Localisation of GPR30, a novel G protein-coupled oestrogen receptor, suggests multiple functions in rodent brain and peripheral tissues

Recently, the G protein-coupled receptor GPR30 has been identified as a novel oestrogen receptor (ER). The distribution of the receptor has been thus far mapped only in the rat central nervous system. This study was undertaken to map the distribution of GPR30 in the mouse brain and rodent peripheral tissues. Immunohistochemistry using an antibody against GPR30 revealed high levels of GPR30 immunoreactivity (ir) in the forebrain (e.g. cortex, hypothalamus and hippocampus), specific nuclei of the midbrain (e.g. the pontine nuclei and locus coeruleus) and the trigeminal nuclei and cerebellum Purkinje layer of the hindbrain in the adult mouse brain. In the rat and mouse periphery, GPR30-ir was detected in the anterior, intermediate and neural lobe of the pituitary, adrenal medulla, renal pelvis and ovary. In situ hybridisation histochemistry using GPR30 riboprobes, revealed intense hybridisation signal for GPR30 in the paraventricular nucleus and supraoptic nucleus (SON) of the hypothalamus, anterior and intermediate lobe of the pituitary, adrenal medulla, renal pelvis and ovary of both rat and mouse. Double immunofluorescence revealed GPR30 was present in both oxytocin and vasopressin neurones of the paraventricular nucleus and SON of the rat and mouse brain. The distribution of GPR30 is distinct from the other traditional ERs and offers an additional way in which oestrogen may mediate its effects in numerous brain regions and endocrine systems in the rodent.