Neurite Growth and Polarization on Vitronectin Substrate after in Vitro Trauma is not Enhanced after IGF Treatment.

Following traumatic brain injuries (TBI), insulin-like growth factor (IGF) is cortically widely upregulated. This upregulation has a potential role in the recovery of neuronal tissue, plasticity, and neurotrophic activity, though the molecular mechanisms involved in IGF regulation and the exact role of IGF after TBI remain unclear. Vitronectin (VN), an extracellular matrix (ECM) molecule, has recently been shown to be of importance for IGF-mediated cellular growth and migration. Since VN is downregulated after TBI, we hypothesized that insufficient VN levels after TBI impairs the potential beneficial activity of IGF. To test if vitronectin and IGF-1/IGFBP-2 could contribute to neurite growth, we cultured hippocampal neurons on ± vitronectin-coated coverslips and them treated with ± IGF-1/IGF binding protein 2 (IGFBP-2). Under same conditions, cell cultures were also subjected to in vitro trauma to investigate differences in the posttraumatic regenerative capacity with ± vitronectin-coated coverslips and with ± IGF-1/IGFBP-2 treatment. In both the control and trauma situations, hippocampal neurons showed a stronger growth pattern on vitronectin than on the control substrate. Surprisingly, the addition of IGF-1/IGFBP-2 showed a decrease in neurite growth. Since neurite growth was measured as the number of neurites per area, we hypothesized that IGF-1/IGFBP-2 contributes to the polarization of neurons and thus induced a less dense neurite network after IGF-1/IGFBP-2 treatment. This hypothesis could not be confirmed and we therefore conclude that vitronectin has a positive effect on neurite growth in vitro both under normal conditions and after trauma, but that addition of IGF-1/IGFBP-2 does not have a positive additive effect.

Mason type IV fractures of the elbow: a 14- to 46-year follow-up study.

A total of 14 women and seven men with a mean age of 43 years (18 to 68) who sustained a Mason type IV fracture of the elbow, without an additional type II or III coronoid fracture, were evaluated after a mean of 21 years (14 to 46). Primary treatment included closed elbow reduction followed by immobilisation in a plaster in all cases, with an additional excision of the radial head in 11, partial resection in two and suturing of the annular ligament in two. Delayed radial head excision was performed in two patients and an ulnar nerve transposition in one. The uninjured elbows served as controls. Nine patients had no symptoms, 11 reported slight impairment, and one severe impairment of the elbow. Elbow flexion was impaired by a mean of 3 degrees (sd 4) and extension by a mean of 9 degrees (sd 4) (p < 0.01). None experienced chronic elbow instability or recurrent dislocation. There were more degenerative changes in the formerly injured elbows, but none had developed a reduction in joint space. We conclude that most patients with a Mason type IV fracture of the elbow report a good long-term outcome.

Toxicity evaluation of PEDOT/biomolecular composites intended for neural communication electrodes.

Electrodes coated with the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT) possess attractive electrochemical properties for stimulation or recording in the nervous system. Biomolecules, added as counter ions in electropolymerization, could further improve the biomaterial properties, eliminating the need for surfactant counter ions in the process. Such PEDOT/biomolecular composites, using heparin or hyaluronic acid, have previously been investigated electrochemically. In the present study, their biocompatibility is evaluated. An agarose overlay assay using L929 fibroblasts, and elution and direct contact tests on human neuroblastoma SH-SY5Y cells are applied to investigate cytotoxicity in vitro. PEDOT:heparin was further evaluated in vivo through polymer-coated implants in rodent cortex. No cytotoxic response was seen to any of the PEDOT materials tested. The examination of cortical tissue exposed to polymer-coated implants showed extensive glial scarring irrespective of implant material (Pt:polymer or Pt). However, quantification of immunological response, through distance measurements from implant site to closest neuron and counting of ED1+ cell density around implant, was comparable to those of platinum controls. These results indicate that PEDOT:heparin surfaces were non-cytotoxic and show no marked difference in immunological response in cortical tissue compared to pure platinum controls.

Autoreactive antibodies against neurons and basal lamina found in serum following experimental brain contusion in rats.

BACKGROUND: Brain trauma is a risk factor for delayed CNS degeneration which may be attenuated by anti-inflammatory treatment. CNS injuries may cause anti-brain reactivity. This study was undertaken to analyze the pattern of delayed post-traumatic anti-brain immunity in experimental brain contusion. METHOD: Adult Sprague-Dawley and Lewis rats were subjected to experimental brain contusions. For B-cell investigations, serum was obtained from contused, control and naïve rats, and used for immunohistochemistry on slices of rat brains to first detect autoreactive IgG and IgM antibodies in rat serum. Secondly, anti-rat IgG and IgM antibodies were used to search for auto-antibodies already bound to the brain tissue. Double staining with rat-serum and NeuN or anti-GFAP antibody was used to detect anti-neuronal and anti-astrocytic antibodies, respectively. For T-cell reactivity, cells from brains and cervical lymph nodes of rats were used in FACS analysis and elispot with MBP and MOG stimulation. FINDINGS: Anti-vascular basal lamina IgG antibodies were detected at three months in 6/8 rats, following experimental contusion. Anti-neuronal IgG antibodies were detected 2 weeks after experimental contusion and sham surgery, while naïve controls were negative. Individual rats showed a prolonged response, or an anti-astrocytic staining. Tissue bound anti-self IgG or IgM was not detected in the brain tissue. Anti-MBP or anti-MOG T-cell responses were not detectable. CONCLUSIONS: Experimental brain trauma and to some degree even sham surgery lead to an individually variable pattern of specific anti-brain reactive B-cells, while a T-cell response did not seem to be a consequence of moderate experimental contusion. The mere presence of anti brain-antibodies may be epiphenomenal, but could also be pathogenic for delayed degeneration. It is reasonable to regard the presence of an actual anti-brain reactivity as a potential threat to brain tissue integrity.

Reducing the total discharge from a large WWTP by separate treatment of primary effluent overflow.

At many large wastewater treatment plants (WWTPs) the increased hydraulic load, caused by combined sewer systems during storm events, results in primary effluent overflow when the capacity of further treatment is exceeded. Due to stringent effluent standards, regulating the total discharge from the WWTPs, the Rya WWTP in Göteborg and the Sjölunda WWTP in Malmö will have to reduce the impact of primary effluent overflow. Separate, high rate, precipitation processes operated only during high flow conditions have been investigated in pilot units at the two WWTPs. Precipitation in existing primary settlers operated at a surface loading of 3.75 m/h removed phosphorus to 0.35 mg/l. The Actiflo process was also shown to remove suspended solids and phosphorus well. BOD was reduced by 50-60%. With such processes the overall effluent concentrations from the plants can be reduced significantly. Key upgrading features are small footprints, short start up time and high efficiency.

Dynamics in maximal settling capacity in an activated sludge treatment plant with highly loaded secondary settlers.

Secondary settling dynamics at maximal capacity were investigated at a full scale wastewater treatment plant which utilizes a unique process solution incorporating pre-denitrification with post-nitrification in nitrifying trickling filters. Since nitrogen removal is greater when more secondary effluent is recirculated to the trickling filters, the secondary settlers generally operate at close to their maximal capacity. The settling and flocculation properties of the activated sludge are therefore a major capacity-determining factor for plant operation. Due to the short sludge age, the flocculation properties, with respect to both thickening and clarification, can change quickly. The dynamics in these changes were studied and the factors that determine the maximal settling capacity were assessed. Solids flux curves were constructed from batch settling tests and compared with the actual maximal settling capacities.

Increased fragility in patients with fracture of the proximal humerus: a case control study.

The aim of this study was to evaluate whether a fracture of the proximal humerus is associated with an increased prevalence of preceding fractures or a risk of subsequent fractures. All patients who were treated at the Malmö General Hospital in 1987 for a fresh fracture of the proximal humerus were identified, representing practically all fractures of the proximal humerus in Malmö city (250,000) that year. Two hundred fifty-three adult patients, 54 men with an average age of 66 (24-90) and 199 women with a mean age of 74 (22-98) years, were included in the study together with 475 age- and gender-matched control persons. In 1999, fracture prevalence of patients and controls were rated by a survey at the Dept. of Radiology. There was a significantly increased prevalence of previous fractures before 1987 in the humerus fracture group with an odds ratio (OR) of 3.5 [95% confidence interval (95% CI), 2.2-5.5] for a spinal fracture, OR 1.8 (95% CI, 1.3-2.6) for a previous fracture to the upper extremity, and OR 1.8 (95% CI, 1.2-2.6) for a preceding fracture of the lower limb. The proximal humerus fracture also predicted a significantly increased risk of a subsequent fracture. The hazard ratio (HR) was 2.5 (95% CI, 1.7-3.7) for a forthcoming spinal fracture, HR 2.8 (95% CI, 2.0-3.7) for a future fracture of the upper extremity, and HR 2.0 (95% CI, 1.2-3.5) for a lower limb fracture. In a subgroup of male patients, an almost five times increased risk of sustaining subsequent extremity fractures was observed. In summary, a fracture of the proximal humerus is associated both with increased prevalence of previous fractures of the spine and extremities and also predicting an increased risk of future fractures.

Increased expression of vascular endothelial growth factor in human skeletal muscle in response to short-term one-legged exercise training.

The effects of short-term exercise training on vascular endothelial growth factor (VEGF) and one of its regulatory transcription factors, the hypoxia inducible factor 1 (HIF-1) subunit, were studied in eight healthy males. Muscle and blood samples were obtained before the 1st, and 24 h after the 7th training session. VEGF and HIF-1 mRNA were analysed using RT-PCR, VEGF mRNA localization with in situ hybridization and VEGF protein with ELISA. Concurrent increases in VEGF mRNA and protein levels were observed in skeletal muscle, and the mRNA was expressed within the skeletal muscle fibres and in cells in the interstitium. These data support the idea of a pretranslational regulation of exercise-induced changes in VEGF mRNA, and indicate that increased VEGF protein expression is an early event in skeletal muscle adaptation to training. Furthermore, different cell types may act as sources for the production of angiogenic factors in response to exercise. The levels of HIF-1 mRNA subunits did not change, suggesting no change in HIF-1 mRNA transcript levels in the regulation of training-induced VEGF expression. In contrast to increased tissue VEGF expression, the arterial and femoral venous plasma levels of VEGF were decreased by training, which may indicate an exercise-induced enhancement of the peripheral uptake of VEGF.

Expression of matrix metalloproteinases 2 and 9 in meningiomas associated with different degrees of brain invasiveness and edema.

OBJECT: Meningiomas display clinical characteristics that vary from very benign to clearly malignant with rapid invasive growth and metastasis. Benign meningiomas differ in their invasiveness and concomitant edema. This study was undertaken to analyze the expression of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9, respectively) in meningiomas associated with different degrees of brain invasion and edema. METHODS: Tissue samples from 16 meningiomas were selected according to tumor invasiveness from a consecutive series of patients. Samples were analyzed for expression of both MMP-2 and MMP-9 by using in situ hybridization. The meningiomas consisted of three types: Group I, benign meningiomas that did not interfere with the arachnoid plane and exhibited no edema; Group II, benign meningiomas that invaded the arachnoid plane and caused edema; and Group III, aggressive and malignant meningiomas that caused edema and displayed brain invasion. In all 16 tumors analyzed, MMP-2 mRNA was identified. Levels of expression of MMP-2 mRNA were similar in all samples, and no correlation with increasing tumor invasiveness or associated edema could be detected. Expression of MMP-9 mRNA was identified in 14 of the 16 tumors, and a clear correlation with increasing tumor invasion into the brain was noted. CONCLUSIONS: Meningiomas express both MMP-2 and MMP-9. Tumor invasiveness, which ranged from minor with respect to the arachnoid membrane and progressed to frank brain invasion, correlated with the extent of MMP-9 expression. The findings indicate that MMP-9 expression and brain invasion are relevant mechanisms that must be interfered with in the treatment of aggressive and malignant meningiomas. No such correlation with MMP-2 was found.

Induction of astrocytic nestin expression by depolarization in rats.

Nestin is expressed in central nervous system (CNS) progenitor cells and its expression in mature cells represents transition to a less differentiated cellular state under cellular stress. This study was performed to corroborate the hypothesis that nestin synthesis is induced by depolarization and dependent on N-methyl-D-aspartate (NMDA)-receptor activation. Depolarization was induced with application of potassium chloride on the exposed rat cortex and nestin expression was evaluated by immunohistochemistry. Depolarization induced astrocytic nestin expression that was local, or evident in the entire ipsilateral cortex depending on the time of exposure. Nestin expression was NMDA-receptor-dependent since MK-801 treatment abolished the response. Understanding the mechanisms for nestin expression is important since this protein is expressed in reactive and less differentiated CNS cell states and also in neural stem cells. Insights into the control of nestin expression may also provide means for controlling differentiation of CNS cells either post-trauma/ischemia or in transplantation strategies.

Insulin-like growth factor-II in endocrine pancreatic tumours. Immunohistochemical, biochemical and in situ hybridization findings.

In earlier studies a high-molecular-weight (HMW) insulin-like growth factor-II (IGF-II) peptide was identified in adult human pancreas and localized to the insulin-producing B-cells. This peptide has now been investigated in neoplastic insulin cells. Forty endocrine pancreatic tumours and 17 pancreatic adenocarcinomas of ductal type were included in the study. All cases were investigated with immunohistochemical techniques using antibodies to IGF-II, insulin, pro-insulin, glucagon, somatostatin, pancreatic polypeptide, gastrin and vasoactive intestinal peptide (VIP). Frozen tissue from nine tumours and two normal pancreatic glands was extracted, gel separated, and quantified using radioimmunoassay. The tumours were also investigated by in situ hybridization. IGF-II-immunoreactive cells were found in nearly all the 18 insulin-producing tumours (16/18), in a minority of the other endocrine tumours, but not in pancreatic adenocarcinomas. All extracts from the endocrine tumours showed varying amounts of IGF-II and had different molecular-weight forms. The immunohistochemical and radioimmunoassay findings are both based on immunological binding and were further confirmed by Northern blot and in situ hybridization. These results show that IGF-II is expressed in insulin-producing tumours as well as in pancreatic tumours producing other peptides, in contrast to normal pancreatic islets where IGF-II is found exclusively in insulin-producing cells.

Depolarization induces insulin-like growth factor binding protein-2 expression in vivo via NMDA receptor stimulation.

The effect of depolarization and N-methyl-D-aspartate (NMDA) receptor blockade on insulin-like growth factor-I (IGF-I), IGF binding protein-2 (IGFBP-2) and IGFBP-4 expression was analysed in vivo. Depolarization was induced in adult rat brains by applying 3 M KCl to the exposed cortex for 10 min. A subgroup of animals also received daily injections of MK-801. Four days after KCl exposure, the brains were analysed by in situ hybridization, immunohistochemistry and TUNEL. A significant upregulation of IGFBP-2 mRNA and protein was detected in astrocytes after KCl exposure This upregulation was reduced by MK-801 treatment. No alterations in IGF-I or IGFBP-4 mRNA levels were noted. We did not detect TUNEL positive cells, morphological signs of necrosis or apoptosis, or neuronal loss in the depolarized zone. Taken together, these findings indicate that upregulation of IGFBP-2 by depolarization is mediated by NMDA receptors, and, as no neuronal damage was detected, astrocytic NMDA receptors may be responsible for this upregulation.

Fewer problems with dry nasal mucous membranes following local use of sesame oil.

Many people experience problems with a dry nasal mucous membrane, often without wondering why. Their noses itch and burn and dried mucus collects there. These problems are exacerbated during the winter, in air-conditioned environments and after nasal irradiation. Twenty patients experiencing problems with dryness of the nose were selected from outpatient clinics, together with twenty patients who had previously undergone nasal irradiation. During the first five days no treatment was administered. For the following twenty days the patients sprayed sesame oil into each nostril three times a day. For the last five days no treatment was given. When both groups received treatment and sprayed sesame oil (Nozoil) in their noses, the nasal problems decreased significantly. The greatest effect is exerted on dryness. The side effects from using this oil are few in number and mild.

Age-dependent expression of protein phosphatase 2A in the developing rat kidney.

Several lines of evidence suggest that the serine/threonine protein phosphatase (PP)2A is of vital importance for cell cycle regulation, cell differentiation, and signal transduction. This prompted us to study the expression of the mRNA for PP2A catalytic isoforms alpha and beta in the developing rat kidney using in situ hybridization histochemistry. The expression patterns of the two isoforms were strikingly similar. Both were ubiquitously expressed in early metanephric kidneys. Later in gestation they were expressed in the nephrogenic zone. Strong expression was observed on postnatal day (PN) 10. This was followed by a downregulation at PN20, i.e., when nephrogenesis is completed. The expression in the adult kidney was very weak and mainly confined to the medulla. In a phosphatase activity assay, PP2A accounted for 78% of the total serine/threonine phosphatase activity in embryonic day 15 rat kidneys. PP1 was the main contributor to the remaining activity. In conclusion, PP2A is the major serine/threonine phosphatase in fetal kidneys. The age-dependent expression pattern supports the concept that this enzyme is of particular importance during renal morphogenesis and development.

The megencephaly mouse has disturbances in the insulin-like growth factor (IGF) system.

Megencephaly, enlarged brain, is a major sign in several human neurological diseases. The mouse model for megencephaly, mceph/mceph, has an enlarged brain and a lowered body weight. In addition, it displays several neurological and motoric disturbances. Previous studies suggest that the brain enlargement results from hypertrophy of the brain cells, rather than hyperplasia. No structural abnormalities, edema or increased myelination have been found. In this study, a major imbalance in the mRNA expression of molecules in the insulin-like growth factor (IGF) system was found in brains of 9-10 weeks old mceph/mceph mice compared to +/+ wild-type mice. In mceph/mceph brains, we found upregulation of IGF binding proteins (BP)-2, -4, -5, and -6 mRNA, the regulating hormone transforming growth factor (TGF)beta1 mRNA and also a local downregulation of IGFBP-5 mRNA compared to wild-type brains by in situ hybridization. The altered expression of these mRNA species is colocalized in cerebral cortex, hippocampus, amygdala and piriform/entorhinal cortex. The mceph/mceph mice express less of the myelin component proteolipid protein (PLP) mRNA in corpus callosum. No expression difference of the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in brain or IGF system components in liver was found between mceph/mceph and wild-type mice. These data suggest that the IGF system has an important role in the excessive growth of the mceph/mceph brains.

TOM1 genes map to human chromosome 22q13.1 and mouse chromosome 8C1 and encode proteins similar to the endosomal proteins HGS and STAM.

The avian tom1 (target of myb 1) gene has been previously characterized from v-myb-transformed cells. We report here cloning of the human and mouse tom1 orthologs. Both genes are expressed ubiquitously, with the highest levels in skeletal muscle, brain, and intestines, as assessed by Northern blot and mRNA in situ hybridization. The N-terminal domain of the TOM1 protein shares similarity with HGS (hepatocyte growth factor-regulated tyrosine kinase substrate) and STAM (signal-transducing adaptor molecule), which are associated with vesicular trafficking at the endosome. A putative coiled-coil domain was also detected in the central part of the TOM1 protein. This domain structure suggests that TOM1 is another member of a family of genes implicated in the trafficking regulation of growth-factor-receptor complexes that are destined for degradation in the lysosome. We also show that a human paralog of TOM1 (TOM1-like gene 1) exists. Furthermore, we provide a transcription map over a 190-kb contig of the TOM1 region. This map includes its distal neighbors HMOX1 and MCM5 and two proximal novel genes, one of which is a HMG-box-containing gene (HMG2L1), and the other of unknown function. Using a genomic PAC clone, we demonstrate that the mouse Tom1 and Hmox1 genes are part of an as yet undescribed syntenic group between mouse chromosome 8C1 and human chromosome 22q13.1.

The human LARGE gene from 22q12.3-q13.1 is a new, distinct member of the glycosyltransferase gene family.

Meningioma, a tumor of the meninges covering the central nervous system, shows frequent loss of material from human chromosome 22. Homozygous and heterozygous deletions in meningiomas defined a candidate region of >1 Mbp in 22q12.3-q13.1 and directed us to gene cloning in this segment. We characterized a new member of the N-acetylglucosaminyltransferase gene family, the LARGE gene. It occupies >664 kilobases and is one of the largest human genes. The predicted 756-aa N-acetylglucosaminyltransferase encoded by LARGE displays features that are absent in other glycosyltransferases. The human like-acetylglucosaminyltransferase polypeptide is much longer and contains putative coiled-coil domains. We characterized the mouse LARGE ortholog, which encodes a protein 97.75% identical with the human counterpart. Both genes reveal ubiquitous expression as assessed by Northern blot analysis and in situ histochemistry. Chromosomal mapping of the mouse gene reveals that mouse chromosome 8C1 corresponds to human 22q12.3-q13.1. Abnormal glycosylation of proteins and glycosphingolipids has been shown as a mechanism behind an increased potential of tumor formation and/or progression. Human tumors overexpress ganglioside GD3 (NeuAcalpha2,8NeuAcalpha2, 3Galbeta1,4Glc-Cer), which in meningiomas correlates with deletions on chromosome 22. It is the first time that a glycosyltransferase gene is involved in tumor-specific genomic rearrangements. An abnormal function of the human like-acetylglucosaminyltransferase protein may be linked to the development/progression of meningioma by altering the composition of gangliosides and/or by effect(s) on other glycosylated molecules in tumor cells.

Mid-clavicle fractures in adults: end result study after conservative treatment.

OBJECTIVE: The aim of the present study was to analyze the long-term outcome of mid-clavicle fractures in adults and to evaluate the clinical importance of displacement and fracture comminution. DESIGN: Two hundred twenty-five mid-clavicular fractures that had been nonsurgically treated at Malmö University Hospital were retrospectively evaluated, both clinically and radiographically, an average of seventeen years after injury. There were seventy-one undisplaced fractures, sixty-nine displaced two-fragment fractures, and eighty-five displaced and comminuted fractures. The average patient age at the time of trauma was thirty-three years (range 15 to 70 years). Patients were interviewed, and careful clinical and radiological examination of their shoulders was performed. Two patients had experienced transient neuritis, and another two underwent operative treatment because of progressive neuropathy. SETTING: All 225 consecutive patients were treated primarily at the Malmö University Hospital, which serves the Malmö city population (250,000). PATIENTS/PARTICIPANTS: Since the beginning of this century, all radiographs taken at the Malmö University Hospital have been classified and filed for easy retrieval. In this retrospective study, all patients treated between 1970 and 1979 were identified, and those still living were called for follow-up examination. INTERVENTION: Of the 225 fractures reviewed, 197 fractures were originally treated with a figure-of-eight splint for an average period of three weeks without any attempt to reduce the displaced fractures; twenty-four patients were allowed immediate free shoulder mobilization. MAIN OUTCOME MEASUREMENTS: Clinical rating and healing were the main outcome measurements. RESULTS: At follow-up, 185 shoulders were asymptomatic. Thirty-nine shoulders had moderate pain and were rated as fair, and one patient was rated as poor. One hundred twenty-five of the fractures had healed normally, fifty-three were malunited with persistent fracture displacement, and seven were nonunions; nonunion was significantly more prevalent in cases with displaced fractures. Forty malunited fractures and three nonunions were rated as good. CONCLUSIONS: This review demonstrates that few patients with fractures of the mid-part of the clavicle require operative treatment.

Parathyroid hormone-related protein in patients with primary breast cancer and eucalcemia.

Parathyroid hormone-related protein (PTHrP) is a causative factor of humoral hypercalcemia in breast cancer and other malignancies. We studied circulating PTHrP levels with three different immunoassays directed against different parts of the PTHrP molecule in 48 patients with breast cancer and eucalcemia. The methods used were: (a) a RIA with antibodies directed toward the midregion (63-78); (b) an immunofluorometric assay with two antibodies against 1-34 and 38-67; and (c) an immunoradiometric assay with antibodies against 1-40 and 1-72. Although most patients had PTHrP levels indistinguishable from normal when measured by all three methods, four patients had increased serum levels in the IFMA. PTHrP was detected by immunohistochemistry in tumors from nearly all patients. One patient with elevated PTHrP in plasma measured by IFMA showed intense staining of tumor by immunohistochemistry; the tumor was histologically graded as III (severe) and was the largest of all tumors in this patient group. The IFMA can identify increased serum PTHrP in some patients with breast cancer who are not hypercalcemic. This assay may be especially useful in screening patients for this tumor during a relative early phase of the disease.

Differential expression of IGF-I and IGF-binding protein-1 and -2 in periportal and perivenous zones of rat liver.

IGF-I has important roles in regulating growth and metabolism. Circulating IGF-I is bound to specific binding proteins (IGFBP-1 to -6), with hepatocytes containing IGF-I, IGFBP-1 and -2 mRNA. Although many hepatic proteins are regionally expressed in the liver acinus, no studies have reported zonation of IGF protein expression. In this study we investigated the pattern of hepatic mRNA for the IGF proteins, vs the previously reported pepriportal gradient of phosphoenolpyruvate carboxykinase (PEPCK) expression. In situ hybridisation was used to analyse IGF-I, IGFBP-1, -2 and PEPCK mRNA in female Sprague-Dawley rats fed diets containing low (6%), normal (21%) or high (35%) protein. We report for the first time that IGFBP-1 and -2 and IGF-I are differentially expressed in the liver acinus. In the normal- and high-protein groups, levels of IGFBP-1 mRNA were higher in the perivenous region, i.e. the opposite gradient to PEPCK, with a higher gradient of IGFBP-1 expression in the high-protein group. In contrast, IGFBP-2 had a similar pattern to PEPCK, and a periportal gradient of IGF-I mRNA was also seen in the low-protein group. Using computerised image analysis, levels of IGFBP-1 and -2 mRNA were elevated 2- and 10-fold respectively, in the low- vs normal-protein groups. The level of IGF-I mRNA was reduced to 65% of normal, with circulating IGF-I levels at 30% and insulin levels 39% of normal. These results demonstrate that hepatocytes are a heterogeneous population with respect to regulation of IGF proteins, having specific expression patterns dependent on the position of the hepatocyte within the liver acinus.