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On the intracellular distribution of [4-14C]cortisol in rat liver

1967; Elsevier BV; Volume: 136; Issue: 1 Linguagem: Inglês

10.1016/0304-4165(67)90321-2

1872-8006

David J. Morris, Frederick W. Barnes,

Diet and metabolism studies

Abstract In the experiments reported here, it is hoped that an approach to eventual understanding of the role of cortisol in the liver can be made through separation of possible complexes formed by cortisol in the cell. 1. 1. Intraperitoneal and intravenous injections of [4-14C]cortisol (2 μC and 0.25 μC respectively) showed the label to be distributed in the microsomes, the supernatant fraction, and to a lesser extent, the mitochondria, in rat liver. High concentrations of the label in these fractions could be found as early as 30 sec after the intravenous injections. 2. 2. The peaks in the percentage supernatant values at 4 and 7 min, followed by a continual rise in the value after 7 min, suggest that the label passes over to a second supernatant step, from the first supernatant step, or from the microsomes, or both. 3. 3. A set of experiments in which a pulse of [14C]cortisol was followed by a chase of unlabeled cortisol gave results which indicated two types of attachment of the label to the microsomes in the first step. Ether extraction, electrophoresis and the pulse-labeling experiments, all suggest the lack of exchangeability of the labeled substance in the supernatant fractions and the stability of its binding to this fraction. 4. 4. In a series of intravenous injections of [14C]cortisol in male and female adrenalectomized rats, it was shown that the cortisol distribution in adrenalectomized male rats was different from that in the female rats, suggesting the possibility that normal “cortisol activity” in the two sexes is different. 5. 5. In experiments where the injected quantities of label varied from very small (0.2 μg) to larger (inducing) amounts (2.5 mg), the distribution of the label was found to be very similar to that obtained with the 0.25 μC (2.0 μg) experiments.