Microtubules from pancreas have been isolated and estimated. It was found that rats fed with lysine and threonine deficient diet have profoundly lowered levels of microtubules as compared to rats fed either with lysine and threonine supplemented diet or a casein diet at 20% protein level, implicating the role of dietary protein in microtubule assembly. Levels of microtubules in turn may influence the turnover of phosphatidyl inositol as well as release of insulin from pancreas.