In vitro maturation of steroidogenic capacity of ovine fetal and neonatal adrenal cells.

Abstract

The in vitro production of total corticosteroids, corticosterone (B), and cortisol (F) by cultured adrenocortical cells from fetuses (115-120 days old) and newborn lambs exposed to ACTH-(1-24) was investigated in relation to the time of culture. Corticosteroids were measured by using an antibody against F, whereas B and F separately were each assayed by specific antibodies after their separation by thin layer chromatography. Basal corticosteroid production by fetal cells increased about 5-fold between days 1 and 6 of culture, whereas the production of B and F increased from 3 +/- (SE) 0.3 to 194 +/- 25 and 3.9 +/- 0.3 to 17.4 +/- 1.9 [ng (8 X 10(5) cells)-1 2 h-1], respectively. ACTH-(1-24) stimulation on day 6 further increased the production of corticosteroids (3.5-fold) and B (2-fold), but had no effect on that of F. When cells were exposed to ACTH-(1-24) from the first day of culture on, there was a dramatic enhancement of F production which became, by day 6, 100 times higher (1746 +/- 149) than in the case of cells maintained in ACTH-free medium. Basal corticosteroid production by nontreated neonatal adrenal cells increased between day 1 and 6, and this was mainly due to B, the production of which increased from 10.1 +/- 0.2 to 447 +/- 35. ACTH-(1-24) stimulation of these cells on day 6 increased 2-fold the secretion of F and 1.5-fold that of B. ACTH-(1-24) treatment (2 h/day for 5 days) of neonatal cells increased 11-fold their production of F as compared with cells cultured in ACTH-free medium, and to a lesser extent that of B. In the second set of experiments, pregnenolone (8 X 10(-5) M) was added to the medium and its conversion to B and F was measured. On day zero the production of B and F by untreated fetal cells was 31 and 16 times higher than that of cells incubated without pregnenolone but stimulated by ACTH-(1-24); however, on day 6 the increase was only 2 and 5 times higher, respectively. On day 6 production of B and F by ACTH-treated cells was modestly increased by the addition of pregnenolone. The capacity of freshly isolated neonatal adrenal cells (day zero) to convert pregnenolone to B and F was 10- and 150-fold higher, respectively, than that of cells from fetuses.(ABSTRACT TRUNCATED AT 400 WORDS)