Different expression of the two dopaminergic D2 receptors, D2 415 and D2 444 , in two types of lactotroph each characterised by their response to dopamine, and modification of expression by sex steroids.
1991; Oxford University Press; Volume: 129; Issue: 2 Linguagem: Inglês
10.1210/endo-129-2-1101
ISSN1945-7170
AutoresLucy Anna Kukstas, Christine Domec, Lionel Bascles, Jacques Bonnet, Dany Verrier, Jean-Marc Israël, Jean‐Didier Vincent,
Tópico(s)Neuroscience and Neuropharmacology Research
ResumoDopamine inhibits prolactin liberation acting via the D2 type receptor. Two different electrophysiological responses to dopamine have been shown to characterise two types of lactotroph isolated from the lactating female rat. It is now known that differential splicing of the pre-messenger RNA coding for the D2 receptor leads to the production of two D2 subtypes D2415 and D2444. These subtypes differ in the region which is believed to be responsable for the binding of G proteins, and could thus lead to the activation of different intracellular second messenger systems. Here we show that the pre-messenger RNA for the D2 receptor is differentially spliced in such a way that the ratio D2415/D2444 is significantly different (2.91±0.6 vs 1.29+0.14) between two populations of lactotrophs, each enriched in cells showing one type of response to DA. We further show that the ratio D2415/D2444 can be changed by treatment of prolactin cells in primary culture with progesterone or testosterone. Estrogen did not change the ratio, but diminished the total amount of D2 cDNA. Regulation of differential splicing by sex steroids could provide a mechanism for modifying lactotroph responsiveness to DA in different physiological situations
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