Wikipedia
Adenylthiomethylpentose is a sulfur-containing nucleoside that was formerly known as vitamin L.
In 1912, an adenine nucleoside was isolated by Hunter et al. from yeast that were grown without phosphorus or sulfur. Later that substance was shown by Levene and Sobotkal to be adenylthiomethylpentose.
In 1936, W. Nakahara et al. did experiments on rats that suggested that vitamin L deficiency inhibits the ability of rats to lactate. In 1942 they identified vitamin L to be adenylthiomethylpentose. Later studies by Folley et al refuted Nakahara's claims and demonstrated that L2 is not necessary for lactation and thus L is not considered a vitamin today.
Hecht found in 1937 that the body temperature of rabbits, cats and guinea pigs were lowered by 1 to 2 degrees after he gave them adenylthiomethylpentose at a dose of 0.2 g/kg. Kühn et al. replicated this in guinea pigs in 1941.