The effect of insect hormones and of 2 : 4-dinitrophenol on the mitochondrion of Locusta migratoria L.

Abstract

Mitochondria were prepared from the fat body and thoracic muscles of Locusta migratoria and Schistocerca gregaria. The respiration of the mitochondria in a sodium succinate substrate was measured, and the effects of adding various substances on the oxygen consumption of the mitochondria recorded. The addition of 2 : 4-dinitrophenol (DNP) in physiological quantities resulted in a decrease in oxygen consumption when compared with a control on mitochondria prepared from adult Locusta migratoria. It increased the oxygen consumption of mitochondria from the fifth instar of Schistocerca gregaria. The addition of the corpora allata to mitochondria prepared from adult Locusta migratoria caused an increase in oxygen consumption whilst their addition to those prepared from fifth instar Schistocerca gregaria decreased oxygen consumption. When both DNP and corpora allata were present together the oxygen consumption was stimulated in both Locusta and Schistocerca. The amount of stimulation was slightly greater than when either was present alone. The effect of the addition of the corpora cardiacum to preparations of adult mitochondria was to depress their oxygen consumption. One of the sites of the action of the corpora allata hormone is shown to be the mitochondrion. The possibility that the known action of DNP might provide a further clue to the site of action of the C.A. hormone is discussed.