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Stage-related production of 21-hydroxylated progestins by the dogfish (Squalus acanthias) testis. 1993

T P Barry, and P Thomas, and G V Callard
Department of Biology, Boston University, MA 02215.

Using shark (Squalus acanthias) testicular microsomes and [3H]progesterone ([3H]P) and [3H]17 alpha-hydroxyprogesterone ([3H]17 alpha-P) as substrates, two major products of 21-hydroxylase action were identified; respectively, 21-hydroxy-4-pregnen-3-one (11-deoxycorticosterone, DOC) and 17 alpha,21-dihydroxy-4-pregnen-3-one (11-deoxycortisol,S). Additional products of 17 alpha-hydroxylase/C-17,20-lyase action were detected: 17 alpha-hydroxyprogesterone (17 alpha P), testosterone (T), and androstenedione (AE). When microsomes derived from tissues in premeiotic (PrM), meiotic (M), and postmeiotic (PoM) stages of spermatogenesis were compared, maturation-related increases were observed with both 21-hydroxylase (3- to 20-fold) and 17 alpha-hydroxylase (2- to 6-fold). With [3H]P as tracer, the half-maximal substrate concentrations (Km = 0.2-1.0 microM) and maximal reaction velocities (Vmax = 9-25 pmol/mg protein/min) were similar for both enzymes when assayed in the same preparation, suggesting they compete for available substrate. Also, the presence of 1- or 10-fold molar excess radioinert DOC reduced conversion of [3H]P to 17 alpha-hydroxylated products. [3H]DOC itself was a substrate of 17 alpha-hydroxylation but not C-17,20-lyase action. Expression of 21-hydroxylase and 17 alpha-hydroxylase activities in cultured spermatocysts (intact germ cell/Sertoli cell units) was confirmed by detection of immunoreactive 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one (20 beta-S),S,17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-P), DOC, P and T in spent media. 20 beta-S and S secretion increased and 17 alpha,20 beta-P decreased progressively with stage of maturation, but DOC was similar in all stages. P secretion was maximal and T lowest in M-stage spermatocysts, but when DOC (0.1 microM) was added to PrM or PoM spermatocysts, T output decreased. Taken together, the data suggest that 21-hydroxylating pathways, via direct and indirect mechanisms, affect accumulation of bioactive steroids (P and T) differentially by stage of spermatogenic development. Whether 21-hydroxylated progestins produced in shark testis have paracrine or endocrine actions in their own right remains to be investigated.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008297 Male Males
D002478 Cells, Cultured Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others. Cultured Cells,Cell, Cultured,Cultured Cell
D003460 Crystallization The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Crystalline Polymorphs,Polymorphism, Crystallization,Crystal Growth,Polymorphic Crystals,Crystal, Polymorphic,Crystalline Polymorph,Crystallization Polymorphism,Crystallization Polymorphisms,Crystals, Polymorphic,Growth, Crystal,Polymorph, Crystalline,Polymorphic Crystal,Polymorphisms, Crystallization,Polymorphs, Crystalline
D003900 Desoxycorticosterone A steroid metabolite that is the 11-deoxy derivative of CORTICOSTERONE and the 21-hydroxy derivative of PROGESTERONE 21-Hydroxyprogesterone,Cortexone,Deoxycorticosterone,Desoxycortone,11-Decorticosterone,21-Hydroxy-4-pregnene-3,20-dione,11 Decorticosterone,21 Hydroxy 4 pregnene 3,20 dione,21 Hydroxyprogesterone
D004284 Dogfish Sharks of the family Squalidae, also called dogfish sharks. They comprise at least eight genera and 44 species. Their LIVER is valued for its oil and its flesh is often made into fertilizer. Squalidae,Dogfishes
D006908 Hydroxyprogesterones Metabolites or derivatives of PROGESTERONE with hydroxyl group substitution at various sites.
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013091 Spermatogenesis The process of germ cell development in the male from the primordial germ cells, through SPERMATOGONIA; SPERMATOCYTES; SPERMATIDS; to the mature haploid SPERMATOZOA. Spermatocytogenesis,Spermiogenesis
D013255 Steroid 21-Hydroxylase An adrenal microsomal cytochrome P450 enzyme that catalyzes the 21-hydroxylation of steroids in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP21 gene, converts progesterones to precursors of adrenal steroid hormones (CORTICOSTERONE; HYDROCORTISONE). Defects in CYP21 cause congenital adrenal hyperplasia (ADRENAL HYPERPLASIA, CONGENITAL). Cytochrome P-450 CYP21,Steroid 21-Monooxygenase,21-Hydroxylase,Cytochrome P-450 21-Hydroxylase,Cytochrome P-450 c21,Cytochrome P-450(c-21),Cytochrome P450c21,Progesterone 21-Hydroxylase,Steroid-21-Hydroxylase,21 Hydroxylase,Cytochrome P 450 21 Hydroxylase,Cytochrome P 450 CYP21,Cytochrome P 450 c21,P-450 c21, Cytochrome,Progesterone 21 Hydroxylase,Steroid 21 Hydroxylase,Steroid 21 Monooxygenase

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