Differences in retinoid levels and metabolism among gastropod lineages: Imposex-susceptible gastropods lack the ability to store retinoids in the form of retinyl esters.

Highlights: [•] Until recently, the presence of an elaborated retinoid system was believed to be a chordate/vertebrate novelty. [•] Patella depressa has the capacity to store retinoids in the form of inactive retinyl esters. [•] The imposex-susceptible species Nucella lapillus and Nassarius reticulatus lacked detectable amounts of retinol or retinyl esters. [•] An exposure test with N. lapillus confirmed that this species is not able to synthesize retinyl esters in vivo. [•] The incapacity to inactivate retinoid precursors might negatively affect retinoid signaling homeostasis.