Free androgens and progestins and their conjugated forms in serum and urine of stellate sturgeon (Acipenser stellatus Pallas) males by Liubov Bayunova (1), adelino Canario (2), T atiana Semenkova (1), elsa CouTo (2), arnold GeraSimov (1) & irina Barannikova (3) AbstrAct. - Stellate sturgeon (Acipenser stellatus Pallas) males from volga river treated with LH-rH-a showed an increase of free, sulfated and glucuronided sex steroid levels in serum and urine at spermiation. Conjugated forms of sex steroids could act as pheromones in sturgeon. key words. - Stellate sturgeon male - Steroids - Sulfates - Glucuronides. Cybium 2008, 32(2) suppl.: 273-274. (1) Central Laboratory of Fish reproduction, 24, Prof. Popova Str., 197022, St. Petersburg, russia. [epl@it4257.spb.edu] (2) Centro de Ciencias do mar, universidade do algarve, 8005-139 Faro, Portugal. (3) Physiological institute St. Petersburg university, 7/9, universitetskaya embankment, 199034, St. Petersburg, russia. Introduction Free steroid levels in the blood serum of stellate sturgeon breeders after hormonal treatment were previously investi- gated (Semenkova et al., 2002; Bayunova et al., 2006). The role of the conjugated forms of sex steroids in sturgeon is still not clear. The aim of this study was to examine the pro- iles of free, sulfated and glucuronided sex steroid levels in the serum and urine in males. Methods Stellate sturgeon males (n = 6) were captured at volga river, delivered to the sturgeon hatchery and held in the ponds 1-2 weeks before experiment. Fish were treated by LH-rH-a to induce spermiation. Blood samples were taken at the time of treatment (0 h) and after 4 h (the beginning of spermiation), 8 and 12 h (at spermiation) and 160 h (after spermiation). urine samples were taken at 0, 4, 8 and 12 h after the treatment. Concentrations (ng/ml) of free, sulfated and glucuronid- ed testosterone (T), 11-ketotestosterone (kT), 17,20-b-dihy- droxy-4-pregnen-3-one (DHP), 17,20-b-21-trihydroxy-4- pregnen-3-one (20bS) and 11-desoxycortisol (S) were meas- ured by radioimmunoassay. results and discussion Free T serum levels, as well as its sulfate and glucuro- nided S levels, increased 8 h after the treatment. Sulfated kT and glucuronided DHP levels tended to increase at spermia- tion. Free 20bS and S and glucuronided S levels increased at the end of experiment and glucuronided DHP levels signii- cantly decreased at this moment (Tab. i). Free 20bS urine levels rose 12 h, free and sulfated DHP levels elevated 8 h after the treatment (Tab. ii). conclusions Free and conjugated sex steroid levels were elevated in serum and urine at spermiation. it is suggested that these changes may be related to a possible role of these steroids in pheromonal communication in sturgeon. Acknowledgements. - The study was supported by a Collaborative Linkage Grant ref. no: LST.CLG.979493 of the naTo SCienCe ProGramme, Cooperative Science and Technology Sub-Pro- gramme. Form Steroid Time after the treatment (h) 0 4 8 12 160 Free T 46.9 ± 12.28 50.6 ± 12.06 96.8 ± 34.87* 141.6 ± 54.37 156.7 ± 27.84 kT 54.4 ± 17.81 53.8 ± 14.36 33.6 ± 8.78 39.2 ± 15.61 45.4 ± 14.97 20bS 0.9 ± 0.19 1.2 ± 0.23 1.0 ± 0.13 1.3 ± 0.26 1.5 ± 0.18** DHP 0.3 ± 0.09 0.4 ± 0.14 0.3 ± 0.03 0.3 ± 0.04 0.3 ± 0.05 S 1.1 ± 0.24 1.1 ± 0.11 1.3 ± 0.32 1.9 ± 0.52 2.3 ± 0.56* Sulfate T 4.0 ± 0.30 4.3 ± 0.22 6.2 ± 0.66* 6.3 ± 1.41 6.2 ± 0.87 kT 0.7 ± 0.17 0.5 ± 0.09 1.2 ± 0.25 0.7 ± 0.14 1.0 ± 0.47 20bS 0.4 ± 0.18 0.8 ± 0.40 0.4 ± 0.13 0.3 ± 0.03 0.2 ± 0.07 DHP 0.1 ± 0.02 0.3 ± 0.17 1.0 ± 0.87 1.1 ± 0.59 0.1 ± 0.05 S 2.2 - 0.5 ± 0.06 1.0 ± 0.57 1.2 Glucuronide T 1.0 ± 0.06 0.4 ± 0.06 0.6 ± 0.17 0.7 ± 0.34 0.6 ± 0.19 kT 4.3 ± 1.10 2.1 ± 0.70 2.3 ± 1.12 2.4 ± 1.03 3.0 ± 1.10 20bS 0.5 ± 0.12 0.6 ± 0.09 0.8 ± 0.29 0.5 ± 0.09 0.6 ± 0.21 DHP 0.7 ± 0.29 0.9 ± 0.18 1.4 ± 0.42 0.8 ± 0.25 0.5 ± 0.11 x S 0.3 ± 0.01 0.4 ± 0.07 0.6 ± 0.15* 0.6 ± 0.16 1.1 ± 0.27* Table i. - Free and conjugated sex ster- oid levels (ng/ml) in the serum after LH-rH-a treatment. The differences are signiicant: *: p < 0.05; ** : p < 0.01 - in comparison with point “0”; x : p < 0.05 - in comparison with point “8” (using T-Student paired test)