1973 年 14 巻 2 号 p. 162-164
1) Neither significant differences in plasma corticosterone level at rest nor marked differences in its diurnal variation except for a possible displacement of the peak in female SHR were observed between spontaneously hypertensive rats (SHR) and normotensive rats (NR). 2) Response in plasma corticosterone to various stress loadings was not increased in SHR, but rather decreased under certain conditions in comparison with NR. 3) Biological half-life of plasma corticosterone determined from the decline in exogenously loaded corticosterone in adrenalectomized rats was not significantly different between SHR and NR. 4) Analysis of adrenal venous steroid profile in SHR and NR under the maximum stimulation by ACTH showed that the conversion ratio from progesterone to DOC was decreased in SHR. 5) These results indicate that there probably is no acceleration of synthesis and metabolism of adrenal corticosterone itself in SHR compared with NR, and raised a possibility of relative impairment of 21-β-hydroxylase in SHR. A speculated compensatory metabolic pathway from progesterone via 18- or 17-α-hydroxylation as well as the substrain difference in steroidogenesis in relation to vascular vulnerability still remains to be clarified by further study.