Hydroxylated sterols : matabolism and effects on steroid production and steroid uptake
1989
textabstractThe isolated rat adrenal cell was used as a model system. The
isolation technique for rat adrenal cells has been extensively studied : in
our laboratory (Falke et al., 1975a,b, 1976a,b) . Starting with these cells
we looked at the properties of hydroxylated sterols as a precursor for
steroid production. In :intact cells exogenous substrates have to pass
through several membranes to reach the mitochondrion, where the side-chain
cleavage occurs. In order to eliminate possible effects on transport
through membranes, we also used damaged bovine adrenal mitochondria to
investigate the conversion of hydroxylated sterols. We also studied the
effects of hydroxylated sterols on short-term stimuli of steroid production. Either the total cell suspension (Chapters 4 and 5) or
suspensions containing largely glomerulosa cells or fasciculata/reticularis
cells (Chapter 6) were used in these studies. Before exerting their action, steroid hormones have to be taken up by
target cells and bound to receptors. It is commonly assumed that steroid
hormones diffuse passively through the cell membrane, although there is
some evidence for a mediated uptake rnechanism (Rao, 1981). In the rat,
corticosterone is the main glucocorticoid and the liver is an important
target organ. To study possible effects of hydroxylated sterols on steroid
uptake we used the uptake of corticosterone in isolated rat liver cells as
a model system (Chapter 7). In addition the effects of several sterols on
the uptake and conversion of pregnenolone in isolated rat adrenal cells
were investigated (Chapter 8) . As will be discussed in Cllapter 3, the method of cell isolation used
for the rat adrenal can be applied to the human fetal adrenal, yielding
viable cells. Also the method of separating cells of the fetal zone from
those of the definitive zone by means of density gradient centrifugation
can be used. With these cells the properties of hydroxylated sterols as
steroid precursors were studied ( Chapter 9) .
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
0
References
0
Citations
NaN
KQI