The complete sequence of the rice (Oryza sativa L.) mitochondrial genome: frequent DNA sequence acquisition and loss during the evolution of flowering plants.

The entire mitochondrial genome of rice (Oryza sativa L.), a monocot plant, has been sequenced. It was found to comprise 490,520 bp, with an average G+C content of 43.8%. Three rRNA genes, 17 tRNA genes and five pseudo tRNA sequences were identified. In addition, eleven ribosomal protein genes and two pseudo ribosomal protein genes were found, which are homologous to 13 of the 16 genes for ribosomal proteins in the mitochondrial genome of the liverwort (Marchantia polymorpha). A greater degree of variation in terms of presence/absence and integrity of genes was observed among the ribosomal protein genes and tRNA genes of rice, Arabidopsis and sugar beet. Transcription and post-transcriptional modification (RNA editing) in the rice mitochondrial sequence were also examined. In all, 491 Cs in the genomic DNA were converted to Ts in cDNA. The frequency of RNA editing differed markedly depending upon the ORF considered. Sequences derived from plastid and nuclear genomes make up 6.3% and 13.4% of the mitochondrial genome, respectively. The degree of conservation of plastid sequences in the mitochondrial genome ranged from 61% to 100%, suggesting that sequence migration has occurred very frequently. Three plastid DNA fragments that were incorporated into the mitochondrial genome were subsequently transferred to the nuclear genome. Nineteen fragments that were similar to transposon or retrotransposon sequences, but different from those found in the mitochondrial genomes of dicots, were identified. The results indicate frequent and independent DNA sequence flow to and from the mitochondrial genome during the evolution of flowering plants, and this may account for the range of genetic variation observed between the mitochondrial genomes of higher plants.

Expression of arginine vasopressin and vasopressin V1a receptor mRNA in diabetic (db/db) mice.

To assess the involvement of arginine vasopressin (AVP) in genetical diabetic (db/db) mice, we examined the mRNA expression levels of AVP and vasopressin V(1a) receptors (V(1a)R) in brain and liver of db/db mice. In 10 week-old db/db mice, a significant elevation in blood sugar levels and plasma osmolality were observed, showing obvious diabetic symptoms. There was a significant increase in brain AVP mRNA levels in db/db mice. The expression level of liver V(1a)R mRNA in db/db mice was significantly down-regulated, presumably as a consequence of ligand-receptor interaction. This is in contrast to results that show no significant reduction in brain V(1a)R mRNA levels when comparing db/db and control mice. Thus, it is possible that in the progress of genetic diabetes mellitus, AVP acts in liver than in brain through V(1a)R.

Silent stroke: pathogenesis, genetic factors and clinical implications as a risk factor.

Silent stroke is frequently recognized in elderly persons. Diffusion-weighted magnetic resonance imaging has proved to be highly sensitive in the detection of recent silent stroke, and may further applications in the future. Silent stroke in healthy and asymptomatic individuals mainly comprises lacunar infarcts, which are often associated with white matter changes. Thus, analyses of risk factors and genetic factors in small-vessel diseases such as lacunar infarct and white matter changes may provide clues regarding the pathogenesis of silent stroke. Silent stroke may be a risk factor for clinical stroke and cognitive impairment, but prospective studies are required to confirm this.

Mechanism of AVP release and synthesis in chronic salt-loaded rats.

Arginine vasopressin (AVP) is involved in osmotic regulation in the brain and peripheral tissues. To elucidate the regulatory mechanism that involves AVP release in hyperosmolality, we investigated the regulation of the synthesis and release of AVP in chronic salt-loaded rats. In chronic salt-loaded rats, which were generated by free access to water containing 2% NaCl for 7 days, plasma osmolality was significantly increased compared with control value. When tested, the AVP content was significantly higher in plasma but lower in the pituitary and whole brain (hypothalamus, cortex and striatum) than in control rats. The expression of AVP mRNA in the brain was significantly up-regulated compared with that in control rats. These data lead to the suggestion that hyperosmolality stimulates AVP release from the brain and subsequently induces AVP synthesis in the brain. On the other hand, mRNA levels of vasopressin V1a receptor (V1aR), whose down-regulation is known to be a counteraction to the V1aR activation, was not changed in the brain, suggesting that the AVP seems not to interact with the V1aR in the brain. These results suggest that hyperosmosis promotes the release of AVP into plasma, the subsequent induction of AVP mRNA in the brain and its action on the peripheral tissues.

Alteration in expression profiles of a series of diabetes-related genes in db/db mice following treatment with thiazolidinediones.

We studied the effect of pioglitazone on the transcription of 42 genes associated with diabetes to examine the relationship between the antidiabetic action of thiazolidinediones (TZDs) and their ability to modulate transcription through their peroxisome proliferater-activated receptor (PPAR)-agonistic activity. Diabetic (db/db) mice were orally administered with pioglitazone for two weeks. Total RNA was prepared from liver, muscle and adipocytes and the quantity of mRNA was determined by comparative RT-PCR. The expression of diabetes-related genes was compared between lean and untreated db/db mice and between untreated and drug-treated db/db mice. The onset of diabetes was associated with a considerable alteration in the expression of a large number of diabetes-related genes. Treatment of db/db mice with pioglitazone modulated the expression of genes involved in the metabolism of glucose, lipids and lipoproteins. This included genes for phosphoenolpyruvate carboxykinase, beta-oxidation enzymes, lipoprotein lipase, apolipoprotein AI and uncoupling proteins. Most of the genes responsible for insulin signaling were unaffected. Administration of pioglitazone was also shown to induce PPARgamma expression in liver and muscle. It is therefore possible to hypothesize that TZDs may ameliorate diabetes through a mechanism of action involving a direct decrease in plasma glucose and triglyceride levels and improvements in free fatty acid-induced insulin resistance.

Nonpeptide mimic of bradykinin with long-acting properties.

Kinins, members of a family of peptides released from kininogens by the action of kallikreins, have been implicated in a variety of biological activities including vasodilation, increased vascular permeability, contraction of smooth muscle cells and activation of sensory neurons. However, investigation of the physiological actions of kinins have been greatly hampered because its effects are curtailed by rapid proteolytic degradation. We examined the pharmacological characteristics of the first nonpeptide bradykinin receptor agonist 8-[2,6-dichloro-3-[N-[(E)-4-(N-methylcarbamoyl)cinnamidoacetyl+ ++]-N-methylamino]benzyloxy]-2-methyl-4-(2-pyridylmethoxy)quinolin e (FR190997). FR190997, whose structure is quite different from the natural peptide ligand, but is similar to the nonpeptide antagonists FR165649, FR167344 and FR173657, potently and selectively interacts with the human B2 receptor and markedly stimulates inositol phosphate formation in transfected Chinese hamster ovary (CHO) cells. FR190997 induces concentration-dependent contraction of isolated guinea pig ileum. In vivo, FR190997 mimics the biological action of bradykinin and induces hypotensive responses in rats with prolonged duration, presumably as a consequence of its resistance to proteolytic degradation. Therefore, FR190997 is a highly potent and subtype-selective nonpeptide agonist which displays high intrinsic activity at the bradykinin B2 receptor. This compound represents a powerful tool for further investigation of the physiology and pathophysiology of bradykinin receptors.

Evaluation of genetic risk factors for silent brain infarction.

BACKGROUND AND PURPOSE: Silent brain infarction (SBI) is often found with white matter hyperintensity. A recent genetic study on elderly twins indicated that the susceptibility to white matter hyperintensity was largely determined by genetic factors, implying the existence of genetic susceptibility for SBI as well. We therefore studied 3 genetic polymorphisms in SBI, the deletion/insertion polymorphism of angiotensin-converting enzyme (ACE) gene, the apolipoprotein(a) [apo(a)] size polymorphism, and the T677C polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene, by a case-control study. METHODS: By MRI, 147 subjects with SBI and 214 without cerebral infarctions (control group) were selected from participants of a health examination of the brain. Seventy-four patients with symptomatic subcortical infarction (SSI) from the same area were also included in the study. In addition to the control group, 2 more reference populations were recruited. Typing of the apo(a) size polymorphism was done by Western blotting with the use of an anti-apo(a) antibody. Genotypes of ACE and MTHFR were determined by polymerase chain reaction amplification of the genomic DNA and subsequent restriction enzyme digestion. RESULTS: The ACE polymorphism was not associated with either SBI or SSI. In contrast, the small apo(a) was associated with both SSI and SBI. The MTHFR polymorphism was associated only with SSI. The association of MTHFR and apo(a) was greater in the younger subjects. CONCLUSIONS: Among the 3 genetic polymorphisms studied, only the apo(a) size polymorphism is a risk factor for SBI.

Effects of apolipoprotein A gene polymorphisms on lipoprotein (a) concentrations in Japanese.

1. Elevated plasma lipoprotein (a) (Lp(a)) concentrations have been correlated with an increased risk of premature cardiovascular disease. The plasma Lp(a) concentration is quantitatively heritable and the apolipoprotein (Apo) A gene is known as a major locus-determining Lp(a) concentration. 2. The aim of the present study was to evaluate the genetic effect of polymorphisms in the 5'-untranslated region (UTR) of the ApoA gene on plasma concentrations of Lp(a). 3. We analysed two sequence variations in the 5'-UTR, a pentanucleotide repeat (PNR) polymorphism and haplotypes composed of three single base substitutions, in 325 Japanese subjects. The ApoA size polymorphism was also analysed by western blotting. 4. The plasma Lp(a) concentration was inversely correlated with the size of the ApoA molecule. Both PNR and the haplotype polymorphisms had significant effects on serum Lp(a) concentrations (P = 0.001 and 0.004, respectively) when the effects were evaluated by ANCOVA using the ApoA size polymorphism as a covariate. 5. When a stratified subpopulation with a larger ApoA size was analysed, both variations influenced or tended to influence the serum Lp(a) concentration, confirming the results of the ANCOVA. 6. Pentanucleotide repeat showed a tight linkage disequilibrium with the haplotypes. This disequilibrium may account for the apparent effects of PNR on Lp(a) concentrations.

Biochemical and pharmacological characterization of FR134043, a novel elastase inhibitor.

FR134043, disodium(Z,1S,15S,8S,24S,27R,29S,34S,37R)-29-ben zyl-21-ethylidene-27-hydroxy-15-isobutyrylamino-34-isopropyl-31,37 -dimethyl-10,16,19,22,30,32,35,38-octaoxo-36-oxa-9,11,17,20,23,28, 31,33-octaazatetracyclo[16.13.6.1(24),(28).0(3),(8)]octatricont a-3,5,7-trien-5,6-diyl disulfate, is a water-soluble inhibitor of human neutrophil elastase with a molecular mass of 1166.15 Da. FR134043 demonstrated a characteristic competitive inhibition of human neutrophil elastase with a Ki of 8 nM. In studies using synthetic substrates, FR134043 inhibited both neutrophil elastase activity and porcine pancreatic elastase activity with IC50 values of 35 nM and 49 nM respectively. FR134043 also inhibited hydrolysis of bovine neck ligament elastin by human neutrophil elastase with an IC50 value of 210 nM. In in vivo experiments, FR134043 protected animals against human neutrophil elastase (50 microg/animal)-induced lung hemorrhage in hamsters with an ED50 value of 3.1 microg/animal for intratracheal administration and 5.0 mg/kg for intravenous administration. Subcutaneous treatment with FR134043 significantly suppressed human neutrophil elastase (20 microg/paw)-induced paw edema in mice with an ED50 value of 3.3 mg/kg when evaluated 4 h after elastase injection. The potency of FR134043 given intratracheally to protect against porcine pancreatic elastase (100 microg/animal)-induced emphysema in hamsters was relatively low (Quasi-static lung compliance; ED50 = 1590 microg/animal) compared to that in acute animal models. FR134043 (10 mg/kg per h i.v. infusion) significantly improved lipopolysaccharide (0.25 mg/kg per h i.v. infusion)-induced thrombocytopenia and some coagulation parameters in rats. These results suggest that systemic administration of FR134043 would be advantageous over intratracheal administration of FR134043 for the treatment of adult respiratory distress syndrome, septic shock and pulmonary emphysema and other pathophysiologic conditions in which elastases are thought to be involved.

Nonpeptide mimic of bradykinin with long-acting properties at the bradykinin B2 receptor.

Kinins, members of a family of peptides released from kininogens by the action of kallikreins, exhibit a variety of biological activities including vasodilation, increased vascular permeability, contraction of smooth muscle cells, and activation of sensory neurons. However, investigation of the physiological actions of kinins has been greatly hampered because its effects are curtailed by rapid proteolysis in blood, lung, and liver. We describe the pharmacological characteristics of a novel nonpeptide bradykinin receptor agonist FR190997 (8-[2,6-dichloro-3-[N-[(E)-4-(N-methylcarbamoyl)cinnamidoacetyl ]-N-methylamino]benzyloxy]-2-methyl-4-(2-pyridylmethoxy)quinoli ne). FR190997 markedly stimulated phosphatidylinositol hydrolysis in Chinese hamster ovary cells permanently expressing the human bradykinin B2 receptor. The response of phosphatidylinositol hydrolysis was antagonized by the B2 receptor selective antagonist Hoe 140 (D-Arg-[hydroxyproline3,beta-thienylalanine4,D-Tic7,++ +Oic8]bradykinin). In competitive experiments using membranes prepared from Chinese hamster ovary cells expressing the human bradykinin receptor subtypes, FR190997 showed a high affinity binding to the B2 receptor with IC50 value of 5.3 nM and no binding affinity for the B1 receptor. In vivo, FR190997 mimics the biological action of bradykinin and induces hypotensive responses in rats with prolonged duration. Therefore, FR190997 is a highly potent and subtype-selective nonpeptide agonist which displays high intrinsic activity. This compound should represent a powerful tool for further investigation of the physiology and pathophysiology of bradykinin receptors.

FR146687, a novel steroid 5 alpha-reductase inhibitor: in vitro and in vivo effects on prostates.

BACKGROUND: Steroid 5 alpha-reductase is implicated in the pathogenesis of benign prostatic hyperplasia (BPH). We studied the in vitro and in vivo effects of FR146687, a new inhibitor of 5 alpha-reductase. METHODS: Two isozymes of rat and human 5 alpha-reductases were expressed in 293 cells. In vivo effects of drugs were evaluated on rat and dog prostates. Castrated immature rats were injected with testosterone propionate (TP) or 5 alpha-dihydrotestosterone propionate (DHTP) to induce growth of the ventral prostates. Testosterone and 5 alpha-dihydrotestosterone (DHT) contents in rat and dog prostates were measured by gas chromatography-mass spectrophotometry (GC-MS). RESULTS: FR146687 showed noncompetitive inhibition in both isozymes and no inhibitory effects on other steroid oxidoreductases. In mature rats and castrated immature rats treated with TP, FR146687 dose-dependently reduced ventral prostate and seminal vesicle weight at doses above 0.1 mg/kg, while castrated immature rats treated with DHTP were not affected by FR146687. FR146687 showed more potent reduction of rat prostates than finasteride. DHT concentration in the prostates was significantly reduced when FR146687 was administered to rats and beagles. CONCLUSIONS: FR146687 is a dual inhibitor for 5 alpha-reductase isozymes and significantly reduced the growth and DHT content in the prostate.

Novel subtype-selective nonpeptide bradykinin receptor antagonists FR167344 and FR173657.

We describe the receptor binding and antagonistic properties of two novel nonpeptide antagonists, FR167344 (3-bromo-8-[2,6-dichloro-3-[N-[(E)-4-(N,N-dimethylcarbamoyl)cinnamido acetyl]-N-methylamino]benzyloxy]-2-methylimidazo[1,2-a]pyridine hydrochloride) and FR173657 (8-[3-[N-[(E)-3-(6-acetamidopyridin-3-yl)acryloylglycyl]-N-m ethylamino]-2,6-dichlorobenzyloxy]-2-methylquinoline), for the human bradykinin receptor subtypes (B1 and B2). In competitive experiments using membranes prepared from Chinese hamster ovary cells expressing the bradykinin receptor subtypes, FR167344 and FR173657 showed a high affinity binding to the B2 receptor with IC50 values of 65 and 8.9 nM, respectively, and no binding affinity for the B1 receptor. FR167344 and FR173657 inhibited the B2 receptor-mediated phosphatidylinositol (PI) hydrolysis and produced a concentration-dependent rightward shift in the dose-response curve to bradykinin. This shift was accompanied by a progressive reduction of maximal response. Estimated pA2 values for the antagonism of bradykinin-induced PI hydrolysis by FR167344 and FR173657 were 8.0 and 9.0, respectively. FR167344 and FR173657 showed no stimulatory effects on PI hydrolysis. Therefore, FR167344 and FR173657 are potent, highly selective, and insurmountable antagonists for the human bradykinin B2 receptor.

[Apo(a) phenotype as a risk factor for the silent brain infarction].

Silent brain infarction (SBI) in the penetrating arteries is thought to be one of risk factors for overt cerebral stroke and vascular dementia. Although both Lp(a) concentration and apo(a) phenotype have been reported as risk factors for atherothrombotic infarction in cortical arteries, the roles of Lp(a) in the pathogenesis of lacunar infarction in the penetrating arteries remains controversial. We assessed the importance of apo(a) phenotype as a risk for SBI using a case control analysis. The frequency of low molecular weight phenotype (allele a) of apo(a) was significantly higher in subjects with SBI than in those without SBI. Relative risk for SBI was significantly higher in subjects with allele a than in subjects without allele a. Apo(a) phenotype was indicated to be one of the risk factors for SBI.

Effects of FR145237, an acyl-CoA:cholesterol acyltransferase inhibitor, on diet-induced hypercholesterolemia in diabetic rats.

Recent studies have shown that acyl-CoA:cholesterol acyltransferase (ACAT) plays an important role in the initiation of diabetes-associated hypercholesterolemia. To confirm this hypothesis, effects of a potent ACAT inhibitor, FR145237, on diet-induced hypercholesterolemia were examined in streptozotocin (STZ)-induced diabetic rats. One-week feeding of 1% cholesterol and 0.5% cholic acid to normal rats and STZ-induced diabetic rats increased plasma cholesterol levels in both groups, and the response was more remarkable in the STZ rats than in the normal ones (1266 +/- 476 mg/dl and 146 +/- 7 mg/dl, respectively). FR145237 dose-dependently reduced the rise in plasma cholesterol levels in the STZ rats and the levels were almost normalized by treatment with 1 mg/kg/day of the compound. These results suggest that hyperresponse to dietary cholesterol was induced in the STZ rats and that ACAT is involved in the hyperresponse. The effects of FR145237 on other plasma lipids such as high density lipoprotein (HDL) cholesterol and triglyceride (TG) levels were also examined.

Effects of basic fibroblast growth factor and ganglioside GM1 on neuronal survival in primary cultures and on eight-arm radial maze task in adult rats following partial fimbria transections.

The effects of basic fibroblast growth factor (bFGF) and ganglioside GM1 (GM1) were evaluated alone and simultaneously in two types of experiments. First, the neuronal survival of primary culture neurons from fetal rat brain was measured. Then, performance on radial maze task in adult male rats following bilateral partial Fimbria-Fornix transections (F-F lesion) was tested. In primary culture neurons, bFGF (1-10 ng/ml) supported the neuronal survival from three regions (hippocampus, cortex and septum) of embryonic rat brain. However, GM1 (0.1-10 micrograms/ml) did not support the neuronal survival from any regions. Survival of cultured neurons was not supported by addition of 0.1 ng/ml bFGF, but when bFGF (0.1 ng/ml) and GM1 (0.1, 1 microgram/ml) were given to the cultured neurons simultaneously, the number of surviving neurons increased significantly. In the eight-arm radial maze task, where only the same four arms were baited, F-F lesion produced substantial memory impairment. In this task, administration of bFGF (10 micrograms/ml) or GM1 (1 mg/ml) alone did not produce any effects. However, when they were given simultaneously, the number of working memory errors decreased significantly, in spite of no amelioration for hippocampal choline acetyl transferase (ChAT) depletion. These findings indicate that actions of bFGF may be potentiated by the addition of GM1 in both primary neuronal cultures and radial maze task performance. These results suggest that the combination of bFGF and GM1 may synergistically improve spatial memory deficits.

Plasma cholesterol reducing effect of FR129169, a novel acyl-CoA:cholesterol acyltransferase inhibitor, in the rat.

FR129169 (FR) (N-(1,2-diphenylethyl)-2-octyloxyphenylacetamide) has been found to inhibit acyl-CoA:cholesterol acyltransferase (ACAT) activities in intestinal microsomes of rats and rabbits and the liver homogenate of rats with IC50 values of around 1.0 x 10(-7) M. The inhibitory activity was 2-3 times more potent than that of CI 976 (CI). When FR in a dose of 10 mg/kg/day was administered as a dietary admixture, plasma cholesterol levels were normalized in rats fed a high cholesterol diet, but lower doses of FR had no effect. Similar results were obtained in the rats treated with CI. The ex vivo study where hepatic ACAT activity was measured after oral dosing of the two inhibitors revealed that ACAT activity was significantly reduced in rats treated with FR in a dose of 10 mg/kg/day, while CI reduced the activity at lower doses such as 0.1 and 1 mg/kg/day. Since FR was not orally absorbed, it is speculated that the inhibitory activity of FR on hepatic ACAT in the ex vivo study results from the reduction of plasma cholesterol levels. These results suggest that FR exerted cholesterol-lowering activity mainly through inhibition of intestinal ACAT activity. The significance of intestinal ACAT inhibition by FR for therapeutic treatment of hypercholesterolemia is discussed.

Novel steroid 5 alpha-reductase inhibitor FK143: its dual inhibition against the two isozymes and its effect on transcription of the isozyme genes.

Recent cloning of the cDNAs for the two isozymes of steroid 5 alpha-reductase (EC 1.3.99.5) allowed individual expression of the isozymes and permitted us to investigate the action of steroid 5 alpha-reductase inhibitors against the individual isozymes without any ambiguity that may be caused by coexistence of the isozymes in tissue preparations. We examined the kinetic characteristics of FK143 (4-[3-[3-[bis(4-isobutylphenyl)methylamino]benzoyl]-1H-indol-1- yl]butyric acid), a novel nonsteroidal steroid 5 alpha-reductase inhibitor against cloned human and rat steroid 5 alpha-reductase isozymes. FK143 was shown to inhibit both isozymes equally. The mode of the inhibition of FK143 against both isozymes was noncompetitive. The inhibition constants Kie and Kies of FK143 for human types 1 and 2 were 27.0 and 19.6 nM and 19.9 and 14.5 nM, respectively. Species selectivity between human and rat of the inhibitory activity of FK143 against both isozymes was not found. We also examined the effect of FK143 on the in vivo expression of the genes encoding for the rat steroid 5 alpha-reductase isozymes. FK143 reduced the testosterone-induced increase in the amount of the type 1 mRNA in castrated rat, whereas it did not substantially affect the amount of the type 2 mRNA.

FK143, a novel nonsteroidal inhibitor of steroid 5 alpha-reductase: (1) In vitro effects on human and animal prostatic enzymes.

Steroid 5 alpha-reductase is an enzyme which converts testosterone into 5 alpha-dihydrotestosterone (DHT) and is implicated in the pathogenesis of benign prostatic hyperplasia (BPH) in men. We studied in vitro effects of FK143, a nonsteroidal new compound, on 5 alpha-reductase in human and animal prostates. Prostates were obtained from Wistar rats, Beagle dogs, and Cynomolgus monkeys as well as prostatic tissue from BPH patients obtained by the prostatectomy. Nuclear membrane fraction of prostates showed pH dependent 5 alpha-reductase activities, and inhibitory effects of drugs were assayed at pH 6.5. FK143 inhibited human prostatic 5 alpha-reductase in a dose-dependent manner with an IC50 of 1.9 nM and also inhibited animal 5 alpha-reductases with similar IC50 values. FK143 inhibited human and rat 5 alpha-reductases in a noncompetitive fashion while finasteride, a steroidal 5 alpha-reductase inhibitor, showed competitive inhibition. The affinities of FK143 for the human 5 alpha-reductase is constant at pH 5 and 6.5. No inhibitory effects were shown to other oxidoreductases. These results indicate that FK143 is a new type of potent and selective 5 alpha-reductase inhibitor.

FK143, a novel nonsteroidal inhibitor of steroid 5 alpha-reductase: (2) In vivo effects on rat and dog prostates.

FK143 is a nonsteroidal new inhibitor of steroid 5 alpha-reductase, an enzyme which converts testosterone into 5 alpha-dihydrotestosterone (DHT). We studied in vivo effects of FK143 on rat and dog prostates. FK143 was orally administered to mature male rats for 14 days. At doses above 1 mg/kg, FK143 significantly reduced the wet weights of the ventral prostate and seminal vesicle, but showed no effects on those of the epididymis, testis, and adrenal. Growth of ventral prostate and seminal vesicle was induced by the subcutaneous injection of testosterone propionate (TP) in the castrated young rats and was reduced by FK143 administration at doses above 3.2 mg/kg, while growth induced by 5 alpha-dihydrotestosterone propionate (DHTP) was not affected. FK143 had no binding affinity for the rat androgen receptor. FK143 showed neither estrogenic and antiestrogenic effects on the rat uterus nor androgenic effect on the rat prostate. Concentration of testosterone and DHT in the rat and dog prostates were measured by GC-MS, and administration of 10 mg/kg of FK143 significantly reduced the intraprostatic concentration of DHT. These results indicate that FK143 reduced the prostate growth by inhibiting 5 alpha-reductase activities in the prostates.

Subtype- and species-selectivity of a tachykinin receptor antagonist, FK888, for cloned rat and human tachykinin receptors.

We investigated the receptor-binding properties and potencies of FK888 (N2-[(4R)-4-hydroxy-1-(1-methyl-1H-indol-3-yl)carbonyl-L-prolyl]-N- phenylmethyl-3-(2-naphthyl)-L-alaninamide), a tachykinin receptor antagonist, for the rat and human tachykinin receptor subtypes (NK1, NK2 and NK3) expressed in transfected mammalian cells. In displacement analyses, using membrane preparations derived from monkey kidney COS-7 cells transiently expressing tachykinin receptor subtypes, FK888 showed a subtype selectivity for NK1 receptor and its affinity for the human NK1 receptor was 320-fold higher than that for the rat NK1 receptor, demonstrating species difference in its binding affinity. This was in marked contrast to FK224 (N-[N2-[N-[N-[N-[2,3-didehydro-N-methyl-N-[N-[3-(2-pentylphenyl )- propionyl]-L-threonyl]tyrosyl-L-leucynyl]-D-phenylalanyl]-L- allothreonyl]-L-asparaginyl]-L-serine-n-lactone) that was selective for NK1 and NK2 receptors with similar affinities for the rat and human receptors. In Chinese hamster ovary cells permanently expressing the human NK1 receptor, FK888 inhibited the substance P-induced phosphatidylinositol hydrolysis and produced a parallel shift in the dose-response curve for substance P. Schild analysis of the antagonism of phosphatidylinositol hydrolysis by FK888 yielded a pA2 value of 8.9 and a slope of 0.97 of the regression line. FK888 itself showed no stimulatory effect on phosphatidylinositol hydrolysis in Chinese hamster ovary cells expressing the human NK1 receptor. Thus, FK888 is a potent, competitive and selective antagonist for human NK1 receptor.