Tissue-specific variation in expression of prolactin receptor gene subtypes in hypergravity-exposed rats

Prolactin (PRL) effects are mediated by membrane receptors (PRLR) of which the long (PRLR-L) and short form (PRLR-S) predominate. Our objective was to compare the distribution pattern of PRLR-L and PRLR-S transcripts and their ratio in adipose (AD), liver (LV), mammary (MG) and pituitary (PG) tissues of stationary (SC, n = 8) and hypergravity (HG, n = 8) exposed periparturient rats. Pregnant rats were exposed to 2 g force from day 11 of gestation (G11) through post partum day 1 (P1). PRLR-L mRNA expression compared to PRLR-S was greater (P < 0.001) in AD, MG and PG but was lower (P < 0.001) in LV in both HG and SC animals at P1. The ratio of PRLR-L/PRLR-S mRNA in the AD, LV, MG and PG was not different between HG and SC rats. In summary, these data reveal that the hypergravity-induced downregulation of PRLR is not directly triggered by deranged distribution of PRLR isoforms.