PEPTI DES I N T HE B R AI N. T HE NE W E N D O C RI N O- L O G Y OF T HE NE UR O N Nobel Lect ure, 8 Dece mber, 1977 b y R O G E R G U I L L E M I N Laboratories for Neuroendocrinology T h e S al k I nstit ut e, S a n Di e g o, C alif or ni a, U. S. A. P A R T I A. The Existe nce of Brai n Peptides Co ntrolli ng Ade nohypophvsial F u nctio ns. Isolatio n a nd Characterizatio n of T heir Pri m ar y M olec ul ar Str uct ures I n t he early 1950s base d o n t he a nato mical observatio ns a n d p hysiological ex peri mentation fro m several gro u ps in the US A an d E uro pe, it beca me ab u n da ntl y clear t hat t he e n docri ne secretio ns of t he a nterior lobe of t he hy po p hysis- well k no w n by t he n to co ntrol all t he f u nctio ns of all t he target e n docri ne gla n ds, (t hyroi d, go na ds, a dre nal cortex) pl us t he overall so matic gro wth of the in divi d ual- were so meho w entirely reg ulate d by so me integra- tive mechanis m locate d in ne uronal ele ments of the ventral hy pothala m us (revie w Harris, 1955). Beca use of t he pec uliar a nato my of t he j u nctio nal regio n bet wee n ve ntral hy pot hala m us (floor of t he 3r d ve ntricle) a n d t he pare nc h y mal tiss ue of t he a nteri or l o be of t he pit uitar y ( Fi g. 1), t he mechanis ms involved in this hypothala mic control of adenohypophysial f unctions were best ex plaine d by pro posing the existence of so me secretory pro d uct(s) by so me ( u nc haracterize d) ne uro nal ele me nts of t he ve ntral h y p o t h a l a m u s , t h e p r o d u c t s o f w h i c h w o u l d s o m e h o w r e a c h t h e a de no hy po p hysis by t he pec uliar ca pillary vessels observe d as if to joi n t he floor of t he hy pot hala m us to t he pit uitary gla n d. T hat co nce pt was defi nitely ascertai ne d i n si m ple ex peri me nts usi ng co mbi ne d tiss ue c ult ures of frag me nts of t he pit uitary gla n d a n d of t he ve ntral hy po- thala m us ( G uille min an d Rosenberg, 1955). The search for characterizing the hypothetical hypothala mic hypophysiotropic factors starte d then. Si mple reasoning an d early che mical confir mation le d to the hy pothesis that these u nk no w n s ubsta nces wo ul d be s mall pe pti des. After several years of pilot st u dies i nvolvi ng bot h biology a n d relatively si m ple c he mistry i n several laboratories i n t he US A, E uro pe a n d Ja pa n, it beca me clear t hat c haracterizi ng these hypothala mic hypophysiotropic substances woul d be a challenge of (originally) uns us pecte d pro portions. Entirely novel bioassays wo ul d have to be de vise d for ro uti ne testi n g of a lar ge n u m ber of fractio ns ge nerate d b y t he c he mical p urificatio n sc he mes; m or e s o b eri n g still w as t h e r e ali z ati o n i n t h e early 1960s that enor mo us a mo unts of hy pothala mic frag ments (fro m sla ughter ho use a ni mals) wo ul d have to be obtai ne d to have available a s ufficie nt q ua ntity of starti ng material to atte m pt a mea ni ngf ul progra m of c he mical isolatio n. T he early pilot st u dies ha d i n dee d s ho w n t he hy pot hala mic s ub- 3 6 4 P e pti d es i n t h e Br ai n. T h e N e w E n d o cri n ol o g y of t h e N e ur o n l b Fi g. 1 : a) Dia gra m matic re prese ntatio n of t he pit uitar y gla n d a n d t he i n ner vatio n of t he neurohypophysis by nerve fibers fro m the n.paraventricularis ( P V N) an d supra-opticus (S O N). b) Localize d lesions in the hy pothala m us pro d uce changes in the pit uitary secretion of the vario us a denohy po physial hor mones (increase or decrease c) Diagra m matic re presentation of the hy pothala mo-hy po physial portal syste m. d) Photo microgra ph of the hy pothala mo-hy po physial portal syste m after injection with an o paq ue dye. e) Diagra m- matic re prese ntatio n of t he hy po p hysiotro pic area. f) C ha nges i n pit uitary secretio n of various a dpnohypophysial hor mones (increase , or d e cr e as e ). sta nces to be extre mely pote nt a n d, o n t he basis of si m ple ass u m ptio ns, to be prese nt i n eac h hy pot hala mic frag me nt o nly i n a fe w na nogra m q ua ntities. Esse ntially o ne, t he n t wo gro u ps of i nvestigators a p proac he d t he proble m wit h e n o u g h c o nsta nc y a n d res ol uti o n t o sta y wit h it f or t he te n years t hat it t o o k t o pr o vi de t he first of its defi niti ve s ol uti o n, i.e. t he pri mar y str uct ure of o ne of t he hy pot hala mic hy po p hysiotro pic factors: My o w n gro u p, t he n at Baylor College of Me dici ne i n Ho usto n, Texas ( wit h a n e piso de at t he Collège de Fra nce i n Paris), or ga nize d t he collectio n o ver se veral years of more t ha n 5 millio n s hee p brai ns, ha n dli n g i n t h e laboratory more than 50 tons of hy pot hala mic frag me nts. Sc hally a n d his collaborators, no w i n t he T ula ne 3 6 6 Physiology or Medicine 1977 U ni versit y Sc hool of Me dici ne i n Ne w Orlea ns, after he ha d left m y laborator y at Baylor, collecte d also very large n u mbers of porci ne hy pot hala mic frag- me nts. Late i n 1968, fro m 300,000 s hee p hy pot hala mi, B urg us a n d I isolate d 1.0 mg of t he first of t hese hy pot hala mic hy po p hysiotro pic pe pti des, t he thyrotro pin releasing factor ( T RF), the molec ule by which. the hy pothala m us reg ulates t hro ug h t he pit uitary t he f u nctio ns of t he t hyroi d gla n d ( G uille mi n et al., 1 9 6 2). T he follo wi ng year, after more tec h nical diffic ulties were overco me, we establis he d t he pri mary str uct ure of ovi ne T RF by mass s pectro metry as t hat of the deceivingly si m ple tri pe pti de p Gl u- His- Pro- N H 2 . T he material of porci ne ori gi n was s ho w n b y Sc hall y a n d his collaborators to be i de ntical. T he s y nt h eti c r e pli c at e, r a pi dl y a v ail a bl e i n u nli mit e d q u a ntiti es, w as s h o w n t o b e hi g hl y pote nt i n all verte brate s pecies a n d partic ularl y i n ma n; it is no w wi d el y us e d t hr o u g h o ut t h e w orl d i n a hi g hl y s e nsiti v e t est of pit uit ar y f u n cti o n a n d a n earl y mea ns of detectio n of pit uitar y t u mors i n ma n.