Corticosteroid activity, in vitro, in interrenal tissue of Atlantic salmon (Salmo salar) parr. 1. Synthetic profiles.

Fresh interrenal tissue of Atlantic salmon (Salmo salar) parr transformed [3H]pregnenolone and [14C]progesterone, in vitro, to double-labeled cortisol and corticosterone with yields of less than 3% 3H and 5% 14C at 0-5 degrees, 8-10 degrees, and 22-24 degrees over various incubation periods. Incubations at 22-24 degrees gave the highest yields. A time-yield study at 22-24 degrees for 0.5 to 3 hr in late March showed that metabolic patterns did not change with time as metabolic yields increased. Double-labeled metabolites, 11-deoxycortisol, 21-deoxycortisol, and 17 alpha-hydroxyprogesterone, were all detected in hatchery-reared Annapolis River stock in April, but not in November. The 3H:14C ratio of cortisol was significantly lower (P < 0.05) in late April than in early November. Isotopic ratios of corticosterone, but not cortisol, differed significantly (P < 0.05) between immature and precocious parr in November. The isolation of double-labeled corticosterone from all incubations, except immature parr in November, may indicate a metabolic role for the 17-deoxycorticosteroids. No differences in the histology of interrenal tissues were found between Spring (April-May) and Autumn (October-November) parr. Sulfuric acid chromogens on TLC typical of cortisol, corticosterone, and 11-deoxycortisol and other, less polar delta-5-steroids, but not cortisone, in amounts estimated to be > or = 0.1 microgram, were detected in head kidney tissues (0.5-4.5 g) and blood plasma (7-18 ml) of parr in July, late November, and early December.