Visualization of gene expression of prolactin receptors (PRL-R) by in situ hybridization, in Typhlonectes compressicaudus, a gymnophionan amphibian

The expression of the short and long forms of prolactin receptors (PRL-R) mRNA was studied in various types of tissues from Typhlonectes compressicaudus, an amphibian, by quantitative in situ hybridization. Both forms were expressed in all the types of tissues studied. In the liver, small intestine and hypophysis, the mRNA coding for the short form of PRL-R was more strongly expressed than the mRNA coding for the long form and vice-versa for the stomach, spleen and kidneys. In the female liver, quantification showed a higher value of mRNA expression mid-way through pregnancy than during the sexual inactivity period. This result was found to be correlated with the reserve function of the liver. In the kidney and small intestine, the presence of PRL-R was correlated with the hydromineral function. A comparison with certain mammals was also established. These results confirm the ubiquity of PRL effects on metabolic regulation, and suggest a phylogenic conservation of its receptors.