Plasma levels of ovarian steroids, including 17 alpha-20 alpha-dihydroxy-4-pregnen-3-one and 3 beta,17 alpha,20 alpha-trihydroxy-5 beta-pregnane, in female dabs (Limanda limanda)--marine flatfish--induced to mature and ovulate with human chorionic gonadot | - CCMAR -

Journal Article

TitlePlasma levels of ovarian steroids, including 17 alpha-20 alpha-dihydroxy-4-pregnen-3-one and 3 beta,17 alpha,20 alpha-trihydroxy-5 beta-pregnane, in female dabs (Limanda limanda)--marine flatfish--induced to mature and ovulate with human chorionic gonadot
Publication TypeJournal Article
AuthorsCanario, AVM, Scott, AP
Year of Publication1990
JournalGen Comp Endocrinol
Volume77
Issue2
Date Published1990 Feb
Pagination177-91
ISSN0016-6480
KeywordsAnimals, Chorionic Gonadotropin, Female, Flatfishes, Hydroxyprogesterones, Oocytes, Ovulation, Pregnanes, Pregnenes
Abstract

Human chorionic gonadotrophin (HCG) effectively stimulated oocyte final maturation and ovulation in female dabs (Limanda limanda) within 5 days of injection, and this was accompanied by significant changes in blood plasma steroid levels. The steroids which showed the greatest responses to the HCG injections were the ones previously found to be the major products of the ovaries in vitro: 17 alpha-20 alpha-dihydroxy-4-pregnen-3-one (17,20 alpha-P) and 3 beta,17 alpha,20 alpha-trihydroxy-5 beta-pregnane (3 beta,17,20 alpha-P-5 beta). 17,20 alpha-P responded more rapidly with peak levels after 32 hr of injection (115 ng ml-1), but 3 beta,17,20 alpha-P-5 beta reached higher levels ca. 12 hr later (320 ng ml-1). Levels of both steroids were not significantly different from initial values by the time of ovulation. 17 alpha,20 beta-Dihydroxy-4-pregnen-3-one, which is likely to be the oocyte maturation-inducing steroid (MIS) in the dab, showed a significant but very variable rise in levels (between 1 and 10 ng ml-1 in individual fish). 17 alpha-Hydroxy-4-pregnene-3,20-dione levels peaked at 6 ng ml-1 between 30 and 36 hr after HCG injection. Of the other C21 steroids identified in the ovaries of teleosts, 17 alpha,20 beta-21-trihydroxy-4-pregnen-3-one could not be detected, and 17 alpha,21-dihydroxy-4-pregnene-3,20-dione (11-deoxycortisol) showed nonsignificant changes compared to the saline-injected controls. HCG caused a decrease in estradiol-17 beta levels within 24 hr, but levels then rose again to a maximum of 8.2 ng ml-1 at ovulation time, possibly caused by the presence of vitellogenic oocytes in the ovaries. Changes in testosterone levels, however, were not significantly different between HCG- and saline-injected females. The role of HCG-responsive C21 steroids in the dab is discussed.

Sapientia

http://www.ncbi.nlm.nih.gov/pubmed/2307341?dopt=Abstract

Alternate JournalGen. Comp. Endocrinol.
PubMed ID2307341
CCMAR Authors