Dopamine D2 receptor mRNA measured in serial sections of the rat anterior pituitary

Dopamine D2 receptors (D2-Rs) on lactotrophs in the pituitary gland are tar gets for dopamine to inhibit prolactin synthesis and release. The aim of ou r study was to examine if subpopulations of cells in the anterior pituitary that respond differently to dopamine show different pattern of D2-R mRNA e xpression. Therefore, we have used quantitative in situ hybridization techn ique to study the localisation of D2-R mRNA in the rat adenohypophysis. Pit uitary tissue was obtained from mature and 18 days old rats. Riboprobe was transcribed from rat pituitary cDNA clone encoding D2-R and hybridized in s itu with the serial sections of the pituitaries. Our results show that, alt hough the anterior lobe of the pituitary gland contains a variety of cell t ypes distributed in clusters, D2-R mRNA is relatively evenly distributed th rough the adenohypophysis. Level of expression of D2-R mRNA in the pituitar y is slightly higher in mature than in young rats.