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Melanin-concentrating hormone in lower vertebrates: Models for mammalian studies
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MELANIN-CONCENTRATING HORMONE IN ~ R V E R T E B R A T E S :
MODELS FOR MAMMALIAN
STUDIES. B.I. BAKER, School of Biological Sciences, Bath University, Bath BA2 7AY, UK.
Vertebrates all possess homologous hormones whose function may change during evolution. An obscure (although not necessarily unimportant) hormone in mammals may be discovered because its hon~logue has a striking effect in lower vertebrates. This is the case for MCH which, in teleosts, causes pallor, antagonizes MSH-induced melanin dispersion in melanophores, depresses the secretion of MSH from the pituitary gland and potentiates the effect of noradrenalin on melanophores. It also depresses CRF and ACTH release, thus modulating the response of fish to stress. In teleosts, MCH is contained in neurohypophysial fibres and in fibres which project up into the brain. In m~Lmnals, abundant MCH perikarya occur in the lateral hypothalamus and fibres project throughout the brain (excepting the cerebellum) and to the spinal cord. A few fibres extend to the median eminence and neural lobe. Its widespread distribution suggests that MCH has a neuromodulatory role associated with diverse functions. A few clues and potential functions of ~ H in mammals will be reviewed.
ORGANIZATION AND REGUI,ATION OF THE GENE ENCODING F H R F a m i d c RET,ATFJ) PEPTIDES IN THE BRAIN OF I.YMNAEA ,¢~TAGNAL-rS.
J . F . BURKE, S . E . SAUNDERS, E. KELLETT, K. BRIGHT, N. SANTAMA. P.R. BENJAMIN BJo]ngica] Sciences, University o f S u s s e x , F a ] m e r , l l r J g h ? o n BN1 qQG. l ) . g , The pond s n a i l Lymnaea s t a g n a I i . e , h a s b e e n shown by b i n c : h e m J c a ] a n a ] y s i s io contain the neuropeptides FMRFamide, GDPFLRFamide a n d S D P F L R F a m i d e . We a r e interested i n how t h e s e neuropeptides arc encoded and processed, To do t h i s we h a v e c l o n e d a n d s e q u e n c e d t h e g e n e ( s ) e n c o d i n g t l l e s e p e p t i d e . s . Two eDNA ( : ] o n e s , DI a n d D'I h a v e b e e n c l o n e d anti s e q u e n c e d (].ina(;re et ~1., J. Neurosci., ] 9 9 0 ) anti s h o w n t o e n e n d e t w n ( ; n p i e s o f F l , R F a m i d e a n d hint," c o p i e s o f Ft4RFamide. Tile c l o n e 93 w a s u s e d t o s c r e e e n a Lymn,~ea g e n e r a l ( ]ibrary t o f i n d t h e Met s t a r i c o d o n a s t h e (-I)NA (:]nnt~s w e r e n n i full length. A 7 . 0 kb g e n o m i c c l o n e was i s o l a t e d and sequenced. The g e n e r a l ( a n d eDNA s e q u ( ' n e e s w e r e t h e n c o m p a r e d anti f r o m t h i s i t was p t ) s s i b ] e lo predict potential RNA s p l i c e sites. The p o ] y m e r a s e c h a i n r e a e t i n n (PCR) m e t h o d w a s u s e d on DNA made f r o m a eDNA library t o a m p l i f y t i l e 5 ' a n d 3 ' e n d s t o c o m p l e t e t i l e eDNA s e q u e n c e . The products were ana]ysed and found tn fail i n t : o tArt:c; d i f f e r e n t (:lasses. One g r o u p e n c o d e d F L R F a m l d e a n d FMRFamide. Tile se, c o n d c o n s i s t e d of sequence 5' to the prevJous]y iso]ated ( : ] o n e s anti t h e t h i r d Lcroap e n c o d e d GI)PT¢l,RFamid(~. Together with in situ hybridization data, this suggests that regulation o¢ expression of the peptides m~,V b c a l 1 h e ] e v e ] o f RNA s p l i c i n g . A.M.T. Linacre et el. ( 1 9 9 0 ) J . X e u r o s , , - i . 1.0. 4 1 2 - 4 1 9 .
MELANIN-CONCENTRATING HORMONE IN ~ R V E R T E B R A T E S :
MODELS FOR MAMMALIAN
STUDIES. B.I. BAKER, School of Biological Sciences, Bath University, Bath BA2 7AY, UK.
Vertebrates all possess homologous hormones whose function may change during evolution. An obscure (although not necessarily unimportant) hormone in mammals may be discovered because its hon~logue has a striking effect in lower vertebrates. This is the case for MCH which, in teleosts, causes pallor, antagonizes MSH-induced melanin dispersion in melanophores, depresses the secretion of MSH from the pituitary gland and potentiates the effect of noradrenalin on melanophores. It also depresses CRF and ACTH release, thus modulating the response of fish to stress. In teleosts, MCH is contained in neurohypophysial fibres and in fibres which project up into the brain. In m~Lmnals, abundant MCH perikarya occur in the lateral hypothalamus and fibres project throughout the brain (excepting the cerebellum) and to the spinal cord. A few fibres extend to the median eminence and neural lobe. Its widespread distribution suggests that MCH has a neuromodulatory role associated with diverse functions. A few clues and potential functions of ~ H in mammals will be reviewed.
ORGANIZATION AND REGUI,ATION OF THE GENE ENCODING F H R F a m i d c RET,ATFJ) PEPTIDES IN THE BRAIN OF I.YMNAEA ,¢~TAGNAL-rS.
J . F . BURKE, S . E . SAUNDERS, E. KELLETT, K. BRIGHT, N. SANTAMA. P.R. BENJAMIN BJo]ngica] Sciences, University o f S u s s e x , F a ] m e r , l l r J g h ? o n BN1 qQG. l ) . g , The pond s n a i l Lymnaea s t a g n a I i . e , h a s b e e n shown by b i n c : h e m J c a ] a n a ] y s i s io contain the neuropeptides FMRFamide, GDPFLRFamide a n d S D P F L R F a m i d e . We a r e interested i n how t h e s e neuropeptides arc encoded and processed, To do t h i s we h a v e c l o n e d a n d s e q u e n c e d t h e g e n e ( s ) e n c o d i n g t l l e s e p e p t i d e . s . Two eDNA ( : ] o n e s , DI a n d D'I h a v e b e e n c l o n e d anti s e q u e n c e d (].ina(;re et ~1., J. Neurosci., ] 9 9 0 ) anti s h o w n t o e n e n d e t w n ( ; n p i e s o f F l , R F a m i d e a n d hint," c o p i e s o f Ft4RFamide. Tile c l o n e 93 w a s u s e d t o s c r e e e n a Lymn,~ea g e n e r a l ( ]ibrary t o f i n d t h e Met s t a r i c o d o n a s t h e (-I)NA (:]nnt~s w e r e n n i full length. A 7 . 0 kb g e n o m i c c l o n e was i s o l a t e d and sequenced. The g e n e r a l ( a n d eDNA s e q u ( ' n e e s w e r e t h e n c o m p a r e d anti f r o m t h i s i t was p t ) s s i b ] e lo predict potential RNA s p l i c e sites. The p o ] y m e r a s e c h a i n r e a e t i n n (PCR) m e t h o d w a s u s e d on DNA made f r o m a eDNA library t o a m p l i f y t i l e 5 ' a n d 3 ' e n d s t o c o m p l e t e t i l e eDNA s e q u e n c e . The products were ana]ysed and found tn fail i n t : o tArt:c; d i f f e r e n t (:lasses. One g r o u p e n c o d e d F L R F a m l d e a n d FMRFamide. Tile se, c o n d c o n s i s t e d of sequence 5' to the prevJous]y iso]ated ( : ] o n e s anti t h e t h i r d Lcroap e n c o d e d GI)PT¢l,RFamid(~. Together with in situ hybridization data, this suggests that regulation o¢ expression of the peptides m~,V b c a l 1 h e ] e v e ] o f RNA s p l i c i n g . A.M.T. Linacre et el. ( 1 9 9 0 ) J . X e u r o s , , - i . 1.0. 4 1 2 - 4 1 9 .