Hypothyroidism caused by phenobarbital affects patterns of estrous cyclicity in rats.

We found that repeated treatment with phenobarbital (PB), a thyroid modulator, resulted in a persistent estrous stage in the present study. Although the effects of PB in blocking the surge release of luteinizing hormone (LH), inducing anovulation and prolonging the diestrous period has been well established, there is still no research describing the appearance of persistent estrous states in normal cycling rats dosed with PB. To further study this phenomenon, female rats exhibiting regular estrous cycle were administered an oral dose of PB for 14 consecutive days. Consecutively, vaginal smears were observed and rats from all the groups were sacrificed and serum hormone levels for prolactin, progesterone, estradiol, triiodothyronin (T3), thyroxine (T4) and thyroid stimulating hormone (TSH) were measured. Pituitary, thyroid, liver, uteri and ovaries were excised, weighed and further subjected to histological observations. We found that PB induced irregular estrous cycles, especially persistent estrus in rats. Histopathologically, the persistent estrous stages are characterized by persistent vaginal cornification in the vagina, cystic follicles and anovulation in the ovaries. Endocrinologically, serum T3 and T4 levels were significantly lower, and TSH was higher in treated-female rats compared to control females. The serum estradiol level and the estradiol/progesterone ratio tend to increase in treated-females. Furthermore, PB-treated animals with irregular estrous cycle were reduced by T4 replacement. Our data indicate that treatment with PB resulted in hypothyroidism and irregular estrous cycle, particularly a persistent estrous stage in normal cycling female rats.

Discovery, optimization, and pharmacological characterization of novel heteroaroylphenylureas antagonists of C-C chemokine ligand 2 function.

Through the application of TRAP (target-related affinity profiling), we identified a novel class of heteroaroylphenylureas that inhibit human CCL2-induced chemotaxis of monocytes/macrophages both in vitro and in vivo. This inhibition was concentration-dependent and selective with regard to other chemokines. The compounds, however, did not antagonize the binding of (125)I-labeled CCL2 to the CCR2 receptor nor did they block CCR2-mediated signal transduction responses such as calcium mobilization. Optimization of early leads for potency and pharmacokinetic parameters resulted in the identification of 17, a potent inhibitor of chemotaxis (IC(50) = 80 nM) with excellent oral bioavailability in rats (F = 60%). Compound 17 reduced swelling and joint destruction in two rat models of rheumatoid arthritis and delayed disease onset and produced near complete resolution of symptoms in a mouse model of multiple sclerosis.

Kallidinogenase normalizes retinal vasopermeability in streptozotocin-induced diabetic rats: potential roles of vascular endothelial growth factor and nitric oxide.

We studied the suppressant effect of kallidinogenase on retinal vascular permeability and vascular endothelial growth factor (VEGF) in diabetic rats. Diabetes was induced by intravenously injecting streptozotocin (60 mg/kg body weight) dissolved in citrate buffer. Kallidinogenase (7 microg/kg/day) was injected intravenously once daily for 21 days. The retinal vascular permeability was estimated from the amount of fluorescent dye leaking into the retina after administration of fluorescein isothiocyanate-conjugated dextran. VEGF in intraocular fluids was quantified by an enzyme-linked immunosorbent assay. The amounts of nitrite and nitrate in the retina were quantified by a fluorescence method using 2,3-diaminonaphthalene. Retinal vascular permeability in the diabetic control group was about 5.5 times higher than in the normal control group (P<0.001). Kallidinogenase suppressed the increased retinal vascular permeability. In the diabetic control group, the VEGF level was three times that of the normal control group (diabetic control group, 160+/-12 pg/ml; normal control group, 54+/-9 pg/ml; P<0.001). The VEGF concentration in the kallidinogenase-treated group was 120+/-12 pg/ml (P<0.05). In the diabetic control group, the amounts of nitrite and nitrate in the retina were lower by about 2.6-fold, compared with the normal control group (P<0.05). Kallidinogenase almost normalized the decreases in nitrite and nitrate in the retina. The current study showed beneficial effects of kallidinogenase on increased retinal vascular permeability and VEGF in diabetic rats, suggesting that kallidinogenase may be effective for simple retinopathy in patients with diabetes.

Design, synthesis, and structure-activity relationships of novel insulin receptor tyrosine kinase activators.

A novel series of symmetrical ureas of [(7-amino(2-naphthyl))sulfonyl]phenylamines were designed, synthesized, and tested for their ability to increase glucose transport in mouse 3T3-L1 adipocytes, a surrogate readout for activation of the insulin receptor (IR) tyrosine kinase (IRTK). A structure-activity relationship was established that indicated glucose transport activity was dependent on the presence of two acidic functionalities, two sulfonamide linkages, and a central urea or 2-imidazolidinone core. Compound 30 was identified as a potent and selective IRTK activator. At low concentrations, 30 was able to increase the tyrosine phosphorylation of the IR stimulated by submaximal insulin. At higher concentrations, 30 was able to increase tyrosine the phosphorylation levels of the IR in the absence of insulin. When administered intraperitoneally (ip) and orally (po), 30 improved glucose tolerance in hypoinsulinemic, streptozotocin-treated rats. These data provide pharmacological validation that small molecule IRTK activators represent a potential new class of antidiabetic agents.

SKL-2841, a dual antagonist of MCP-1 and MIP-1 beta, prevents bleomycin-induced skin sclerosis in mice.

Systemic sclerosis (SSc) is a connective tissue disease characterized by fibrosis and excessive collagen deposition in the skin and various internal organs. In early stages of SSc, the dermis reveals infiltration of inflammatory cells associated with increased collagen synthesis. SKL-2841 was initially synthesized as a novel small molecule antagonist of MCP-1. In this study, we indicated that SKL-2841 also exerts anti-chemotactic activity for MIP-1 beta in mouse spleen cells. In the early stages of bleomycin-induced skin lesions, immunohistochemical analysis showed the expression of both MCP-1 and MIP-1 beta in dermal inflammatory cells. Moreover, intraperitoneal administration of SKL-2841 suppressed the infiltration of inflammatory mononuclear cells and polymorphonuclear cells in the acute phase and also significantly suppressed fibrillization in the chronic phase in bleomycin-induced scleroderma, compared with PBS treatment. These findings suggest that SKL-2841 has potential as a compound for the treatment of conditions associated with skin fibrosis such as SSc.