Role of D1- and D2-like receptors in age-specific regulation of juvenile hormone and 20-hydroxyecdysone levels by dopamine in Drosophila

In Drosophila females, the precursor of 20-hydroxyecdysone (20E), ecdysone, is synthesized in the ovary follicular cells. Juvenile hormone (JH) is synthesized de novo in the specialized endocrine gland, corpus allatum (CA); JH degradation is carried out by the enzymes synthesized in the fat body (FB). Earlier we have shown that in Drosophila females, dopamine up- or down-regulates 20E and JH levels depending on the developmental stage. The present study focuses on the role of D1- and D2-like receptors in the age-specific regulation of 20E and JH metabolism by dopamine. We show that in Drosophila melanogaster females D1- and D2-like receptor genes (DopR and DD2R accordingly) are expressed in CA and FB, but not in follicular cells. The level of DopR expression in CA is much higher in the young than in the mature females, whereas DD2R expression is much higher in the mature than in the young females. The DopR and DD2R expression patterns in FB are opposite to those observed in CA. In addition, we obtained data suggesting that the age-specific changes of DopR and DD2R expression in FB are under the control of 20E.