SulfonesPurinesPhosphodiesterase 5 InhibitorsPiperazinesCitrate (si)-SynthasePhosphodiesterase InhibitorsCyclic Nucleotide Phosphodiesterases, Type 5Citric AcidErectile Dysfunction3',5'-Cyclic-GMP PhosphodiesterasesVasodilator AgentsPenile ErectionPotassium CitrateHypertension, PulmonaryOxo-Acid-LyasesCalcium CitrateCyclic GMPCarbolinesImpotence, VasculogenicPenisAdministration, OralClomiphenePhosphoric Diester HydrolasesPyrimidinonesTriazinesPriapismPulmonary ArteryDouble-Blind MethodCross-Over StudiesTricarboxylic AcidsMalatesOxaloacetatesClitorisDose-Response Relationship, DrugTreatment OutcomeGallium RadioisotopesNitric OxideDrug Therapy, CombinationCyclic GMP-Dependent Protein KinasesHypertrophy, Right VentricularPulmonary Wedge PressureVascular ResistanceFerric CompoundsDihydroergocristineEjaculationAconitate HydrataseIloprostHemodynamicsPapaverineIsocitratesBlood PressureAluminumFertility Agents, FemaleIsocitrate DehydrogenaseTime FactorsBismuthAntihypertensive AgentsOxaloacetic AcidCyclic Nucleotide Phosphodiesterases, Type 2Rats, WistarKetoglutaric AcidsAlprostadilDrug InteractionsOrgasmEpimediumCoitusHydrogen-Ion ConcentrationGuanylate CyclaseMalate DehydrogenaseAcetyl Coenzyme APentylenetetrazoleDrug SynergismMagnesium CompoundsVasodilationPulmonary CirculationAcetatesEsophageal Motility DisordersKineticsCREST SyndromeDisease Models, AnimalCoenzyme ADicarboxylic Acid TransportersOxygen ConsumptionMilrinoneMonocrotalineEpoprostenolAconitic AcidRanitidineGalliumRats, Sprague-DawleyPhosphofructokinase-1Exercise TestHeart RateMagnesium HydroxidePyruvatesNG-Nitroarginine Methyl EsterExercise TolerancePlacebosLeuconostocImidazoles