title: On the metabolism of the rod outer segments.
abstract: 1. The high energy phosphate esters available for the luminescent reaction of the firefly lantern extract correspond, in the dark adapted rods of the frog, to 7 X 10(-16) mole of ATP per rod, corresponding to ca. 1-4 mM. 2. Rods isolated from light adapted eyes contain a smaller amount. 3. The high energy phosphate esters are reduced spontaneously at a rate of 50% in 24 min, in the isolated rods in darkness. 4. Bleaching a few per cent of the rhodopsin molecules of a rod suspension induces a 60% decrease achieved in less than 12 sec. 5. The ionophore A23187 decreases the high energy phosphate esters when the extracellular free Ca concentration is greater than 10(-7) M, suggesting that ATP is consumed in pumping Ca ions out of the rods, or into the disks contained in the rods, or both.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D003623:Dark Adaptation; D004594:Electrophysiology; D010786:Photoreceptor Cells / Q000187:drug effects / Q000378:metabolism*; D011892:Rana catesbeiana; D012243:Rhodopsin / Q000378:metabolism
chemical_list: D000001:Calcimycin; D000255:Adenosine Triphosphate; D012243:Rhodopsin; D002118:Calcium