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Circulating steroid hormones of anadromous sea lampreys under various experimental conditions

1982; Elsevier BV; Volume: 48; Issue: 2 Linguagem: Inglês

10.1016/0016-6480(82)90025-9

1095-6840

Yair Katz, Larry Dashow, August Epple,

Cephalopods and Marine Biology

Presence, sex differences, and stress response of 6 circulating steroids were studied with specific radioimmunoassays in anadromous Petromyzon marinus. There were no detectable plasma levels of 5α-dihydrotestosterone. Testosterone was absent in 75 of 77 blood samples, and progesterone was present in 33 of 77 blood samples from 27 lampreys of both sexes. No statistically significant sex differences in the plasma levels of androstenedione, estrone, and estradiol were found. The plasma levels of these steroids were studied under the following experimental conditions: (1) chronic surgical stress (heart cannulation); (2) acute short-term stress (agitation); (3) decapitation without anesthesia within 1 min following capture; (4) decapitation after 10 min of submersion in a 0.05% solution of the anesthetic tricaine methanesulfonate. The androstenedione titers increased in response to all four experimental conditions, while estrone showed no statistically significant changes. Progesterone increased only during chronic stress. The estradiol levels dropped after heart cannulation and also 24 hr after agitation. The appearance of testosterone in 2 animals during chronic stress cannot be explained. Our data suggest that in adult lampreys (1) the roles of "sex" steroids differ from those typical for many gnathostomes; (2) androstenedione is a stress-related substance; (3) circulating androstenedione and estradiol may be—mainly or exclusively—released from different sources.