title: Conjugates of ovarian steroids, including 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (maturation-inducing steroid), accumulate in the urine of a marine teleost (plaice; Pleuronectes platessa).
abstract: Free and conjugated 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P), 17 alpha,21-dihydroxy-4-pregnene-3,20-dione (11-deoxycortisol) and 3 alpha,17 alpha,21-trihydroxy-5 beta-pregnan-20-one (3 alpha,17,21-P-5 beta) were measured by radioimmunoassay in matching blood plasma and urine samples from plaice (Pleuronectes platessa) females at several ovarian maturity stages: post-vitellogenesis (IV), final oocyte maturation (V), and ovulation (VI). Free steroids were generally low in all samples. Conjugated steroids were up to 2 orders of magnitude higher in urine than in plasma samples. Conjugated 17,20 beta-P was higher in stage V than in stage IV or VI females. Conjugated 11-deoxycortisol was higher in stage IV and V females. Conjugated 3 alpha,17,21-P-5 beta was higher in stage V and VI females. These results support earlier studies which indicated that 17,20 beta-P was the most likely maturation-inducing steroid (MIS) in plaice, and that the urine might be a vehicle for steroid pheromones synthesized by the gonads.
authors: Universidade do Algarve, Faro, Portugal.
authors: A V
authors: AV
authors: Canario
authors: A P
authors: AP
authors: Scott
mesh_terms: D000818:Animals; D003350:Cortodoxone / Q000031:analogs & derivatives / Q000652:urine; D005260:Female; D005412:Flatfishes / Q000378:metabolism*; D006908:Hydroxyprogesterones / Q000652:urine*; D009866:Oogenesis; D010060:Ovulation; D011863:Radioimmunoassay; D013997:Time Factors
chemical_list: D006908:Hydroxyprogesterones; C021012:17 alpha,20 beta-dihydroxypregn-4-en-3-one; C009412:tetrahydro-11-deoxycortisol; D003350:Cortodoxone