Blood pressure, plasma and pituitary prolactin levels and their responses to bromocriptine in the segregating F2 generation of the SHR/WKY hybrid.

Our previous study in the spontaneously hypertensive rat (SHR) and its normotensive control, the Wistar-Kyoto (WKY), had shown differences in plasma and pituitary prolactin (PRL) levels as well as in their responses to bromocriptine (BRC), a centrally acting dopaminergic agonist. The results provided evidence for a central dopaminergic deficiency in the SHR and suggested a possible genetic linkage between blood pressure (BP) and PRL and their responses to BRC in the SHR. To investigate this possibility further, we have repeated the experiment, using the same protocol, in the segregating F2 generation of the SHR/WKY hybrid which was classified according to BP into low, intermediate and high BP groups. The results from this study show that the differences between BP and PRL and their responses to BRC are similarly present in the three groups of the F2 generation. They provide further evidence that suggests a genetic linkage between BP and PRL in the SHR.