SERUM CORTICOTROPHIN, PLASMA CORTISOL AND URINARY EXCRETION OF 17-KETOGENIC STEROIDS IN THE ELDERLY (AGE GROUP: 66–94 YEARS)

Abstract

ABSTRACT The serum corticotrophin concentrations was determined in 28 elderly subjects (70–94 years) by the radioimmunochemical double-antibody-technique. In 5 elderly subjects, the corticotrophin concentration was studied throughout the 24-hour period. The plasma cortisol concentration was determined by means of a double-isotope-derivative technique in 69 elderly subjects (66–94 years). In 10 elderly and 8 younger subjects the concentration was checked throughout the 24-hour period. The urinary excretion of 17-ketogenic steroids was determined in a total of 80 elderly subjects (66–94 years). For comparison corticotrophin and cortisol measurements in young volunteers assayed by identical methods were used and partly carried out in cooperation with other investigators. At 8 a. m. the average corticotrophin concentration was 101.8 ± 55.0 (sd) pg/ml of serum and the average cortisol concentration was 15.0 ± 4.60 (sd) μg/100 ml of plasma. No significant age or sex variation could be detected. With regard to both hormones, the circadian variations were marked with parallel changes in the concentrations of corticotrophin and cortisol. The highest concentration was measured in the morning and the lowest in the evening. The urinary excretion of 17-ketogenic steroids showed a tendency to decrease with increasing age. The regression equation for females was ȳx = −0.07x + 11.42, for males ȳx = −0.22x + 26.59.