Effects of oral caffeine intubation on bones in protein-energy malnourished newborn rats.

Lactating dams with 8 suckling pups were fed either a 6% or a 20% protein diet from the birth of the pups to day 15. The pups were divided into caffeine and noncaffeine groups. Every other day between days 3 and 13, pups were either intubated with caffeine (1 mg/100 mg) dissolved in 0.1 ml physiological saline solution, or 0.1 ml saline solution as a control. On day 15, mandible and long bone weights, DNA, protein and calcium contents, collagen synthesis and 45Ca uptake in these bones of the pups were studied. Nutritional factors exercised consistent effects on all the studied parameters, but there was no difference in effects attributable to caffeine intubation, except the increased collagen synthesis in the long bones of the group with 6% protein diet with caffeine as compared to noncaffeine members of the same dietary group. We concluded that the direct administration of a relatively small amount of caffeine to newborns causes minor effects on bone development under certain nutritional conditions.