Cortisol分泌量に関する検討とくに測定法並びに正常範囲について

抄録

Details of a procedure for estimating cortisol secretion rate (CSR) were presented and the validity of this method was investigated. Using this method, CSR in normal subjects, in subjects under stress and in patients with adrenocortical dysfunctions were estimated.
1) After an intravenous administration of a treacer dose of cortisol-1, 2-³H, 24-hr. urine was collected. Two major urinary metabolites of cortisol, tetrahydrocortisol (THF) and tetrahydrocortisone (THE), were purified paper-chromatographically and their specific activities were determined by liquid scintillation counting and Porter-Silber method. The estimated value of CSR was calculated by dividing total administered radioactivity by the specific activity of THF or THE.
For purifying both THF and THE, ethylene dichloride-formamide system was used as the first paper chromatography. In the next step, Bush B₅ system was used for purifying THF, and E2B system or Bush B₅ system for purifying THE.
2) When E2B system was used as the second paper chromatography for purifying THE, two values of CSR, wihch were independently calculated from the specific activity of THF and from that of THE, did not agree with each other.
In order to find which value reflects more actual cortisol secretion rate, known amounts of cortisol were given to the patients with hypoadrenocorticism, and apparent CSR were estimated. The estimated values agreed with the doses administered when calculation was made from the specific activity of THF, while they showed much smaller values with calculation from that of THE. This fact suggested that cortisol metabolite or metabolites, not Porter-Silber chromogenic, contaminated THE. When Bush B₅ system was substituted for E2B system as the second paper chromatography for purifying THE, the values of CSR calculated from the specific activity of THE approached the values from THF.
3) The value of CSR calculated from the specific activity of THF was 14.6±3.3 (S.D.) mg/day in 10 resting normal subjects, and was 13.7±3.2 mg/day in 10 lightly working normal subjects. There was no significant difference between the two groups. A slightly higher value, 17.8±5.0 mg/day, was obtained from 8 heavy muscle laborers.
4) The value of CSR in 10 resting and 10 lightly working normal subjects, 14.1±3.2 mg/day, agreed with the smallest normal value that was previously presented by foreign investigators. This may be due to the smaller body size of Japanese people than that of foreign people.
At the same time, CSR in subjects under stress and in patients with adrenocortical hyper-and hypofunctions were studied. From these data, it was finally justified to adopt 7.8-20.5 mg/day as the normal range.
In addition, CSR per kg of body weight and per m² of body surface area were also evaluated. The adopted normal ranges were 145-358 μg/kg/day and 5.3-12.6 mg/m²/day.