▁stress - related ▁dise ases ▁in ▁the ▁long ▁term . ▁ ▁I G F - 1 ▁signal ing ▁▁ ▁is ▁a ▁pe pt ide ▁and ▁ne uro t roph ic ▁factor ▁that ▁medi ates ▁some ▁of ▁the ▁effects ▁of ▁growth ▁h orm one ; ▁ ▁I G F - 1 ▁el ic its ▁its ▁phys i ological ▁effects ▁by ▁binding ▁to ▁a ▁specific ▁re ceptor ▁ty ros ine ▁kin ase , ▁the ▁I G F - 1 ▁re ceptor , ▁to ▁control ▁t issue ▁growth ▁and ▁rem od eling . ▁In ▁the ▁brain , ▁I G F - 1 ▁functions ▁as ▁a ▁ne uro t roph ic ▁factor ▁that , ▁like ▁, ▁plays ▁a ▁significant ▁role ▁in ▁cogn ition , ▁ne uro gen esis , ▁and ▁neur onal ▁surv ival . ▁Phys ical ▁activity ▁is ▁associated ▁with ▁increased ▁levels ▁of ▁I G F - 1 ▁in ▁blood ▁ser um , ▁which ▁is ▁known ▁to ▁contribute ▁to ▁ne uro pl astic ity ▁in ▁the ▁brain ▁due ▁to ▁its ▁capacity ▁to ▁cross ▁the ▁blood – bra in ▁bar rier ▁and ▁blood – c ere bro sp inal ▁fluid ▁bar rier ; ▁consequ ently , ▁one ▁review ▁noted ▁that ▁I G F - 1 ▁is ▁a ▁key ▁medi ator ▁of ▁exercise - indu ced ▁adult ▁ne uro gen esis , ▁while ▁a ▁second ▁review ▁character ized ▁it ▁as ▁a ▁factor ▁which ▁links ▁" body ▁fit ness " ▁with ▁" bra in ▁fit ness ". ▁ ▁The ▁amount ▁of ▁I G F - 1 ▁released ▁into ▁blood