G. Alvarezfernandez et al., NEWLY-HATCHED CHICK OVARIAN CELL SUBPOPULATIONS METABOLIZE DISTINCTIVELY PROGESTIN AND ANDROGEN PRECURSORS, General and comparative endocrinology, 97(1), 1995, pp. 31-41
The aim of this study was to characterize the ability of four differen
t cell fractions (F1, F2, F3, and F4), isolated from the ovary of newl
y hatched chick by means of subsequent metrizamide gradients (0-15%),
to metabolize progestins and androgens. The results showed the presenc
e of 17 alpha-hydroxylase/C17-20 lyase and 3 beta-hydroxysteroid dehyd
rogenase/isomerase (3 beta-HSD) activities in the typical steroidogeni
c cells isolated in F1 (d = 1.012 g/ml). Primary oocytes present in F2
(d = 1.037 g/ml) did not show relevant steroid metabolism in the vari
ous assays that were carried out. Fractions 3 (d = 1.055 g/ml) and 4 (
d = 1.071 g/ml), which contained a mixture of prefollicular and poorly
differentiated epithelial cells, presented both 5 beta-reductase and
aromatase activities, whereas 17 beta-HSD activity was mainly located
in the cells of fraction 3. It is highly possible that poorly differen
tiated epithelial cells of fractions 3 and 4 are responsible for the s
teroidogenic activity. We conclude that in newly hatched chick ovary,
typical steroidogenic cells metabolize progestins to androgens, and po
orly differentiated epithelial cells further aromatize androgens to es
trogens. In addition, we suggest the existence of at least two metabol
ically distinct poorly differentiated epithelial cell subpopulations,
one presenting SP-reductase and aromatase activities and another exhib
iting 17 beta-HSD activity. (C) 1995 Academic Press, Inc.