Postnatal decline in pyridoxal phosphate and riboflavin. Accentuation by phototherapy.

Riboflavin is a cofactor in the conversion of pyridoxine (vitamin B6) to pyridoxal phosphate (PALP), an essential coenzyme in numerous metabolic pathways, including neurotransmitter synthesis. Riboflavin and pyridoxine are light sensitive in vitro, and conflicting results have been reported on the in vivo effects of phototherapy on riboflavin. We studied 25 full-term neonates receiving phototherapy and 16 healthy controls to evaluate their riboflavin and PALP status.