"Through their discoveries, Rothman, Schekman and Südhof have revealed the exquisitely precise control system for the transport and delivery of cellular cargo," the Nobel Assembly at Sweden's Karolinska Institute said in a statement when awarding the prize.

For example, their research sheds light on how insulin is manufactured and released into the blood at the right place at the right time, the Nobel committee said.

It said the laureates' work deepened understanding of how disruptions in the transport of cells contribute to neurological diseases, diabetes and immunological disorders.

All three laureates work at US universities. Südhof, 57, joined Stanford University in 2008, Rothman, 62, is a professor at Yale University, and Schekman, 64, is at the University of Berkeley, California.

The Nobel Prize in Physiology or Medicine is the first of the Nobel prizes awarded each year. This week will also see the awarding of the Nobel Prizes for physics on Tuesday, and for chemistry on Wednesday.

The Swedish Academy, which makes the annual decision on who receives the Literature Prize, announced on Monday that the winner will be disclosed on Thursday, as had been widely expected.

Nobel highlight

The season culminates in the awarding of the Nobel Peace Price on Friday, October 11, in Oslo, Norway. A record 259 nominations have been submitted for this year's prize.

Among the people widely mentioned as possible laureates is Malala Yousafzai, the Pakistani teenager who survived being shot in the head last year by the Taliban for championing education for girls.

Last year's winner was not a person, but an entity: the European Union, which received the prize in recognition of its achievements in bringing about reconciliation and integration in Europe.

Extra prize

The Nobel season will end on October 14 with the presentation of the Nobel Memorial Prize in Economic Sciences, a prize not originally established by the will of the award's founder, Alfred Nobel. This prize was introduced in 1968 by the Swedish central bank, the Sveriges Riksbank, in memory of Nobel, an industrialist who invented dynamite.

All the prizes are traditionally presented to the winners in a ceremony in Stockholm on December 10, the anniversary of the death of Alfred Nobel (1833-1896). Laureates receive a diploma, medal and around eight million Swedish kronor (920,000 euros, $1.25 million).

The Nobel Prizes were established in Nobel's will in 1895 and are widely seen as his attempt to be remembered by posterity for something more than an invention that has caused so much destruction. The prizes in physics, chemistry, physiology or medicine, literature and peace were first awarded in 1901.

tj/hc (AFP, AP, Reuters)