Hyaluronan mediates airway hyperresponsiveness in oxidative lung injury.

Chlorine (Cl2) inhalation induces severe oxidative lung injury and airway hyperresponsiveness (AHR) that lead to asthmalike symptoms. When inhaled, Cl2 reacts with epithelial lining fluid, forming by-products that damage hyaluronan, a constituent of the extracellular matrix, causing the release of low-molecular-weight fragments (L-HA, <300 kDa), which initiate a series of proinflammatory events. Cl2 (400 ppm, 30 min) exposure to mice caused an increase of L-HA and its binding partner, inter-α-trypsin-inhibitor (IαI), in the bronchoalveolar lavage fluid. Airway resistance following methacholine challenge was increased 24 h post-Cl2 exposure. Intratracheal administration of high-molecular-weight hyaluronan (H-HA) or an antibody against IαI post-Cl2 exposure decreased AHR. Exposure of human airway smooth muscle (HASM) cells to Cl2 (100 ppm, 10 min) or incubation with Cl2-exposed H-HA (which fragments it to L-HA) increased membrane potential depolarization, intracellular Ca(2+), and RhoA activation. Inhibition of RhoA, chelation of intracellular Ca(2+), blockade of cation channels, as well as postexposure addition of H-HA, reversed membrane depolarization in HASM cells. We propose a paradigm in which oxidative lung injury generates reactive species and L-HA that activates RhoA and Ca(2+) channels of airway smooth muscle cells, increasing their contractility and thus causing AHR.

Hamster female protein. A divergent acute phase protein in male and female Syrian hamsters.

Normal adult male hamsters have low levels (10-20 micrograms) of female protein (FP) in serum which increase approximately fivefold during an acute phase response. In contrast, normal females have 50- to 100-fold higher serum levels and the acute phase reaction consists of a transient decrease in FP (approximately 50%), followed by a return to normal levels even under adverse conditions such as cortisone treatment (which by itself has a depressing effect on FP levels in normal females). The acute phase response was not inherently associated with gender, as the pattern of response could be changed to that of the opposite sex by appropriate hormonal manipulation. That is, castrated or diethylstilbestrol-treated males with high FP levels showed a female-type response whereas testosterone-treated females with low FP levels showed a male-type response. Studies on catabolism of 125I-FP showed a similar rapid half-life (T1/2, 9-16 h) in normal males and females and indicated that the sex difference in serum concentration was due to greater synthesis of FP in females. The divergent acute phase reaction of serum FP was related directly to changes in the FP synthetic rate (increased in males, decreased in females). As an indicator of serious pathology, a decrease of FP to very low levels in females was associated frequently with impending death.

Novel serum markers of fibrosis progression for the follow-up of hepatitis C virus-infected patients.

Liver biopsy is considered the gold-standard method for the assessment of liver fibrosis during follow-up of hepatitis C virus-infected patients, but this invasive procedure is not devoid of complications. The aim of the present study was to identify novel non-invasive markers of fibrosis progression. By microarray analysis, we compared transcript levels in two extreme stages of fibrosis from 16 patients. Informative transcripts were validated by real-time PCR and used for the assessment of fibrosis in 23 additional patients. Sixteen transcripts were found to be dysregulated during the fibrogenesis process. Among them, some were of great interest because their corresponding proteins could be serologically measured. Thus, the protein levels of inter-alpha inhibitor H1, serpin peptidase inhibitor clade F member 2, and transthyretin were all significantly different according to the four Metavir stages of fibrosis. In conclusion, we report here that dysregulation, at both the transcriptional and protein levels, exists during the fibrogenesis process. Our description of three novel serum markers and their potential use as serological tests for the non-invasive diagnosis of liver fibrosis open new opportunities for better follow-up of hepatitis C virus-infected patients.

Hepatic synthesis of alpha 2 (acute phase)-globulin of rat plasma.

Synthesis of plasma alpha(2) (acute phase)-globulin was demonstrated in isolated perfused rat liver obtained from animals showing acute inflammatory reaction to injury. These findings indicate that the liver is a source of the globulin and that appearance of this protein in the serum results from de novo synthesis by the liver rather than from release of performed and stored globulin.

2-D DIGE and MS/MS analysis of protein serum expression in rats housed in concrete and clay cages in winter.

In a previous study, we examined the physiological responses of male Sprague-Dawley rats over a 4-week exposure to concrete and clay cages. No general toxicological changes were observed in rats exposed to either of the two cage types in summer. Under winter conditions, however, various general toxicological effects were detected in rats housed in concrete cages, although rats housed in clay cages showed no such effects. The infrared thermographic examination indicated that skin temperature in the concrete-housed rats was abnormally low, but not so in the clay-housed rats. We examined proteomic changes in the serum of rats housed in winter in concrete and clay cages using two-dimensional differential in-gel electrophoresis and mass spectrometry/mass spectrometry. Five proteins were identified and quantitatively validated; all were cold stress-induced, acute phase proteins that were either up-regulated (haptoglobin) or down-regulated (alpha-1-inhibitor III, alpha-2u globulin, complement component 3, and vitamin D-binding protein) in the concrete-housed rats. These results suggest that the 4-week exposure to a concrete cage in winter elicited a typical systemic inflammatory reaction (i.e. acute phase response) in the exposed rats.

Superficial zone chondrocytes in normal and osteoarthritic human articular cartilages synthesize novel truncated forms of inter-alpha-trypsin inhibitor heavy chains which are attached to a chondroitin sulfate proteoglycan other than bikunin.

OBJECTIVE: We have examined the occurrence of the inflammation-associated inter-alpha-trypsin inhibitor (IalphaI) components, bikunin, heavy chain (HC)1 and HC2 in normal cartilage and osteoarthritis (OA) cartilage and synovial fluids. DESIGN/METHODS: Cartilage extracts from normal donors and late-stage OA patients, and synovial fluids from OA patients were studied by Western blot with multiple antibodies to bikunin, HC1 and HC2. Cell and matrix localization was determined by immunohistochemistry and mRNA by RT-PCR. RESULTS: Bikunin.chondroitin sulfate (CS) and IalphaI were abundant in OA cartilages, but virtually undetectable in normal. In both OA and normal cartilages, HCs were largely present in a novel C-terminally truncated 50-kDa form, with most, if not all of these being attached to CS on a proteoglycan other than bikunin. Synovial fluids from OA patients contained bikunin.CS and full-length (approximately 90 kDa) HCs linked to hyaluronan (HA) as HC.HA (SHAP.HA). Immunohistochemistry showed intracellular and cell-associated staining for bikunin and HCs, consistent with their synthesis by superficial zone chondrocytes. PCR on multiple human normal and OA cartilage samples detected transcripts for HC1 and HC2 but not for bikunin. In OA cartilages, immunostaining was predominantly matrix-associated, being most intense in regions with a pannus-like fibrotic overgrowth. CONCLUSION: The truncated structure of HCs, their attachment to a proteoglycan other than bikunin, PCR data and intracellular staining are all consistent with synthesis of HC1 and HC2 by human articular chondrocytes. The presence of bikunin.CS and IalphaI in OA cartilage, but not in normal, appears to be due to diffusional uptake and retention through fibrillated (but not deeply fissured) cartilage surfaces.

Role of serum-derived hyaluronan-associated protein-hyaluronan complex in ovarian cancer.

The objective of this study was to determine if the level of serum hyaluronan (HA), serum-derived HA-associated protein (SHAP)-HA complex, and urinary trypsin inhibitor (UTI) correlate with the clinical outcome of ovarian cancer patients. The relationship of metalloproteinase and its inhibitor with HA and the SHAP-HA complex was also examined. Serum and urine samples were obtained from 45 patients with ovarian cancer, 22 patients with benign ovarian tumors and 50 healthy women. Concentrations of serum HA and UTI were measured by an inhibitory sandwich enzyme-linked immunosorbent assay, and concentrations of the serum SHAP-HA complex were measured by a sandwich enzyme-linked immunosorbent assay. Concentrations of MMP-2, MMP-9 and TIMP-1 were measured by a one-step enzyme immunoassay. The levels of HA, SHAP-HA complex, MMP-9 and TIMP-1 were higher in the ovarian cancer group than in the benign ovarian tumor group. In ovarian cancer patients, the levels of HA, SHAP-HA complex and MMP-9 were higher in the stage III/IV group than in the stage I/II group, and the levels of SHAP-HA complex, MMP-9 and TIMP-1 were higher in the non-responder group than in the responder group. The serum concentration of SHAP-HA complex had a significant correlation with HA, MMP-9 and TIMP-1 in ovarian cancer patients. The patients with elevated SHAP-HA complex had a shorter disease-free survival compared with those with normal levels of SHAP-HA complex. The multiple regression analysis revealed that SHAP-HA complex is the significant independent variable for progression-free survival. The elevated level of SHAP-HA complex may indicate the prognosis of recurrence and reflect the tumor metastasis associated with MMP-9 in ovarian cancer patients.

Down-regulation of matriptase by overexpression of bikunin attenuates cell invasion in prostate carcinoma cells.

The precise mechanisms of metastasis in prostatic cancer are still unknown. A subculture cell line (PC-J) was isolated from the metastasis human prostate cell line PC-3. In vitro cell proliferation, wound healing and invasion assays revealed that tumorigenesis and metastasis differed between PC-3 and PC-J cells. Eight weeks after nude mice were prostate-injected with PC-J and PC-3 cells, the PC-3 group had low tumor volume and exhibited metastasis whereas the PC-J group had high tumor volume and no metastasis. Subsequent RT-PCR and immunoblot assays indicated that matriptase was the putative metastatic gene. Overexpression of bikunin significantly reduced the gene expression of matriptase, which attenuated in vitro cell invasion in the PC-3 cells. In vitro and xenograft animal models indicated different metastatic characteristics between PC-3 and PC-J cells, suggesting that matriptase plays an important role in the metastasis of prostate cancer.

Up-regulation of alpha1-microglobulin by hemoglobin and reactive oxygen species in hepatoma and blood cell lines.

alpha(1)-Microglobulin is a 26-kDa glycoprotein synthesized in the liver, secreted to the blood, and rapidly distributed to the extravascular compartment of all tissues. Recent results show that alpha(1)-microglobulin has heme-binding and heme-degrading properties and it has been suggested that the protein is involved in the defense against oxidation by heme and reactive oxygen species. In the present study the influence of hemoglobin and reactive oxygen species (ROS) on the cellular expression of alpha(1)-microglobulin was investigated. Oxy- and methemoglobin, free heme, and Fenton reaction-induced hydroxyl radicals induced a dose-dependent up-regulation of alpha(1)-microglobulin on both mRNA and protein levels in hepatoma cells and an increased secretion of alpha(1)-microglobulin. The up-regulation was reversed by the addition of catalase and ascorbate, and by reacting hemoglobin with cyanide which prevents redox reactions. Furthermore, the blood cell lines U937 and K562 expressed alpha(1)-microglobulin at low levels, and this expression increased up to 11-fold by the addition of hemoglobin. These results suggest that alpha(1)-microglobulin expression is induced by ROS, arising from redox reactions of hemoglobin or from other sources and are consistent with the hypothesis that alpha(1)-microglobulin participates in the defense against oxidation by hemoglobin, heme, and reactive oxygen species.

Free alpha-globin pool in human bone marrow.

A pool of free alpha-globin chains was found in the bone marrow samples from three controls, two patients with beta-thalassemia trait, three with sickle beta-thalassemia, three with hemoglobin (Hb) Lepore trait, one with alphabeta-thalassemia, four with homozygous beta-thalassemia, and one doubly heterozygous for Hb Lepore and beta-thalassemia. The average percentage of newly synthesized alpha-chains found in the free alpha-globin pool was 6.2% in the controls and 33.0% in the patients heterozygous for thalassemia or Hb Lepore. These controls and patients had balanced beta- and alpha-globin synthesis in the bone marrow. In the homozygous patients and in the one patient doubly heterozygous for thalassemia and Hb Lepore, there was a marked deficit of beta-chain synthesis in the bone marrow and also a large pool of newly synthesized free alpha-chains. The function of this pool of free alpha-chains is not known, but it may be involved in the regulation of globin chain synthesis in normal patients and in the compensatory synthesis of beta-chains that occurs in the bone marrow of patients heterozygous for thalassemia or for Hb Lepore.

Metabolism of thyroxine-binding globulin in man. Abnormal rate of synthesis in inherited thyroxine-binding globulin deficiency and excess.

It has been previously suggested that inherited thyroxine-binding globulin (TBG) abnormalities in man may be due to mutations at a single X-chromosome-linked locus controlling TBG synthesis. However, abnormalities in TBG degradation have not been excluded. The availability of purified human TBG and its successful labeling with radioiodide allowed us to examine such possibility. Human TBG was purified by affinity chromatography, labeled under sterile conditions with 131I or 125I,, and mixed with [125I]thyroxine (T4) or [131I]T4, respectively, before their intravenous injection. Blood and urine samples were collected over a 10-day period, and the turnover parameters were calculated. In eight normal volunteers mean values +/-SD for TBG and T4 respectively, were as follows: Half time (t1/2) 5.3 +/- 0.4 and 7.0 +/- 0.6 days; distribution space (DS) 7.2 +/- 1.0 and 10.8 +/- 1.2 liters; and total daily degradation (D) 0.211 +/- 0.053 and 0.088 +/- 0.011 mumol/day. In all subjects, t1/2 of TBG was shorter than that of T4; and the DS was smaller. 2.4 mol of TBG was degraded for each mole of T4. In five of six subjects from four families, comprising hemizygous and heterozygous carriers of TBG absence, decrease, and excess, the t1/2 and DS for TBG were within the normal range. The D of TBG was proportional to the serum concentration of the protein. Changes in the T4 kinetics in these patients were compatible with euthyroidism and with the known alterations in the extrathyroidal T4 pool associated with the changes in serum TBG concentration. A striking decrease in the t1/2 of TBG was found only in a patient with acquired diminution in TBG concentration and in patients with thyrotoxicosis or other conditions apparently unrelated to thyroid dysfunction. TBG t1/2 was 2.5 days in a patient with multiple myeloma and 3.6 days in two patients with thyrotoxicosis. Decreased TBG t1/2 was also observed in three of six patients with nonthyroidal pathology and was associated with an increase in TBG D disproportionate to their level of serum TBG. These studies indicate that changes in TBG concentration in patients with X-chromosome-linked TBG abnormalities are due to alterations in its rate of synthesis. In other conditions, abnormalities of TBG degradation and/or rate of synthesis may be found.

Comparison of in vivo translation rates and messenger RNA levels of alpha2U-globulin in rat liver and Morris hepatoma 5123D.

The synthesis of the male rat hepatic protein alpha2U-globulin has been examined in Morris hepatoma 5123D and male host liver using pulse incorporation of labeled amino acids in vivo, followed by immunoprecipitation of the newly synthesized alpha2U-globulin from the soluble protein fraction of liver and hepatoma tissue. It was found that no alpha2U-globulin synthesizes alpha2U-globulin at a normal level (0.9 to 1.0% of total hepatic protein synthesis). A variety of liver-derived cell culture lines also did not have alpha2U-globulin synthesis. The level of the specific mRNA coding for alpha2U-globulin can be quantitated using in vitro translation of polyadenylate-containing RNA in a Krebs II ascites cell-free translational system, followed by immunoprecipitation of the alpha2U-globulin synthesized in vitro. Using this technique, it was found that host liver contained alpha2U-globulin mRNA at normal levels, whereas hepatoma tissue contained no detectable mRNA coding for this protein. Thus, alpha2U-globulin synthesis is deleted in the minimal-deviation hepatoma 5123D as a consequence of the inability of that tissue to produce functional mRNA coding for alpha2U-globulin. The implications for the regulation of gene expression in malignant cells are discussed.

Synthesis of -fetoprotein by liver, yolk sac, and gastrointestinal tract of the human conceptus.

PIP: Synthesis of serum alpha fetoprotein (AFP) was studied in 16 human embryos and fetuses from 4.2-18 weeks of gestation by incubation of selected tissues in radiolabeled amino acids followed by immunoelectrophoresis of the culture fluids and radioautography. Relatively large amounts of radioactive AFP, judged by relative intensity of AFP precipitation line on radioautography, were found in each of the liver cultures of the developing yolk sac. AFP was observed in smaller amounts in almost all gastrointestinal tract cultures studied. Labeled AFP formed in kidney cultures from 1 of 9 conceptuses and in only 1 of 14 placentas cultured. None of the cultures containing lung, thymus, pancreas, skeletal muscle, amnion, chorion, or blood produced detectable amounts of AFP.^ieng

In vitro synthesis of immunoglobulins and other proteins by dysplastic and neoplastic human mammary tissues.

The synthesis of several proteins in human mammary carcinomas and in dysplastic breast tissues was studied by tissue culture and by immunofluorescence. The synthesis of immunoglobulins showed marked quantitative and qualitative variations from one specimen to another, and a preferential synthesis of immunoglobulin G and C'3 in the carcinomas with lymphocytic infiltration. Fixation of immunoglobulins G and M on the surface of neoplastic cells was noted in some carcinomas. Secretory component was detectable in some cases by immunofluorescence, but no synthesis could be found in vitro, presumably because of unfavorable culture conditions. The synthesis of lactoferrin, casein, and some serum alpha- and beta-globulins was significantly greater in noncancerous tissues than in carcinomas. Synthesis of lactoferrin was also more frequent in the well differentiated carcinomas than in the poorly differentiated carcinomas. The tissue culture technique used in this study, although in need of better adaptation to the requirements in vitro of human mammary tissues, proved to be a useful tool for investigating the synthesis of several protein components by the epithelial cells of cancerous and dysplastic tissues of the human breast. Whether a preferential synthesis of 1 class of immunoglobulins or of other proteins might influence the evolution of a mammary lesion could not be determined in this material but it should be studied further.

Alpha-fetoprotein in ontogenesis and its association with malignant tumors.

PIP: The major steps in development of ontogenesis and the role of alpha fetoprotein (AFP) synthesis are outlined. AFP is defined and its physiocochemical characteristics are described including methods of detection and identification. The liver and yolk sac of fetuses are shown as the principle sites of AFP synthesis in ontogenesis, and the dynamics of AFP in ontogenesis from the early embryonic period through midpregnancy to pregnancy termination to AFP shut-down in early postnatal period are displayed. AFP synthesis during regeneration of the liver provides the model for studying the nature of AFP production. The role of AFP in hepatocellular cancer receives a great deal of attention, focusing on the site of AFP synthesis in cancer of the liver; demonstration of AFP in blood of cases of hepatic cancer (and other diseases) by agar-gel precipitation; quantitative aspects of AFP production by liver tumors; and etiologic and pathogenic influences on AFP production by hepatomas. Clinical aspects of the diagnosis of liver cancer are reviewed. The occurrence of AFP with teratocarcinomas is remarked upon. The article's central objective was to emphasize the importance of basic research on AFP, especially the development of an accessible high-sensitivity test for use in broad epidemiological surveys. Experimental approaches to some immediate problems were formulated: 1) Is there any external factor controlling AFP synthesis and determining its intensity? 2) Is synthesis performed only by certain cell types or is AFP production inherent in any hepatocyte? 3) Is control of AFP synthesis accomplished by regulating the intensity of the process in individual cells or by involvement of a varying number of cells? And 4) is AFP synthesis in a tumor due to maintained ability of the stem tumor cell to differentiate or is it the result of dedifferentiation of the mature hepatocyte??^ieng

Expression of the human complex-forming glycoprotein HC (alpha 1-microglobulin) in Escherichia coli.

The mature form of human protein HC, or alpha 1-microglobulin, has been expressed in Escherichia coli. Protein HC is a member of the lipocalin superfamily of hydrophobic ligand-binding proteins, and carries a heterogeneous chromophore linked covalently by a reduction-resistant bond. Protein HC was first overexpressed as a C-LytA/HC fusion protein containing the C-terminal moiety of the pneumococcal lytic amidase (LytA). Recombinant C-LytA/HC was found to be an insoluble aggregate that was solubilized with 6 M guanidinium chloride and renatured by the addition of thiol reagents in the presence of L-arginine. Recombinant protein HC (rHC) was released from C-LytA/HC by trypsin digestion and purified by size-exclusion chromatography. rHC protein possesses an N-terminal amino-acid sequence identical to that of human protein HC, and a slightly lower molecular mass as determined by SDS-PAGE. Both C-LytA/HC and rHC reacted with polyclonal antibodies raised against native protein HC. A photodiode array detection system on-line with a HPLC system has allowed the identification of a chromophore associated to rHC protein displaying significant absorption in the visible region of the spectrum in resemblance to that found in the natural form of human protein HC.

Changes in transcriptional activity and matrix association of alpha 2u-globulin gene family in the rat liver during maturation and aging.

Hepatic synthesis of alpha 2u-globulin in the male rat begins at puberty (about 40 days), reaches a peak level at about 80 days, and ceases at about 750-800 days of age. The age-dependent changes in alpha 2u-globulin synthesis are correlated with both the steady-state level of the hepatic mRNA for this protein and the rate of transcription of the alpha 2u-globulin gene family. Transcriptional activation of the alpha 2u-globulin gene family at puberty and cessation of transcription at senescence correlate with the association and dissociation of this gene domain with the nuclear matrix. Unlike the alpha 2u-globulin gene, the albumin gene in the liver shows preferential association with the nuclear matrix throughout the life. From these results we conclude that the age-dependent changes in alpha 2u-globulin synthesis are due to the alteration in the rate of transcription of the alpha 2u-globulin gene, and that the association of this gene domain to the nuclear matrix is a prerequisite to its transcriptional activation.

Sexual dimorphism and growth hormone regulation of a hybrid gene in transgenic mice.

The sexually dimorphic expression of the urinary protein genes of mice (Mup genes) in the liver is mediated by the different male and female temporal patterns of circulating GH. Normal females were induced to male levels when GH was administered by injection to mimic the male GH pattern, showing that expression at the male level does not require a male sex steroid status in addition to intermittent GH. Two Mup-alpha 2u-globulin hybrid transgenes with different Mup gene promoters showed sexually dimorphic expression, and their expression in females increased to male levels upon testosterone treatment. GH-deficient (lit/lit) mice did not express these transgenes, and GH-deficient females did not respond to testosterone treatment, showing that GH was required for induction. Both normal and GH-deficient females were induced to male levels when GH was administered by injection. This is the first report of a transgene responsive to GH. A transgene consisting of a Mup promoter fused to a Herpes simplex virus thymidine kinase reporter sequence also showed sexual dimorphism, although to a lesser degree. It was expressed at the same level in normal females and GH-deficient mice of both sexes and was induced when GH-deficient mice were treated with GH. We propose that this transgene has a basal constitutive expression, possibly due to the absence of any rodent DNA downstream of the promoter. Since expression of the transgene was significantly induced by GH, the GH response is due at least in part to sequences in the promoter region.

Sex-independent synthesis of alpha 2u-globulin and its messenger ribonucleic acid in the rat preputial gland: biochemical and immunocytochemical analyses.

alpha 2u-Globulin is the principal urinary protein of the mature male rat. The major urinary source of this protein is the liver where it is synthesized and secreted by hepatocytes under hormonal regulation. High levels of alpha 2u-globulin and its messenger RNA (mRNA) are also present in the preputial gland of both male and female rats, and neither castration nor ovariectomy significantly alters the preputial concentration of this protein and its mRNA. Per unit mass of RNA and protein, the preputial gland as compared to liver contains about 3-fold higher level of alpha 2u-globulin mRNA and about 300-fold higher level of alpha 2u-globulin. Despite a 3-fold (300%) difference in the content of alpha 2u-globulin mRNA, nuclear run-off experiments show only a 30% higher rate of alpha 2u-globulin gene transcription in the preputial gland than in the liver. Immunocytochemical analyses reveal that the liver possesses two alpha 2u-globulin cell populations, one showing higher immunoreactivity than the other. In contrast, the preputial gland contains only one type of alpha 2u-globulin containing acinar cells, and a large amount of alpha 2u-globulin accumulates in the ductal lumen. From these results we conclude that the 300% higher level of alpha 2u-globulin mRNA in the preputial gland is not due to a corresponding difference in the rate of transcription of alpha 2u-globulin gene. Such a difference may represent tissue-specific regulation at a posttranscriptional level of mRNA metabolism. Furthermore, the huge difference in the alpha 2u-globulin content of the preputial gland and the liver is primarily due to the cellular and ductal accumulation of this protein in the preputial gland vs. its rapid secretion by the liver.

Regulation of a thyroid hormone-dependent protein by growth hormone: the induction of hepatic alpha 2U globulin and its messenger ribonucleic acid in adult male hypothyroid rats.

Studies in the adult male hypothyroid rat, a known GH-deficient animal, have shown hepatic alpha 2U-globulin mRNA to be dependent on thyroid hormones. To study the effects of GH on alpha 2U-globulin synthesis in the absence of thyroid hormones, adult male rats were rendered hypothyroid before hormone treatment. The relative effects of bovine GH or T3 were studied by RIA of alpha 2U-globulin in hepatic cytosol in rats 6 weeks after thyroid ablation. alpha 2U-Globulin levels in vehicle-treated controls were 1.3 +/- 0.7 micrograms (+/- SD) alpha 2U-globulin/mg protein. After 2 days, GH (200 micrograms/100 g X day) resulted in an increase to 5.7 +/- 1.0 micrograms alpha 2U-globulin/mg (P less than or equal to 0.05), and T3 50 micrograms/100 g X day) resulted in an increase to 11.5 +/- 3.6 micrograms/mg (P less than or equal to 0.01). After 7 days, GH resulted in an increase to 12.4 +/- 4.6 micrograms/mg (P less than or equal to 0.01), and T3 resulted in an increase to 28.7 +/- 8.7 micrograms/mg (P less than or equal to 0.01). After 4 months of thyroid ablation, baseline hepatic alpha 2U-globulin levels fell to 4.8 ng alpha 2U-globulin/mg protein. Hepatic alpha 2U-globulin was determined 4 and 8 h after the injection of GH (200 micrograms/100 g). In these animals with markedly diminished hepatic alpha 2U-globulin levels, significant (P less than or equal to 0.01) increases occurred 4 h (25.4 ng/mg) and 8 h (57.2 ng/mg) after GH injection. The effects of treatment with bovine GH (200 micrograms/100 g X day) for 3 days on hepatic alpha 2U-globulin synthesis in liver slices and alpha 2U-globulin poly (A)+ RNA levels were measured in rats 10 weeks after thyroid ablation. GH significantly (P less than 0.05) increased alpha 2U-globulin synthesis as a percentage of total protein synthesis (from 0.01% to 0.035%) and alpha 2U-globulin mRNA as a percentage of total mRNA (from 0.03% to 0.24%). The results show that GH rapidly and specifically stimulates hepatic alpha 2U-globulin and its mRNA activity in thyroid hormone-deficient rats.