGP and will be an useful tool to determine the physiological role of AGP.