Metabolism of estrogens and androgens by scleractinian corals

Steroid metabolism in cnidarians: Insights from Nematostella vectensis

“…In previous studies, incubations of tritiated substrates with cnidarian homogenates have provided convincing evidence for the presence of diverse enzymes with the capability of metabolizing steroids, particularly enzymes with 17β-HSD activity (Gassman, 1992;Slattery et al, 1997;Tarrant et al, 2003). Of note, the endogenous functions of and substrates for these enzymes are unknown and the corresponding genes have not yet been identified.…”

“…Studies with alcyonacean corals ("soft" corals) from the Antarctic by Slattery and colleagues (1997) identified 5α-pregnane-3,20-dione, 5α-pregnane-3β-ol-20-one and an esterified progestin as the primary metabolites following incubations with labeled progesterone, indicating the presence of a 5α-reductase, 3β-HSD and an acyl transferase. Incubations of scleractinian and alcyonacean homogenates with labeled estrogens or androgens have also indicated the presence of 17β-HSDs (Slattery et al, 1997;Tarrant et al, 2003). Twan et al (2003;2006) have inferred the presence of an aromatase-like enzyme from release of tritiated water following incubations of Euphyllia ancora coral tissue with 1β-3 H-androstenedione.…”

“…Twan et al (2003;2006) have inferred the presence of an aromatase-like enzyme from release of tritiated water following incubations of Euphyllia ancora coral tissue with 1β-3 H-androstenedione. Other studies have failed to detect aromatase activity in cnidarian homogenates following incubations with labeled androgens (Gassman, 1992;Slattery et al, 1997;Tarrant et al, 2003).…”

“…In contrast to the phylogenetically restricted distribution of aromatase activity and CYP19 genes, 17β-HSD activity is commonly detected in incubations with invertebrate tissues including echinoderms Watts et al, 1994), crustaceans (Swevers et al, 1991), molluscs (Matsumoto et al, 1997), and cnidarians (Slattery et al, 1997;Tarrant et al, 2003). 17β-HSDs may be members of either the SDR or the AKR superfamily and catalyze the reversible oxidation or reduction of substrates, including 17-ketosteroids (reviewed by .…”

Hormonal signaling in cnidarians: do we understand the pathways well enough to know whether they are being disrupted?

“…Together these observations prompted speculation that free or conjugated estrogens might serve as chemical cues or pheromones to stimulate coral spawning, but the source of sex steroids in cnidarian tissues has not been demonstrated. Low levels of estrogen synthesis from androgen substrates by coral homogenates has been reported in one study (Twan et al, 2003), but other studies have not detected estrogen synthesis (Slattery et al, 1997;Tarrant et al, 2003). The mechanism of steroid hormone action in cnidarian tissues is also unknown.…”