Parathyroid Hormone and Mitochondrial Respiration

Abstract

Parathyroid hormone added in vitro stimulates anion-dependent respiration in isolated liver and kidney mitochondria. This response depends upon Mg⁺⁺ (or Mn⁺⁺) and substrate and is inhibited by uncouplers and inhibitors of electron transport but not by oligomycin or triethyltin, inhibitors of oxidative phosphorylation. The response is dosedependent and can be used as a biological assay for this hormone. As reported previously (18, 19), the respiratory stimulation is a concomitant of anion uptake. The nature of the coupling of these 2 processes is not known, but evidence is presented to show that there is a bidirectional flux of anion and that only the entry or uptake process is coupled to respiratory chain activity. The nature and site of coupling between ion transport and electron transport are discussed. (Endocrinology75: 431,1964)