Effect of prolactin and androgen on the expression of the female-attracting pheromone silefrin in the abdominal gland of the newt, Cynops ensicauda

Silefrin is a sodefrin-like, female-attracting pheromone comprising 10 amin o acids that was isolated from the abdominal gland of the sword-tailed newt , Cynops ensicauda. Hormonal effects on the silefrin precursor mRNA express ion and silefrin content in the abdominal gland were investigated in the pr esent study by using Northern blot analysis and radioimmunoassay, respectiv ely. In the abdominal gland of newts treated with prolactin (PRL) plus test osterone propionate (TP), silefrin precursor mRNA expression was markedly e nhanced as compared with that in the newts injected with saline, PRL, or TP . Values for radioimmunoassayable silefrin content in the abdominal gland p aralleled those for the silefrin precursor mRNA levels. Moreover, silefrin precursor mRNA signals, as revealed by in situ hybridization, as well as st ainability of immunoreactive silefrin were much more intense in the epithel ial cells of the abdominal gland of the PRL-plus-TP-treated animals than in those of controls. We thus conclude that PRL and androgen are important fa ctors for enhancing silefrin synthesis.