Temporal secretory responses of cultured hamster adrenals

Abstract

1. 1. Comparison of adrenocortical secretory patterns measured by radio-acetate incorporation into corticosteroid and by acid fluorescence of corticosteroids secreted by cultured hamster adrenals confirm earlier estimates of a persistent daily rhythm maintained in vitro. 2. 2. The phase relationships between the specific activity of isolated steroids and the amount of corticosteroid are not, however, identical. 3. 3. The amplitude and phase of the secretory rhythm may be altered by ACTH in the nutrient medium. 4. 4. Continuous doses of ACTH have little effect on the phase of the rhythm, but show dose-related alterations of the amplitude of daily variation. 5. 5. Pulse doses of ACTH have an effect on the amplitude of secretion long after the glands have been washed, but also effect changes in the phase of the daily pattern of secretion. 6. 6. The inhibitor, metopirone (SU-4885), when delivered in the same pulse as the ACTH, blocks the ACTH effect.