RE-EXAMINATION OF THE PRESENCE OF CORTICOSTEROIDS IN TWO CYCLOSTOMES, THE ATLANTIC HAGFISH ( MYXINE GLUTINOSA L.) AND THE SEA LAMPREY ( PETROMYZON MARINUS L.)

SUMMARY Fluorescence analyses and observations of plasma extracts on thin-layer chromatoplates including sulphuric acid chromogens failed to indicate the high concentrations of cortisol and corticosterone in Atlantic hagfish and sea lamprey reported by other workers. Double isotope derivative assays of Atlantic hagfish plasma and sea lamprey plasma failed to provide rigorous proof of the presence of these steroids. Presumptive adrenocortical tissue from Atlantic hagfish and sea lamprey, incubated with radioactive steroids as precursors, failed to give any transformation to cortisol or corticosterone. However, sea lamprey incubations did produce 17α-hydroxyprogesterone from progesterone. No evidence was found for the presence of 17α-hydroxyprogesterone in microgram quantities in the plasma. These findings are discussed in relation to previous studies in which high concentrations of cortisol and corticosterone were reported.