15. 4. 1977

Prepubertal unresponsiveness of

Speeialia

androgen-dependent mierosomal enzyme activities* of rat liver towards exogenous testosterone

Day of life

Male rats Untreated

ZP-3fl-Hydroxysteroid dehydrogenase

15 20 25 30 75

26 38 34 45 323

20-Ketoreductase

15 20 25 30 75

7.8 -L 1.1 8.3 =~ 0.6 28.0 ~ 3.0

30

12 ~ 4

Seminal vesicles**

541

i Jc ~_ -~ i46

4.6 ~

Female rats Untreated

Treated 6 5 8 3

42 28 31 38

0.4

J- 7 • 13 • 10 ]_ 6

5.1 •

5.4 4.= 0.9

0.9

4.0 -~ 0.7 6.6 • 6.4 • 125

1.1 1.4

27 35 26 45 48 3.9 4.2 8.6 9.1 8.0

~_ • ~_ ~• =l~_ -c ~ •

8 6 8 6 15 1.2 0.7 0.6 1.3 1.2

Treated 45 35 26 56 3.9 3.7 7.1 6.7

::L 7 ::: 8 ::z 8 _-t= 3 • J= J: •

t.5 1.3 1.3 1.3

:3_ 17

*nmol • min -* g-i liver wet weight; means -: SD; in each group liver was pooled from 8 rats, 6 determinations per pool. **Wet weight, rag.

v a l u e s w a s d e t e r m i n e d b y S t u d e n t ' s t - t e s t . T h e d e g r e e of s i g n i f i c a n c e w a s s e t a t p < 0.001. Results and discussion. U p t o d a y 30 of life, t h e a c t i v i t i e s of 3 4 - 3 f i - h y d r o x y s t e r o i d d e h y d r o g e n a s e and 20-ketoreductase of testosterone-treated animals did not show any substantial deviation from the normal developmental c o u r s e (table). I n c o n t r a s t , t h e a c t i v i t y of 3c~-hydrox y s t e r o i d d e h y d r o g e n a s e r e s p o n d e d in a b i p h a s i c m a n n e r in b o t h s e x e s ; w i t h i n 5 d a y s of a d m i n i s t r a t i o n , a 3fold increase had occurred and was followed by a further rise

10 11 12 13

A. K. Roy, Endocrinology 92, 957 (1973). A . J . l?Aseufeld, R. Aten, M. Weinberger, G. Haselbacher, K. Halpern and L. Krakoff, Science 191, 862 (1976). A. K. Roy, B. S. Milin and D. M. McMinn, l{iochim, biophys. Acta 35d, 213 (1974). W . I . P . Mainwaring, F.. K. Sytucs and S. J. Higgins, 13ioehem. J. 156, 129 (1976).

i n a c t i v i t y b e t w e e n d a y 25 a n d 30 w h e n t h e leveI n o r m a l l y f o u n d in m a t u r e m a l e r a t s w a s r e a c h e d (figure). N o sign i f i c a n t d i f f e r e n c e s in t h e p r o t e i n c o n t e n t of t h e m i c r o s o m a l f r a c t i o n s w e r e n o t e d f o r a n y of t h e g r o u p s , a n d t h u s t h e e x p r e s s i o n of t h e e n z y m e a c t i v i t i e s in t e r m s o f w e t w e i g h t r e f l e c t s c h a n g e s i n t h e ' s p e c i f i c ' a c t i v i t i e s of these enzymes. T h e r e s u l t s of t h i s i n v e s t i g a t i o n i n d i c a t e t h a t t h e s e x u a l i n d i f f e r e n c e in t h e p r e p u b e r t a l p h a s e of e n z y m e a c t i v i t y o n t o g e n e s i s is p a r t l y t h e r e s u l t of l o w a n d r o g e n leveIs a n d p a r t l y t h e r e s u l t of u n r e s p o n s i v e n e s s t o a n d r o g e n s . T h e r e f r a c t o r i n e s s of p r e p u b e r t a l l i v e r t o s e x u a l h o r m o n e s h a s also b e e n o b s e r v e d f o r t h e a n d r o g e n - d e p e n d e n t s y n t h e s i s of % , > g l o b u l i n i~ a n d for t h e o e s t r o g e n - d e p e n d e n t s y n t h e s i s of ' r e n i n s u b s t r a t e ' ~1. I t is p o s s i b l e t h a t a n d r o g e n u n r e s p o n s i v e n e s s m a y b e d u e t o t h e l a c k of a n d r o g e n r e c e p t o r s . H o w e v e r , t h e e x i s t e n c e of s u c h r e c e p t o r s in t h e l i v e r of t h e m a t u r e r a t r e m a i n s c o n t r o v e r s i a l I~,1a

Catecholamine-sensitive adenylate cyclase of h u m a n fat cell ghosts. Inhibition of catecholamine stimulation by phenylephrine H . K a t h e r , B. V o g t a n d B. S i m o n

Klinisches lrnstitut /r Herzin/arkt/orschung an der M e d i z i n i s c h e n Usiversitdtshlinik, D - 6 9 Heidelberg (Federal Republic of Germany, B R D ) , 18 October 1976 Summary. The alpha-adrenergic agonist phenylephrine (up to 1 mM) did not affect basal and NaF-stimulated adenylate c y c l a s e a c t i v i t i e s of h u m a n f a t cell g h o s t s , b u t c a u s e d a d o s e - d e p e n d e n t i n h i b i t i o n of c A M P f o r m a t i o n in t h e p r e s e n c e of c a t e c h o l a m i n e s . C a t e c h o l a m i n e s a r e t h o u g h t to a c t v i a a l p h a - a n d b e t a a d r e n e r g i c r e c e p t o r s i t e s I 4. I t h a s b e e n s u g g e s t e d t h a t both receptor types are coupled to the membrane-bound a d e n y l a t e c y c l a s e s y s t e m in a d i p o c y t e s ~ 9. A c c o r d i n g t o t h i s c o n c e p t , b i n d i n g of c a t e c h o l a m i n e s to t h e b e t a a d r e n e r g i e r e c e p t o r l e a d s t o a n a c t i v a t i o n of t h e e n z y m e s y s t e m , w h e r e a s i n t e r a c t i o n w i t h a l p h a - a d r e n e r g i c rec e p t o r s i t e s is a s s o c i a t e d w i t h i n h i b i t i o n of c A M P f o r mation. We have previously shown that the human fat cell a d e n y l a t e c y c l a s e is c o u p l e d t o b e t a - a d r e n e r g i c r e c e p t o r s 1~ I n a n a t t e m p t t o c l a r i f y t h e role of a l p h a a d r e n e r g i c s t i m u l a t i o n , t h e e f f e c t s of p h e n y l e p h r i n e - a n a l p h a - a d r e n e r g i c a g o n i s t - o n t h e h u m a n f a t cell a d e n y l a t e cyclase activity were tested.

1 2 3 4 5 6 7 8 9 10

R. I t, Ahlquist, Am. J. Physiol. 153, 586 (1948). E . W . Sutherland, in : Pharmacology of cholinergic and adrenergic transmission, p. 317. Ed. G. B. Koelle, W. W. Douglas and A. Carlson. Pergamon, Oxford 1.965. R . F . Furchgott, Fed. Proc. 29, 1352 (1970). J. Ashmore, Fed. Proc. 29, 1.386 (1970). G . A . Robison, P. E. Langley and T. W. Burns, Biochem. Pharmac. 21, 589 (1972). L.A. Ostman and S. Efendic, Acta reed. scand. /87, 471 (1970). J . R . Turtle and D. M. Kipnis, Biochem. biophys. Res. Commun. 28, 797 (1967). G . A . Robison and E. W. Sutherland, Circulation Res. 26 and 27, Suppl. 1, 147 (1970). T . W . Burns and P. E. Langley, J. Cyc. Nucl. Res. 7,321 (I975). H. Kather, B. Vogt and B. Simon, Klin. Wschr., submitted for publication (1976).

542

Specialia

Methods. Biopsies of s.c. adipose tissue were o b t a i n e d f r o m 8 p a t i e n t s u n d e r g o i n g surgical t r e a t m e n t . T h e p a t i e n t s were o p e r a t e d a f t e r a n o v e r n i g h t fast. A n e s t h e s i a was ind u c e d w i t h a s h o r t a c t i n g b a r b i t u r a t e a~ld m a i n t a i n e d w i t h h a l o t h a n e , n i t r o u s oxide a n d oxygen. T h e biopsies were u s u a l l y o b t a i n e d a f t e r t h e skin incision a t t h e s t a r t of t h e o p e r a t i o n . Adipose tissues a n d f a t cell g h o s t s were p r e p a r e d e s s e n t i a l l y a c c o r d i n g t o R o d b e l l ~1 as d e s c r i b e d p r e v i o u s l y 1~ T h e a d e n y l a t e cyclase a c t i v i t y of f a t cell g h o s t s was d e t e r m i n e d a c c o r d i n g to S a l o m o n e t al. 12. D a t a are g i v e n as n m o l e s of c A M P f o r m e d p e r m g p r o t e i n p e r 15 min. S t a t i s t i c a l a n a l y s i s was b y t h e W i l c o x o n - t e s t for p a i r e d samples. Tile p r o t e i n c o n t e n t of t h e s a m p l e s was d e t e r m i n e d a c c o r d i n g t o L o w r y et al. ~3 u s i n g b o v i n e s e r u m a l b u m i n as s t a n d a r d . Materials. (e-~aP) A T P (2-6 c o u n t s / m m o l e ) a n d cyclic (~H) A M P (27 c o u n t s / m m o l e ) were p u r c h a s e d f r o m R a d i o c h e m i c a l C e n t r e A m e r s h a m Bucks, E n g l a n d . E p i n e p h r i n e , i s o p r o t e r e n o l a n d p h e n y l e p h r i n e were o b t a i n e d f r o m B o e h r i n g e r & S6hne, I n g e l h e i m a m R h e i n ( B R D ) .

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Catecholamine-sensitive adenylate cyclase of human fat cell ghosts. Inhibition of catecholamine stimulation by phenylephrine.

15. 4. 1977 Prepubertal unresponsiveness of Speeialia androgen-dependent mierosomal enzyme activities* of rat liver towards exogenous testosterone...
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