ABSTRACT
A full-length 1,209 bp cDNA encoding the human sex steroid-binding protein of plasma (SBP or SHBG) and testis (ABP) was constructed and expressed in BHK-21 cells. The sequence agrees with the published gene and protein sequences. The cells were found to secrete SBP following transfection and G418r selection. The recombinant protein binds 5 alpha-dihydrotestosterone with a Kd of 0.28 nM. It also binds testosterone and 17 beta-estradiol but not progesterone, estrone or cortisol revealing a steroid-binding specificity identical to that of human SBP. SDS-PAGE patterns are less complex than human SBP and show a monomeric molecular weight of about 43 kDa.
Subject(s)
Sex Hormone-Binding Globulin/genetics , Testis/metabolism , Base Sequence , Blood , Cloning, Molecular , DNA , Gene Expression , Humans , Male , Molecular Sequence Data , Mutagenesis, Site-Directed , Organ Specificity/genetics , Recombinant Proteins/metabolism , Restriction Mapping , Sex Hormone-Binding Globulin/metabolismABSTRACT
The putative antidepressant drug tiflucarbine (BAY P 4495) has previously been shown to inhibit calmodulin-dependent cyclic nucleotide phosphodiesterase competitively with respect to calmodulin. In order to determine whether this effect is mediated by a direct interaction with calmodulin, we measured the effects of radiolabelled triflucarbine in a direct ligand binding assay, using agarose-immobilized calmodulin. [3H]Tiflucarbine associated with low micromolar affinity with an apparently homogeneous class of recognition sites on calmodulin-agarose. No binding could be observed on calmodulin-deficient agarose. The effect was specific, saturable and reversible. Triflucarbine was the most potent calmodulin antagonist from a variety of structural analogues examined. The potencies of these derivatives to inhibit calmodulin-stimulated phosphodiesterase significantly correlated with their affinities towards the tiflucarbine binding site on calmodulin. No such correlation was evident when structurally unrelated reference compounds were tested. The association of tiflucarbine with calmodulin thus appears pharmacologically specific and selective and possibly contributes to the potent antidepressant activity of the drug.
Subject(s)
Antidepressive Agents/metabolism , Calmodulin/metabolism , Indoles/pharmacology , Thiophenes/pharmacology , 3',5'-Cyclic-AMP Phosphodiesterases/metabolism , Animals , Binding Sites/drug effects , Cattle , Cyclic AMP/metabolism , Cyclic Nucleotide Phosphodiesterases, Type 1 , Kinetics , Ligands , Protein Binding , Serum Albumin, Bovine/metabolismABSTRACT
In animal behavioral tests of anxiolytic efficacy, TVX Q 7821 was active and equipotent with diazepam, but did not produce muscle relaxation or anti-convulsant effects. The high affinity, specific binding of 3H-TVX Q 7821 to calf hippocampal membranes was displaced by serotonin (5-HT) but not by diazepam. Similarly, unlabeled TVX Q 7821 displaced 3H-5-HT but not 3H-flunitrazepam binding. Since ketanserin (a putative 5-HT2 ligand) was equally weak in displacing labeled 5-HT or TVX Q 7821, TVX Q 7821 may preferentially bind to 5-HT1, receptors.
Subject(s)
Brain/metabolism , Pyrimidines/pharmacology , Receptors, Serotonin/drug effects , Aggression/drug effects , Analgesia , Animals , Avoidance Learning/drug effects , Diazepam/pharmacology , Electroshock , Flunitrazepam/metabolism , Humans , Male , Mice , Mice, Inbred Strains , Pyrimidines/metabolism , Receptors, Serotonin/metabolism , Serotonin/metabolismABSTRACT
Tienocarbine (1,9-dimethyl-7,8,9,10-tetrahydrothieno[3,2-e] pyrido[4,3-b] indole lactate) in oral doses of 10 mg X kg-1 lowers dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striata of rats without influencing contents of biogenic amines; this points to a reduced dopamine (DA) turnover. This effect is still present after 28 days of daily application. At the same time the serotonin (5-HT) turnover is not influenced. Tienocarbine displaces 3H-DA and 3H-spiperone from their specific binding sites in the nucleus caudatus of calf brain. Structural variation results in preponderance of either dopamineagonistic (turnover lowered) or antagonistic (turnover increased) properties of the molecules. The whole class of compounds therefore can be considered as mixed dopamine agonists-antagonists.
Subject(s)
Brain Chemistry/drug effects , Catecholamines/metabolism , Indoles/pharmacology , Thiophenes/pharmacology , 3,4-Dihydroxyphenylacetic Acid/metabolism , Animals , Antipsychotic Agents/metabolism , Binding, Competitive/drug effects , Caudate Nucleus/metabolism , Dopamine/metabolism , Homovanillic Acid/metabolism , Hydroxyindoleacetic Acid/metabolism , Male , Norepinephrine/metabolism , Putamen/metabolism , Rats , Rats, Inbred Strains , Serotonin/metabolism , Spiperone/metabolism , Structure-Activity RelationshipABSTRACT
The chemical structure of the indometacin molecule was systematically modified with the aim of producing a substance with increased anti-inflammatory activity and improved tolerance. In addition to the variations of the methylene group of the indole-3-acetic acid and substituents on the indole nucleus of indometacin, particular attention was paid to the modification of the carboxyl group of the acetic acid side chain. Among the indometacin esters, one derivative, the [1-(4-chlorobenzoyl)-5-methoxy-2-methylindole-3-acetoxy] acetic acid (54), showed an activity approximately twice that of indometacin in the kaolin edema test in the rat paw. Chemical modification of the new compound 54 did not further improve the activity. These studies suggest that specific substitutions on the indole nucleus, in combination with the acetic acid side chain as in 1, and especially the acetoxy acetic acid side chain in 54 are responsible for the high anti-inflammatory activity of this class of substances. Several methods for the synthesis of acemetacin are described.
