Abstract.
We have investigated the individual roles of unmodified prolactin (U-PRL) and a mimic of phosphorylated PRL (S179D PRL) in mammary development. Recombinant versions of the PRLs were delivered to rats throughout pregnancy at a rate of 6 µg/24 h per rat and to non-pregnant females at a rate of 24 µg/24 h per rat. Measurement of progesterone, corticosterone, and estradiol showed no effect of the administered PRLs on the levels of these other mammotropic hormones. Histological and morphometric analysis showed U-PRL to cause mammary growth, whereas S179D PRL inhibited growth . Molecular analysis demonstrated decreased β-casein expression in the mammary glands of the U-PRL-treated animals at term and increased β-casein expression in the mammary glands of the S179D PRL-treated animals. Superior β-casein gene expression in response to S179D PRL versus U-PRL was confirmed in HC11 cells. We conclude that U-PRL is important for growth, whereas S179D PRL promotes at least one measure of differentiated function in the mammary gland.
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Kuo, B.C., Wu, W., Xu, X. et al. Pseudophosphorylated prolactin (S179D PRL) inhibits growth and promotes β-casein gene expression in the rat mammary gland. Cell Tissue Res 309, 429–437 (2002). https://doi.org/10.1007/s00441-002-0598-8
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DOI: https://doi.org/10.1007/s00441-002-0598-8