title: Special features of Pi transport in pig heart and rat liver mitochondria as revealed by 6,6'-dithiodinicotinic acid (CPDS).
abstract: CPDS (6,6'-dithiodinicotinic acid), a non permeant thiol agent which affects several mitochondrial functions in a way different to that of mersalyl [18-19] revealed striking differences between the phosphate translocating systems of pig heart and rat liver mitochondria. Pi entry was measured either by swelling in 0.12 M ammonium phosphate or by rapid centrifugation in 32Pi medium. Pi efflux was measured after preloading of mitochondria with 32Pi, by exchange against Pi or malate; the "ATP-FCCP" system has been tested previously [19]. In pig heart mitochondria, Pi entry seems to proceed exclusively via the Pi/OH- carrier; CPDS completely inhibits this transport and the energy-linked functions. In contrast n-butyl-malonate does not affect the Pi-entry and the energy-linked functions. The Pi efflux is not affected either by CPDS or mersalyl, which do not produce a swelling in the "ATP-uncoupler system". In rat liver mitochondria, CPDS inhibits only the Pi/OH- carrier; both CPDS and n-butylmalonate are necessary to inhibit completely Pi entry. CPDS as well as mersalyl provokes a swelling in the presence of the "APT-uncoupler system". The results suggest two distinct functions of phosphate transport in both types of mitochondria.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002122:Calcium Chloride / Q000494:pharmacology; D002498:Centrifugation; D004220:Disulfides / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008314:Malonates / Q000494:pharmacology; D008634:Mersalyl / Q000494:pharmacology; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000378:metabolism*; D008933:Mitochondrial Swelling / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D009539:Nicotinic Acids / Q000494:pharmacology*; D009840:Oligomycins / Q000494:pharmacology; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010710:Phosphates / Q000378:metabolism*; D051381:Rats; D012402:Rotenone / Q000494:pharmacology; D013439:Sulfhydryl Reagents; D013552:Swine
chemical_list: D004220:Disulfides; D005971:Glutamates; D008314:Malonates; D009539:Nicotinic Acids; D009840:Oligomycins; D010710:Phosphates; D013439:Sulfhydryl Reagents; D012402:Rotenone; C001102:6,6'-dithiodinicotinic acid; D008634:Mersalyl; D002122:Calcium Chloride