** Shares in Novo Nordisk NOVOb.CO fall around 2% after it agreed to buy drug developer Akero Therapeutics AKRO.O for up to $5.2 billion
** Novo says it will buy Akero for $4.7 billion in cash, along with $500 million contingent upon meeting certain milestones
** Nordnet analyst Per Hansen says the acquisition is costly and shows Novo is "still building on the breadth of its portfolio"
** "The share price reaction may be a sign of something that is not mentioned in the announcement from Novo Nordisk: the share buyback," he adds
** Novo's Danish peer Zealand Pharma ZELA.CO is down about 2.4%; Hansen notes Akero is active in treatment of fatty liver disease, like Zealand Pharma
(Reporting by Elviira Luoma)
((Elviira.luoma@thomsonreuters.com))