In vitro maturation of ovine fetal adrenal cells adenylate cyclase: corticotropin-dependent and independent development of the response to corticotropin
Durand, P.; Cathiard, A.M.; Saez, J.M.
Biochemical and Biophysical Research Communications 106(1): 8-15
1982
ISSN/ISBN: 0006-291X PMID: 6285917 Document Number: 185036
ACTH1-24 stimulation of cAMP production by fetal and newborn ovine adrenal cells maintained in culture for 6 days was investigated in absence or presence of ACTH1-24. When fetal cells were exposed to ACTH for 2 h per day from day 1, the cAMP response to ACTH1-24 increased during the course of the experiment to become 40-fold higher on day 6, than that observed on day 1. When ACTH1-24 was continuously present in the culture medium, the increase of the acute response to the hormone was weaker from day 4 onwards than in the case of cells exposed to ACTH1-24 for only 2 h per day. ACTH1-24-stimulated cAMP production on day 6 of fetal cells cultured in ACTH-free medium for 5 days was 25-fold higher than the response obtained on day 1. When newborn adrenal cells were treated with ACTH1-24 for 2 h per day, no significant change on ACTH1-24 treatment induced some decrease. Thereafter, the hormonal responsiveness increased in both cases, but was lower in the case of continuous ACTH1-24 treatment. On the last day of experiment, the response of cells cultured without ACTH was 3- to 5-fold higher than that of cells treated with ACTH1-24. These data and those reported previously suggest that during fetal life maturation of ovine adrenal adenylate cyclase is inhibited by some factor(s). ACTH can overcome this inhibition and accelerate the spontaneous maturation of adenylate cyclase. Apparently, the action of ACTH on both mature and fetal adrenal cells is a dichotomic process including sensitization and desensitization, the latter being less marked in immature cells.