Effects of prolactin and growth hormone on protein synthesis in larval and adult frogs (Rana pipiens).

Abstract

AbstractFrogs and tadpoles (Rana pipiens) were treated with mammalian prolactin or growth hormone for several days, then injected with 14C‐leucine. Fourteen to sixteen hours later the animals were killed and the amount of label incorporated into protein of muscle, liver, and gut was measured.Growth hormone stimulated the incorporation of leucine into protein of gastroenemius muscle and small intestine, but not liver, of the frog. Prolactin had no effect on amino acid incorporation in any of these tissues in the frog. Prolactin stimulated the incorporation of leucine into protein of tail muscle, intestine and liver of tadpoles. The effect was not entirely consistent, and was of a smaller magnitude than was expected on the basis of the growth‐promoting effects of prolactin in tadpoles. This problem is discussed. Growth hormone had no effect on protein synthesis in any of these tissues in any experiment.