The Journal of The Japanese Society of Balneology, Climatology and Physical Medicine
Online ISSN : 1884-3697
Print ISSN : 0029-0343
ISSN-L : 0029-0343
Study of Adrenocortical Function in Fever
Effect of high temperature on corticoidogenesis in isolated bovine adrenocortical cells
Naoko KOSUGEKen-ichi KUBOYAMANoboru NAKAMICHI
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1996 Volume 59 Issue 2 Pages 93-98

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Abstract

To study the adrenocortical function in fever, we examined the effect of high temperatures on the corticoidogenesis (CG) in isolated bovine adrenocortical cells. To evoke CG, a stimulus was given using adrenocorticotropic hormone (ACTH, 1pM to 10nM), which stimulates the receptor operated Ca2+ channel (ROC) and adenylate cyclase activity; dibutyryl cyclic AMP (db-cAMP, 1mM), which mimics intracellular action of cyclic AMP; and high (30mM) K+, which activates the voltage dependent Ca2+ channel (VDC). Cells were incubated for 1 hour with each of the above mentioned secretaogues at 37°C, 40°C, and 42°C (only for ACTH). Compared with incubation at 37°C, the log dose response curve of ACTH shifted to the right, the maximal effect decreased to about 60% at 40°C, and CG ceased at 42°C. The use of Ca2+ (1.2mM) alone evoked CG via the nonspecific Ca2+ channel (NSC) at 37°C, but not at 40°C. 30mM K+-induced CG decreased to below 50% at 40°C, but 1mM db-cAMP-induced CG decreased only to 80%. However, the conversion of 25-hydroxycholesterol to corticoid was not affected at 40°C
The results of these experiments show that VDC and NSC are not the main factors of CG at 40°C and that the enzyme activity beyond the side chain cleavage of cholesterol is not affected. Since the increases in cyclic AMP production and intracellular Ca2+ are essential in various stimulants-induced CGs, it is suggested that adenylate cyclase and ROC play a more important role in CG at 40°C than VDC and NSC.

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