408 Characterization of high-affinity, low-capacity steroid binding proteins in human term placental cytosol

136s

407

BIOCHEMICAL Gabriele

AND ULTRASTRUCTURAL

Losa and Georges

ASPECTS

Maestroni,Laboratory

Cell membrane

constituents

and intimate

ultrastructural

involved

in phospholipid

topography,

or benign

were

carcinoma

a large amount of monosialoganglioside

trast to fibroadenomas whereas

where

acid

results

umole/lOO

protein.In

of intact tissue

lower intramembrane

revealed

of malignant

significant

epithelial

tivity of the methyltransferase membrane corded

phospholipids,

in malignant

Characterization placental

might

tissues

of

and suggest

high-affinity,

an increased

low-capacity

low-capacity

dexamethasone as

in

steroids

their were

Placentas

for 5

to

and

-

receptor progesterone

56

132

-

values The

coefficient

of

in

but

not protein

all

receptors

be

used

tissues,i.e. preparations

particle

densities

origin.

methylation

on plasma

An increased

ac-

and synthesis

particle

of

density

re-

of the plasma membrane.

binding

50 were

K.Pollow.

for

cytosols for

under

proteins

in

human

term

Abt.f.Experimentelle

fp=0.0447)

with than

4

S

under

for steroids estradiol

placental

salt for

K

140

fmol$s/mg

were

concentration

supplying

classes. could less

be than

of

5.07 male

protein

conditions.

other

receptor

cytosols

the

average

binding

low

first

Only

mean

those,

H-R1881-androgen

R5020 natural

were

the z

All

conditions.

The 219

estradiol,

experiments,

assay

protein,

R1881,

characterized.

specificity

receptor

should

labeled

were

stable.

fmol/mg

fetuses

protein.

fmoles/mg

levels

to

stability

female

androgens

components

placenta

b+e metabolically

169

higher

sedimentation only

vitro

supplying

fmoles/mg

term

steroids, in was

significant

cific

the methyltransfe-

Mainz.F.R.G. binding

human

found

protein

101

50

synthetic

for

binding

-

the n-

fracture

freeze

fluidity

steroid

accordance

cytosol.

High-affinity,

iy

carcino-

in benign

fit well with the low intramembrane

Endokrinologie,Universitatsfrauenklinik

gated

contrast,

an increased

H.J.Grill,A.Knichel,G.Schweikhart,T.Beck,B.Manz

well

that breast

carcinomas

cells than in those of benign 1,indicating

interaction

g in the latter tissues,

over the level measured

63.1 + 7.1 vs.10.4 + 3.4 fmole/min/mg membrane

409

revealed

was observed.In

increase

/CH

GM3 and to a less extent GM2 in con-

ranged 0.0-0.05

a 5-7 fold increase

a 6 fold activity

Locarno

in human tissues with diagno

only a scant GM3 band was detectable.In

(NANA)content

in carcinomas

rase I showed

fibroadenoma.Our

Pathology,6604

methylation,receptors

investigated

sed primary

IN HUMAN BREAST TISSUE.

CELLS

of Cellular

mas possess

acetylneuraminic

408

OF EPITHELIAL

:

In

detected, 10

lo-

M.

statistical-

fetuses

with

exhibited

binding 20

and$ogen

x

protein

complex The

investisynthetic

the

2.25

and as

of

site 50

the

fmoles/mg

was

cytosol

115.2 a spesamples

glucocorticoid protein,

undetectable.

Factors Regulating Activation of Rat Uterine Oestrogen Receptor L. Myatt, H.G. Elder 8 J.O. White. Institute of Obstetrics & Gynaecology, Hammersmith Hospital, Du Cane Rd, London,

1412.

The activation of rat uterine oestrogen receptor in a cytosol preparation containing phosphate buffer has been studied by assessment of oligo (dT)-cellulose Increasing time or temperature binding capability and ligand dissociation kinetics. of incubation with ligand promoted binding of (3H) oestradiol-labelled complexes to Addition of dithiothreitol (DTT) or ATP to cytosol increased olizo (dT)-cellulose. The rate of activation the rate of activation in a concentration-dependent manner. (assessed by oligo (dT)-cellulose bindine;) was decreased in the presence of molybdate (1OmM) which also blocked increases in activation rate due to addition of DTT or ATP. The changes in binding we observed were not matched by changes in the proportion of the fast and slow components (purportedly representing inactive and active receptor species) of the biphasic dissociation kinetics of the oestrogen receptor; this was in contrast to the chanp,es in proportions seen when cytosol was prepared in Tris buffers.