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B cells play critical roles in the pathogenesis of lupus. To examine the influence of B cells on disease pathogenesis in a murine lupus model, New Zealand Black and New Zealand White F1 hybrid (NZB/W) mice were generated that were deficient for CD19 (CD19−/− NZB/W mice), a B cell-specific cell surface molecule that is essential for optimal B cell signal transduction. The emergence of anti-nuclear Abs was significantly delayed in CD19−/− NZB/W mice compared with wild type NZB/W mice. However, the pathologic manifestations of nephritis appeared significantly earlier, and survival was significantly reduced in CD19−/− NZB/W mice compared with wild type mice. These results demonstrate both disease-promoting and protective roles for B cells in lupus pathogenesis. Recent studies have identified a potent regulatory B cell subset (B10 cells) within the rare CD1dhiCD5+ B cell subset of the spleen that regulates acute inflammation and autoimmunity through the production of IL-10. In wild type NZB/W mice, the CD1dhiCD5+B220+ B cell subset that includes B10 cells was increased by 2.5-fold during the disease course, whereas CD19−/− NZB/W mice lacked this CD1dhiCD5+ regulatory B cell subset. However, the transfer of splenic CD1dhiCD5+ B cells from wild type NZB/W mice into CD19−/− NZB/W recipients significantly prolonged their survival. Furthermore, regulatory T cells were significantly decreased in CD19−/− NZB/W mice, but the transfer of wild type CD1dhiCD5+ B cells induced T regulatory cell expansion in CD19−/− NZB/W mice. These results demonstrate an important protective role for regulatory B10 cells in this systemic autoimmune disease.

CD19 is a B-cell transmembrane molecule that is critical for B-cell activation. CD19 serves as a scaffold protein for key signal transduction molecules including Lyn, PI3K, and Vav, by providing docking sites for these molecules via phosphorylation of CD19-Y(513), CD19-Y(482), and CD19-Y(391). We investigated the process of CD19 tyrosine phophorylation during B-cell activation using Ab specific for each of these phosphorylated tyrosines. BCR engagement induced differential tyrosine phosphorylation, as CD19-Y(513) phophorylation occurred first, and CD19-Y(482) phosphorylation was delayed and transient. Different BCR isotypes exhibited distinct patterns of CD19 phosphorylation: IgG-BCR ligation resulted in faster phosphorylation of CD19-Y(513) and more intense phosphorylation of CD19-Y(391) than IgM-BCR ligation. This affected CD19-mediated downstream pathways involving Vav, PI3K, and Akt. Additionally, the phosphorylation profile of CD19 differed distinctly according to its plasma membrane location. CD19 phosphorylated at Y(513) was almost exclusively located within lipid rafts, whereas phosphorylated Y(482) and Y(391) were found both inside and outside of the rafts. Furthermore, the phosphorylation of all three tyrosines was remarkably enhanced and prolonged following the simultaneous stimulation of BCR and CD40. Thus, variations in phosphorylation patterns may contribute to the complexity of CD19-regulated signal transduction.

Summary Background Bullous pemphigoid (BP) is a subepidermal blistering disease characterized by autoantibodies against the hemidesmosomal proteins, BP180 and BP230. NC16A, a non-collagenous stretch of the BP180 ectodomain is the primary target of pathogenic IgG antibodies. Whereas IgG anti-BP180 autoantibodies play a primary role in the pathogenesis, there is a growing number of data regarding the potential pathogenic roles of IgE class autoantibodies in BP. Objectives To examine the levels of IgG and IgE autoantibodies against BP180 and BP230, and to investigate mutual association and clinical relevance. Methods Sera obtained from 67 BP patients and 36 healthy donors were subjected to ELISA assays to measure serum IgG and IgE levels of anti-BP180 and anti-BP230 antibodies. Results IgG anti-BP180 antibodies were positive in 63 (94%) of 67 BP patients. IgG anti-BP230, IgE anti-BP180, and IgE anti-BP230 antibodies were found in 48 (72%), 20 (30%) and 45 (67%), respectively. IgG anti-BP180 levels were correlated with the affected areas. IgG anti-BP230 antibodies tended to increase in proportion to elongation of disease duration. IgE anti-BP230 levels showed a strong association with local eosinophil accumulation, while the levels were reversely related with the affected areas in BP. Conclusions IgE autoantibodies to BP180 and BP230 are detected at high frequencies in BP. IgE anti-BP230 antibodies may have a role in attracting eosinophils to the skin lesions.

金沢大学大学院医学系研究科血管分子科学, The control of the stem cell compartment in epidermis is closely linked to the regulation of keratinocyte proliferation and differentiation. β1 integrins are expressed 2-fold higher by stem cells than transit-amplifying cells. Signaling from these β1 integrins is critical for the regulation of the epidermal stem cell compartment. To clarify the functional relevance of this differential expression of β1 integrins, we established HaCaT cells with high β1integrin expression by repeated flow cytometric sorting of this population from the parental cell line. In these obtained cells expressing β1 integrins by 5-fold, MAPK activation was markedly increased. Regarding the upstream of MAPK, Gab1 phosphorylation was also higher with high β1 integrin expression, while Shc phosphorylation was not altered. In addition, enhanced phosphatidylinositol 3-kinase activation was also observed. These observations suggest that Gab1 and phosphatidylinositol 3-kinase play pivotal roles in the β1 integrin-mediated regulation of the epidermal stem cell compartment. © 2007 Elsevier Inc. All rights reserved.

金沢大学大学院医学系研究科血管分子科学, Background: Although chemokines play an important role in various inflammatory diseases, there have been few studies about the role of chemokines in alopecia areata (AA). Objectives: To determine serum levels of chemokines in patients with AA and their clinical correlations. Methods: Serum samples from 85 patients with AA, 20 patients with atopic dermatitis, 20 patients with psoriasis vulgaris and 28 normal controls were examined by the cytometric bead array assay assessing monokine induced by interferon (IFN)-γ (MIG), RANTES, interleukin-8 (IL-8), IFN-inducible protein-10, monocyte chemoattractant protein-1, macrophage inflammatory protein (MIP)-1α, MIP-1β and eotaxin levels. Secreted chemokine levels from peripheral blood mononuclear cells (PBMC) of patients with AA were also investigated. Results: Serum MIG, RANTES, IL-8 and eotaxin levels were selectively increased in patients with AA compared with normal controls. Levels of MIG, RANTES and IL-8 secreted from PBMC of patients with AA were also increased. Furthermore, elevated serum MIG and RANTES levels significantly correlated with the disease activity. RANTES levels were nonsignificantly associated with a predisposition to atopy. Conclusions: These results suggest that MIG and RANTES play an important role in the development of AA and are useful as markers of disease activity and as therapeutic targets. © 2007 The Authors.全文公開200809

金沢大学大学院医学系研究科血管分子科学, Background: B cells have been demonstrated to have critical roles in developing autoimmune bullous diseases. Recently identified tumor necrosis factor-like molecules, B cell-activating factor of the TNF family (BAFF) and a proliferation-inducing ligand (APRIL) are essential molecules for B cell development, survival, and proliferation. Although the functions of APRIL have not been fully evaluated, recent studies suggest that circulating levels of APRIL are increased in various autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis. Objectives: To determine serum APRIL levels in patients with pemphigus vulgaris (PV) and bullous pemphigoid (BP), and compare those with clinical findings and laboratory findings. Patients/Methods: Sera from 15 PV patients, 43 BP patients, and 15 normal controls were subjected to ELISA assays to measure serum APRIL, BAFF, Dsg3, and BP180 levels. Results and conclusions: Circulating APRIL levels were significantly elevated in BP patients but not in PV patients, and correlated with serum BAFF levels. Our study revealed that serum APRIL levels tended to be increased in the quite early stage of disease. In conclusion, circulating APRIL levels may be a useful marker for early activation of autoimmune diathesis, and furthermore, an effective therapeutic target molecule in patients with BP. © 2007 Japanese Society for Investigative Dermatology.

Background: Autoimmune bullous diseases are characterized by autoantibodies against specific adhesion molecules of the skin and/or mucous membrane. While these autoantibodies are known to play a primary role in the disease manifestation, it remains unknown how disease-specific autoreactive B cells and autoantibodies are induced. Recent studies have indicated the importance of the CD40 and CD40 ligand (CD40L) receptor-ligand pair in the immunopathogenesis of autoimmune diseases. CD40L circulates in soluble form, and some reports suggest that serum soluble CD40L (sCD40L) levels are increased in various autoimmune diseases. Objectives: To determine serum sCD40L levels in patients with pemphigus vulgaris (PV) and bullous pemphigoid (BP), and to determine their correlation with clinical findings and laboratory findings. Patients and Methods: Sera from 10 PV patients, 35 BP patients and 12 normal controls were subjected to ELISA assays to measure serum levels of sCD40L, anti-desmoglein-3 antibody and anti-BP180 antibody. Results and Conclusions: Circulating sCD40L levels were significantly elevated in BP patients, but not in PV patients. Serum sCD40L levels increased in the early stage of disease onset and recurrence in BP patients. In conclusion, circulating sCD40L levels may be a useful marker for early activation of autoimmune diathesis and, furthermore, an effective therapeutic target in patients with BP.

Although anti-Fcgamma receptor antibodies (Abs) are detected in various autoimmune diseases, there have been no studies about the anti-Fcgamma receptor Abs in alopecia areata (AA). To detect the anti-Fcgamma receptor Abs in patients with AA and their clinical correlations, Serum samples from 72 patients with AA and 23 normal controls were examined by enzyme-linked immunosorbent assay assessing anti-Fcgamma receptor Ab levels. Anti-Fcgamma receptor I Abs were significantly frequently detected in patients with AA compared with normal controls. Furthermore, the detection of anti-Fcgamma receptor I Abs significantly inversely correlated with the disease duration. These results suggest that anti-Fcgamma receptor I Ab and Fcgamma receptor I play an important role in the regulation of AA, are useful for a marker of the disease prognosis and are worth intense research for the reasonable and specific therapy of AA.

Necrolytic migratory erythema (NME) is an uncommon inflammatory dermatosis with a distinctive clinical and histological appearance. It shows irregular erythema, bullae, erosion, crusts and pigmentation. While it is typically associated with glucagonoma, some cases of NME without glucagonoma have been reported. Herein, we report a case of necrolytic migratory erythema associated with malabsorption 30 years after ileocolectomy. She presented erosive erythema with scale or partly flaccid bullae on her intergluteal cleft, buttock and extremities. Her laboratory data revealed essential amino acid deficiency and a slightly decreased serum zinc level, while her plasma glucagon level was low. With diagnosis of non-glucagonoma-associated NME with malabsorption due to short-bowel syndrome, she was treated and improved by i.v. amino acid supplement. Histological findings of NME include necrotic changes of keratinocytes in the upper epidermis, proliferation of those in the lower epidermis and inflammatory cell infiltration of upper dermis. We also examined the expression pattern of epidermal keratins (K6, K10) and Ki-67, one of the markers of proliferative activity, to assess the proliferation and differentiation of keratinocytes in a NME lesion by immunostaining. The findings with these immunostainings support the characteristics of HE-staining, and suggest hyponutrition may induce changing differentiation/proliferation of keratinocytes.

Summary Background BAFF [B-cell activating factor belonging to the tumour necrosis factor (TNF) family] is a member of the TNF superfamily that regulates B-lymphocyte proliferation and survival. It has been demonstrated that increased levels of soluble BAFF are associated with systemic autoimmunity in patients with systemic lupus erythematosus, rheumatoid arthritis and Sjogren's syndrome, and in animal models of spontaneous autoimmune diseases. However, the significance of circulating BAFF in autoimmune bullous diseases is unknown. Objectives To examine whether BAFF levels are elevated in the autoimmune blistering diseases pemphigus vulgaris (PV) and bullous pemphigoid (BP). Methods We examined sera obtained from 21 patients with PV, 39 patients with BP and 22 healthy donors. We performed enzyme-linked immunosorbent assays for soluble BAFF and each disease-specific antibody: antidesmoglein-3 antibody for PV and anti-BP180 antibody for BP. Results Significant elevations of serum BAFF levels were found in the patients with BP, but not with PV. There was apparently no significant association between the serum BAFF levels and titres of anti-BP180 antibodies in the patients with BP. However, serum BAFF levels tended to be more elevated in patients with a shorter disease duration. There was a tendency that BAFF levels increased before the anti-BP180 antibody levels increased at the onset of BP and quickly decreased in response to treatment. Conclusions BAFF may be a useful marker for early activation of an autoimmune diathesis and may play a critical role in triggering activation of self-antigen-driven autoreactive B cells in BP.

Cell surface molecules on lymphocytes positively or negatively modulate the Ag receptor signaling, and thus regulate the fate of the cell. CD22 is a B cell-specific cell surface protein that contains multiple ITIMs in the cytoplasmic tail, and critically regulates B cell activation and survival. CD22 regulation on B cell signaling is complex because CD22 can have both positive and negative roles in various contexts. We generated phosphospecific polyclonal Abs reacting four major CD22 tyrosine motifs (Y762, Y807, Y822, and Y842) and analyzed the pattern and intensity of phosphorylation of these tyrosine residues. The tyrosine motifs, Y762, Y822, and Y842, are considered as ITIM, whereas the other, Y807, is suggested to be important for Grb2 recruitment. Approximately 10% of the four tyrosine residues were constitutively phosphorylated. Upon anti-IgM ligation, CD22 Y762 underwent most rapid phosphorylation, whereas all four tyrosine residues were eventually phosphorylated equally at ∼35% of all CD22 molecules in the cell. By contrast, anti-CD40 stimulation specifically up-regulated anti-IgM-induced phosphorylation of tyrosines within two ITIM motifs, Y762 and Y842, which was consistent with in vivo finding of the negative role of CD22 in CD40 signaling. Thus, CD22 phosphorylation is not only quantitatively but also qualitatively regulated by different stimulations, which may determine the outcome of B cell signaling.

Drug-induced hypersensitivity syndrome (DIHS) is a rare but severe disease with multiorgan failure. Recently, the association of the human herpesvirus (HHV) family, particularly of HHV-6, with DIHS has been reported. We report a 43-year-old female diagnosed as having DIHS based on the clinical course and laboratory examinations. The HHV-6 reactivation was demonstrated by significantly increased levels of the specific antibody in her paired sera and by polymerase chain reaction of HHV-6 DNA. Notably, transient hypogammaglobulinaemia was detected in the early stage of the disease, which was associated with the disease activity. By contrast, the serum IgE level and eosinophils were increased 2 or 3 weeks later. In addition, serum levels of interferon γ, interleukin (IL)-4 and soluble IL-2 receptor, which were increased in the early phase of the disease, decreased gradually after the corticosteroid therapy.

The complex and coordinated regulation of flowering has high ecological and agricultural significance. The maturity locus E1 has a large impact on flowering time in soybean, but the molecular basis for the E1 locus is largely unknown. Through positional cloning, we delimited the E1 locus to a 17.4-kb region containing an intron-free gene ( E1 ). The E1 protein contains a putative bipartite nuclear localization signal and a region distantly related to B3 domain. In the recessive allele, a nonsynonymous substitution occurred in the putative nuclear localization signal, leading to the loss of localization specificity of the E1 protein and earlier flowering. The early-flowering phenotype was consistently observed in three ethylmethanesulfonate-induced mutants and two natural mutations that harbored a premature stop codon or a deletion of the entire E1 gene. E1 expression was significantly suppressed under short-day conditions and showed a bimodal diurnal pattern under long-day conditions, suggesting its response to photoperiod and its dominant effect induced by long day length. When a functional E1 gene was transformed into the early-flowering cultivar Kariyutaka with low E1 expression, transgenic plants carrying exogenous E1 displayed late flowering. Furthermore, the transcript abundance of E1 was negatively correlated with that of GmFT2a and GmFT5a , homologues of FLOWERING LOCUS T that promote flowering. These findings demonstrated the key role of E1 in repressing flowering and delaying maturity in soybean. The molecular identification of the maturity locus E1 will contribute to our understanding of the molecular mechanisms by which a short-day plant regulates flowering time and maturity.

We report a patient with herpetiform pemphigus who was negative for autoantibodies to desmoglein (Dsg)1 or 3. He had erythemas with vesicles lining the margins on the trunk and extremities. Histopathology revealed intraepidermal blister with prominent eosinophil infiltration. Direct and indirect immunofluorescence demonstrated the presence of depositing and circulating immunoglobulin (Ig)G autoantibodies, but no IgA antibodies, to keratinocyte cell surface. Nonetheless, neither anti-Dsg1 nor Dsg3 antibodies were detected by enzyme-linked immunosorbent assay. Immunoblotting using human epidermal extracts also showed no reactivity with known intraepidermal or epidermal-dermal junctional substances. Immunoelectronmicroscopy revealed the reactivity on the portion of keratinocyte cell surface but not on the desmosomes. This case suggests that non-desmoglein antigen on keratinocyte cell surface can be targeted in some patients with this unusual variant of pemphigus.

Delineating the relative contributions of B lymphocytes during the course of autoimmune disease has been difficult. Therefore, the effects of depleting all mature B cells using a potent CD20 mAb, or of depleting circulating and marginal zone B cells using a ligand-blocking CD22 mAb, were compared in NZB/W F1 mice, a model for human systemic lupus erythematosus. Single low-dose mAb treatments depleted B cells efficiently in both NZB/W F1 and C57BL/6 mice. Prophylactic B cell depletion by repeated CD20 mAb treatments prolonged survival during pristane-accelerated lupus in NZB/W F1 mice, whereas CD22 mAb had little effect. Despite effective B cell depletion, neither mAb treatment prevented autoantibody generation. In addition, CD20, CD22, and control mAb-treated NZB/W F1 mice developed anti-mouse IgG autoantibodies in contrast to parental NZB and NZW strains, which may have reduced the effectiveness of B cell depletion. Despite this, low-dose CD20 mAb treatment initiated in 12–28-wk-old mice, and administered every 4 wk thereafter, significantly delayed spontaneous disease in NZB/W F1 mice. By contrast, B cell depletion initiated in 4-wk-old mice hastened disease onset, which paralleled depletion of the IL-10–producing regulatory B cell subset called B10 cells. B10 cells were phenotypically similar in NZB/W F1 and C57BL/6 mice, but were expanded significantly in young NZB/W F1 mice. Thus, B cell depletion had significant effects on NZB/W F1 mouse survival that were dependent on the timing of treatment initiation. Therefore, distinct B cell populations can have opposing protective and pathogenic roles during lupus progression.

Although contact hypersensitivity (CHS) has been considered a prototype of T cell-mediated immune reactions, recently a significant contribution of regulatory B cell subsets in the suppression of CHS has been demonstrated. CD22, one of the sialic acid-binding immunoglobulin-like lectins, is a B cell-specific molecule that negatively regulates BCR signaling. To clarify the roles of B cells in CHS, CHS in CD22−/− mice was investigated. CD22−/− mice showed delayed recovery from CHS reactions compared with that of wild-type mice. Transfer of wild-type peritoneal B-1a cells reversed the prolonged CHS reaction seen in CD22−/− mice, and this was blocked by the simultaneous injection with IL-10 receptor Ab. Although CD22−/− peritoneal B-1a cells were capable of producing IL-10 at wild-type levels, i.p. injection of differentially labeled wild-type/CD22−/− B cells demonstrated that a smaller number of CD22−/− B cells resided in lymphoid organs 5 d after CHS elicitation, suggesting a defect in survival or retention in activated CD22−/− peritoneal B-1 cells. Thus, our study reveals a regulatory role for peritoneal B-1a cells in CHS. Two distinct regulatory B cell subsets cooperatively inhibit CHS responses. Although splenic CD1dhiCD5+ B cells have a crucial role in suppressing the acute exacerbating phase of CHS, peritoneal B-1a cells are likely to suppress the late remission phase as “regulatory B cells.” CD22 deficiency results in disturbed CHS remission by impaired retention or survival of peritoneal B-1a cells that migrate into lymphoid organs.

Prominent eosinophil infiltration is a characteristic of some forms of vasculitis, such as Churg-Strauss syndrome, also known as allergic granulomatous vasculitis. In the current study, we established a mouse model of cutaneous eosinophilic vasculitis by the cutaneous reverse passive Arthus reaction using IgE injection instead of IgG. Wild-type C57BL/6 mice were injected with IgE anti-trinitrophenyl antibodies, followed immediately by intravenous administration of trinitrophenyl bovine serum albumin. IgE-mediated immune complex challenge induced substantial hemorrhage with marked infiltration of eosinophils in which neutrophils, mast cells, and macrophages were also mixed. This finding contrasted remarkably with the neutrophil-dominant infiltration pattern in IgG-mediated immune complex challenge. In the lesion, the expression level of monocyte chemotactic protein-3 was increased, and anti-monocyte chemotactic protein-3 treatment resulted in a significant but incomplete blockade of eosinophil recruitment. Furthermore, mice lacking E-selectin, P-selectin, L-selectin, or intercellular adhesion molecule-1, as well as wild-type mice that received anti-vascular cell adhesion molecule-1-blocking antibodies were assessed for the IgE-mediated Arthus reaction. After 24 hours, the loss of P-selectin resulted in a significant reduction in eosinophil accumulation compared with both wild-type mice and other mouse mutants. Collectively, the Fc class of immunoglobulins, which forms these immune complexes, critically determines the disease manifestation of vasculitis. The IgE-mediated cutaneous reverse passive Arthus reaction may serve as an experimental model for cutaneous eosinophilic infiltration in vasculitis as well as in other diseases.

New ring transformations of 3,5-dinitro-1-(4-nitrophenyl)-4-pyridone and its homologues with hydroxylamine were found to give 4-nitro-5(2H)-isoxazolone. These results were rationalized by double ring transformations in sequence. The fact that the 4-position of the 4-pyridone behaved as an electrophlic site was the first example in this series of ring transfomations, and was caused by the alpha-effect of the reagent. Some reactions of the isoxazolone were carried out.

Contact hypersensitivity (CHS) is a cutaneous immune reaction mediated mainly by antigen-specific effector T cells and is regarded as a model for Th1/Tc1-mediated inflammation. However, recent reports have suggested pivotal roles of B cells in CHS. CD19 serves as a positive B-cell response regulator that defines signaling thresholds critical for B-cell responses. In the current study, we assessed the role of the B-cell-specific surface molecule CD19 on the development of CHS by examining CD19-deficient mice. Although CD19-deficient mice are hyposensitive to a variety of transmembrane signals, CD19 loss resulted in increased and prolonged reaction of CHS, suggesting an inhibitory role of CD19 expression in CHS. Sensitized lymph nodes and elicited ear lesions from CD19-deficient mice exhibited Th1/Tc1-shifted cytokine profile with increased interferon-gamma expression and decreased interleukin-10 expression. Adoptive transfer experiments revealed that CD19 expression in recipient mice was required for optimal suppression of CHS response, indicating its role in the elicitation phase. Furthermore, spleen B cells, especially marginal zone B cells, from wild-type mice were able to normalize exaggerated CHS reactions in CD19-deficient mice. Thus, CD19 expression in B cells is critical for termination of CHS responses, possibly through the function of regulatory B cells.

We report the case of a 55-year-old female with bullous pemphigoid (BP) who was positive for anti-BP180 and anti-laminin 5 antibodies after development of graft-vs-host disease (GVHD) caused by a bone marrow transplant. She had tense blisters on her trunk and extremities. Histologic examination showed a subepidermal blister and marked lymphocytic infiltration, especially eosinophils. Direct immunofluorescence revealed a linear deposition of IgG on the base membrane zone. Indirect immunofluorescence on 1M NaCl split skin revealed a linear IgG deposition to both sides of the epidermal and the dermal layers. Immunoblot assays using human epidermal extracts and BP180 NC16a domain recombinant protein confirmed the presence of IgG antibodies against BP180 and recombinant BP180 NC16a domain protein. Furthermore, immunoblotting using laminin 5 purified from human keratinocyte extract as the substrate demonstrated reactivity against the gamma2 and beta3 subunits but not the alpha3 subunit of laminin 5. We diagnosed BP and treated her with prednisolone (40 mg/day). Both skin and oral lesions resolved without leaving scars on the bulla. Immune disturbance as well as destruction of basal epidermal cells and base membrane by GVHD may result in the induction of autoimmune blistering diseases with unusual clinical and laboratory manifestations.

The inner structure of uniform spherical nickel phosphate particles was examined. The particles were agglomerates of the fine primary particles with a high mesoporosity and showed a fairly high selective adsorption of H2O when treated below 100°C in vacuo.

Using tumour cell lines derived from human bone tumours, specific binding sites for epidermal growth factor (EGF), a potent growth stimulator in many tissues, and its effect on synthesis of prostaglandin (PG) E2, a potent bone-resorbing factor, by cultured osteosarcoma cell line were studied. Three tumour cell lines, one osteosarcoma (HOSO) and two giant cell tumours of the bone (G-1 and G-2), all possessed specific binding sites for 125I-labelled EGF: the apparent dissociation constant was ~4–10 × 10−10 m and the maximal binding capacity was 50 000–80 000 sites/cell. EGF had no mitogenic effect in these cell lines. However, these cell lines did not have specific binding sites for 125I-labelled parathyroid hormone (PTH) or calcitonin. HOSO line produced and secreted PGE2 into medium, while no significant amount of PGE2 was demonstrated in G-1 or G-2 line. EGF significantly stimulated PGE2 production in HOSO line in a dose-dependent manner (0.5–50 ng/ml); its stimulatory effect was completely abolished by indomethacin, an inhibitor of PG biosynthesis. Exogenous PGE1 significantly stimulated cyclic AMP formation in HOSO line, whereas PGF2α, PTH, calcitonin, or EGF had no effect. None of these calcium-regulating hormones affected cyclic AMP generation in either G-1 or G-2 line. These data indicate that human bone tumour cells have specific EGF receptors unrelated to cell growth, and suggest that EGF may be involved in bone resorption through a PGE2-mediated process in human osseous tissues.

The effects of bromocriptine, a dopamine agonist, and cyproheptadine, a serotonin antagonist, on basal and corticotropin-releasing factor (CRF)-stimulated ACTH release were investigated in a 40-year-old female patient with Nelson's syndrome. Oral administration of either bromocriptine (2.5 mg) or cyproheptadine (8 mg) caused a marked drop in plasma ACTH levels. Intravenous administration of synthetic ovine (o) CRF (50 micrograms) produced an exaggerated response of plasma ACTH. Short-term (3-week) treatment with either bromocriptine (7.5 mg/day) or cyproheptadine (12 mg/day) resulted in a marked suppression of basal ACTH release. Furthermore, a blunted response of plasma ACTH to oCRF was observed after short-treatment with either drug. However, after a longer period of treatment with cyproheptadine (18-week), plasma ACTH levels rose again and hyperresponsiveness to oCRF was restored to the pretreatment levels. These data indicate that synthetic oCRF is a potent secretagogue for ACTH release in a patient with Nelson's syndrome. It is suggested that bromocriptine and cyproheptadine are effective drugs in reducing basal and CRF-stimulated ACTH release, possibly acting at the pituitary level in this case. However, the apparent refractoriness after chronic treatment with cyproheptadine may limit its therapeutic use in the present case.

Release of immunoreactive ACTH and β-endorphin (β-EP) in response to corticotrophin-releasing factor (CRF) and dopaminergic agents was studied in vivo and in vitro in a patient with Cushing's disease. Iv administration of synthetic ovine (o) CRF significantly stimulated plasma ACTH release, accompanied by increase of plasma cortisol levels. Oral administration of bromocriptine significantly suppressed plasma cortisol levels. Although reduced responses of plasma ACTH and cortisol to o-CRF was observed 1 month after removal of the pituitary adenoma, these normalized 6 months after operation. In vitro perifusion of the pituitary adenoma obtained by surgery revealed that o-CRF also stimulated ACTH and β-EP release in a dose-responsive manner (10−9m–10−5 m) and that dopamine suppressed their basal secretion. Gel exclusion chromatography of the perfusates showed that the predominant component of ACTH and β-EP before and after o-CRF stimulation coeluted with standard ACTH and β-EP, respectively. The present data suggest that o-CRF is a potent secretagogue for ACTH and β-EP release from the human pituitary adenoma causing Cushing's disease and that ACTH secretion from certain adenomas, possibly originating from the intermediate lobe of the pituitary gland, is partly regulated by a dopaminergic mechanism.