PMID- 31982399 OWN - NLM STAT- MEDLINE DCOM- 20200804 LR - 20200804 IS - 1095-6840 (Electronic) IS - 0016-6480 (Linking) VI - 290 DP - 2020 May 1 TI - 17beta-Hydroxysteroid dehydrogenase type 12 is responsible for maturation-inducing steroid synthesis during oocyte maturation in Nile tilapia. PG - 113399 LID - S0016-6480(19)30216-3 [pii] LID - 10.1016/j.ygcen.2020.113399 [doi] AB - 17alpha, 20beta-Dihydroxy-4-pregnen-3-one (DHP) is a maturation-inducing steroid in many teleost fish. Carbonyl reductase-like 20beta-hydroxysteroid dehydrogenase (CR/20beta-HSD) is a candidate enzyme responsible for DHP production during oocyte maturation in various fish, including Nile tilapia. However, a novel type of 17beta-hydroxysteroid dehydrogenase, type 12-like (17beta-HSD12L), is responsible for DHP production during oocyte maturation in masu salmon. 17beta-HSD12 (presumably orthologous to salmon 17beta-HSD12L) has been detected in Nile tilapia; however, its enzymatic activity and specific ability to convert the DHP substrate 17alpha-hydroxyprogesterone (17OHP) have not been examined. This study aimed to determine whether CR/20beta-HSD or 17beta-HSD12 is responsible for DHP production during oocyte maturation in the Nile tilapia. Mammalian expression vectors containing tilapia hsd17b12 or CR/20bhsd were transfected into HEK293T cells, followed by incubation with 17OHP. HEK293T cells transfected with hsd17b12 exhibited a strong ability to convert exogenous 17OHP to DHP (73.8% yield). Cells transfected with CR/20bhsd or the control vector converted only 7.4% and 7.5% of 17OHP to DHP, respectively. In addition, based on LC-MS/MS analyses, 17beta-HSD12 did not convert any substrates other than 17OHP, including DHP, adrenosterone, androstenedione, estrone, testosterone, 11-ketotestosterone, and estradiol-17beta. CR/20beta-HSD showed strong 17beta-HSD oxidoreductase activity especially with adrenosterone and androstenedione. Tissue-specific hsd17b12 expression analyzed by RT-PCR showed that hsd17b12 mRNA was strongest amplification in full-grown follicles. Finally, full-grown ovarian follicles were incubated with salmon pituitary extract (SPE, 100 microg/mL) or human chorionic gonadotropin (HCG, 100 IU/mL) to induce 20beta-HSD activity in vitro, and enzyme activity was assessed by co-incubation with 100 ng/mL 17OHP for 2, 4, 8, and 16 h. Conversion of 17OHP to DHP by ovarian follicles incubated with SPE and HCG peaked at 16 h, subsequent with increased follicular hsd17b12 mRNA levels, which were significantly higher than those in control incubations. However, the levels of CR/20bhsd mRNA remained low and did not differ among time points. The present study strongly suggests that 17beta-HSD12, and not CR/20beta-HSD, is the 20beta-HSD responsible for DHP production by ovarian follicles during oocyte maturation in Nile tilapia. CI - Copyright (c) 2020 Elsevier Inc. All rights reserved. FAU - Aranyakanont, Chak AU - Aranyakanont C AD - Graduate School of Fisheries Sciences, Hokkaido University , Minato-cho 3-1-1, Hakodate, Hokkaido 041-8611, Japan. Electronic address: chak@eis.hokudai.ac.jp. FAU - Ijiri, Shigeho AU - Ijiri S AD - Graduate School of Fisheries Sciences, Hokkaido University , Minato-cho 3-1-1, Hakodate, Hokkaido 041-8611, Japan. Electronic address: ijiri@fish.hokudai.ac.jp. FAU - Hasegawa, Yuya AU - Hasegawa Y AD - Graduate School of Fisheries Sciences, Hokkaido University , Minato-cho 3-1-1, Hakodate, Hokkaido 041-8611, Japan. Electronic address: y-hasegawa1031@eis.hokudai.ac.jp. FAU - Adachi, Shinji AU - Adachi S AD - Graduate School of Fisheries Sciences, Hokkaido University , Minato-cho 3-1-1, Hakodate, Hokkaido 041-8611, Japan. Electronic address: s-adachi@fish.hokudai.ac.jp. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20200123 PL - United States TA - Gen Comp Endocrinol JT - General and comparative endocrinology JID - 0370735 RN - EC 1.1.- (17-Hydroxysteroid Dehydrogenases) RN - EC 1.1.1.51 (3 (or 17)-beta-hydroxysteroid dehydrogenase) SB - IM MH - 17-Hydroxysteroid Dehydrogenases/*metabolism MH - Animals MH - Chromatography, Liquid/*methods MH - *Cichlids MH - Female MH - Humans MH - Mass Spectrometry/*methods MH - Oocytes/*metabolism OTO - NOTNLM OT - 17beta-HSD12 OT - Maturation-inducing steroid OT - Nile tilapia OT - Oocyte maturation EDAT- 2020/01/27 06:00 MHDA- 2020/08/05 06:00 CRDT- 2020/01/27 06:00 PHST- 2019/05/09 00:00 [received] PHST- 2020/01/10 00:00 [revised] PHST- 2020/01/20 00:00 [accepted] PHST- 2020/01/27 06:00 [pubmed] PHST- 2020/08/05 06:00 [medline] PHST- 2020/01/27 06:00 [entrez] AID - S0016-6480(19)30216-3 [pii] AID - 10.1016/j.ygcen.2020.113399 [doi] PST - ppublish SO - Gen Comp Endocrinol. 2020 May 1;290:113399. doi: 10.1016/j.ygcen.2020.113399. Epub 2020 Jan 23.