To clarify the molecular basis for the prostaglandin (PG) mediated effects in adipose cells at various stages of their development, expression of mRNAs encoding receptors specific for prostaglandin E2, F(2α) and I2 (i.e. EP, FP, and IP receptors) was investigated in differentiating clonal Ob1771 pre-adipocytes, as well as in mouse primary adipose precursor cells and mature adipocytes. We have further characterized the differential expression of mRNAs encoding three subtypes of the EP receptor, i.e. EP1, EP3, and EP4, and examined the expression of mRNAs encoding the three isoforms (α, β, and γ) of the EP3 receptor. Altogether the results show that the expression of IP, FP, EP1, and EP4 receptor mRNAs was considerably more pronounced in pre-adipose cells than in adipose cells, mRNAs encoding the α, β, and γ isoforms of the EP3 receptor were all exclusively expressed in freshly isolated mature adipocytes. These data may indicate that PGI2, PGF(2α), and PGE2 may interact directly with specific receptors in pre-adipose cells, whose transduction mechanisms are known to affect maturation related changes. In mature adipocytes, however, the equipment of mRNAs encoding the EP3 receptor isoforms is in agreement with the well known effect of PGE2 on adenylate cyclase and lipolysis in mature adipocytes. Copyright (C) 1999 Elsevier Science Inc.