385 Abnormalities in Growth Hormone Secretion After Cranial Irradiation in Primates

Abstract

~e i . & C a r d i o . Res. I n s t . , Univ. C a l i f . , S a n F r a n c i s c o .To e x a m i n e t h e o n t o g e n y a n d r e g u l a t i o n o f CBG i n t h e p e r i n a t a l p e r i o d , we d e t e r m i n e d p l a s m a c o r t i s o l b i n d i n g c a p a c i t y u s i n g a c h a r c o a l a b s o r p t i o n a s s a y .CBG c a p a ci t y i n c r e a s e d p r o g r e s s i v e l y f r o m 1 . 6 p g / d l a t 75 d a y s t o 7 . 1 u g / d l a t 1 4 1 d a y s ( n = 2 4 9 ) , w i t h t h e g r e a t e s t i n c r e a s e f r o m 1 2 1 d a y s t o t e r m .T h e r e was a s i m i l a r i n c r e a s e i n CBG ( + 4 1 . 1 % ) a n d t o t a l p r o t e i n s ( + 3 6 . 7 % ) i n 6 f e t u s e s d u r i n g t h e 4-6 d a y s b e f o r e s p o n t a n e o u s d e l i ve r y .A f t e r b i r t h , b o t h CBG a n d p r o t e i n s d e c r e a s e d d u ri n g t h e f i r s t h a l f d a y ; t h e r e a f t e r CBG d e c r e a s e d ( t + = 5 d a y s ) t o 1 . 0 p g / d l a t 1 4 d a y s w h i l e p r o t e i n s d i d n o t c h a n g e . I n 7 f e t u s e s w i t h l o s s o f p i t u i t a r y f u n c t i o n t h e r e was n o i n c r e a s e i n C B G d u r i n g t h e 22-35 d a y s a ft e r s u r g e r y . I n f u s i o n s o f h y d r o c o r t i s o n e f o r 2 d a y s , e s t r a d i o l f o r 5 d a y s , p r o l a c t i n f o r 5-8 d a y s a n d ACTH f o r 3 d a y s t o i n t a c t f e t u s e s d i d n o t a f f e c t CBG l e v e l s . We, c o n c l u d e t h a t t h e p i t u i t a r y c o n t r o l s t h e m a j o r i n c r e a s e i n CBG a f t e r 1 2 1 d a y s ; t h e r e i s a n a d d i t i o n a l p r e p a r t u m i n c r e a s e i n a l l s e r u m p r o t e i n s w i t h l a b o r . The p i t u i t a r y h o r m o n e ( s ) w h i c h s t i m u l a t e C B G p r o d u c t i o n a r e n o t i d e n t i f i e d , b u t t h i s h o r m o n a l i n f l u e n c e a p p a re n t l y c e a s e s w i t h b i r t h .