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Prolactin and tadpole metamorphosis evidence of prolactin receptors in premetamorphic Rana catesbeiana liver and tail fin

1980; Elsevier BV; Volume: 17; Issue: 3 Linguagem: Inglês

10.1016/0303-7207(80)90109-4

1872-8057

Frances E. Carr, Randal C. Jaffe,

Adipose Tissue and Metabolism

The binding characteristics of ovine prolactin (oPRL) to a participate fraction from liver and tail fin of Rana catesbeiana tadpoles were studied. The specific binding of [125I] oPRL to both tissues was found to be a saturable process with a single class of binding sites in each tissue. Although the dissociation constants were similar for each tissue, the tail fin demonstrated a 10-fold higher binding capacity than the liver tissue. Pretreatment of the liver and tail fin particulate fractions with degradative enzymes revealed that trypsin and phospholipase C reduced the subsequent specific [125I] oPRL binding in both tissues. However, neuraminidase treatment decreased the prolactin binding in the liver while having no effect on the tail fin. The binding of prolactin to the amphibian tissues was found to be specific for prolactin and growth hormones. [125I]oPRL binding to both tissues was a reversible process although the dissociation rate was faster for the tail fin than for the liver. Therefore, prolactin receptors are associated with both a prolactin responsive tissue, the tail, and an unresponsive tissue, the liver, in the tadpole.