Seasonal response of carp (Cyprinus carpio) ovarian cells to stimulation by various hormones as measured by steroid secretion: tissue culture approach.
OBJECTIVE
To study seasonal variation of steroid secretion by dispersed carp ovarian follicular cells as influenced by carp pituitary homogenate (CPH), human chorionic gonadotropin (hCG) or 17alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 betaOH-P).


METHODS
Carp ovaries were collected each month throughout the year from January to December. The cells of ovarian follicles were dispersed by trypsin treatment and cultivated as monolayers. Control cultures were grown in medium M199 alone. Media for experimental cultures were supplemented either with CPH, hCG or (17alpha,20 betaOH-P). The direct effect of these three factors on progesterone (P4), androgens and estradiol (E2) secretion by isolated follicular cells in cell culture was assayed by appropriate RIA.


RESULTS
In control cultures the highest levels of P4, A and E2 appeared before spawning time and at the time of vitellogenesis. Under the influence of CPH the secretion of P4 increased in December. Significant increase of androgen secretion was seen in May, while that of E2 appeared in February, May, September and December. In December, February and November the secretion of E2 was suppressed by hCG. The most intense stimulation of steroidogenesis was observed after 17alpha,20 betaOH-P treatment. It increased the level of P4 at the time of its maximum in the control cultures; androgen level was elevated throughout the whole year; E2 secretion was stimulated only during the spawning time, while during vitellogenesis E2 level declined.


CONCLUSIONS
It was shown that steroid secretory pattern of follicular cells changed during the year and that the three factors used (pituitary homogenate, hCG and 17alpha,20 betaOH-P) exerted direct influence upon steroids secretion.
Galas
J
J
Laboratory of Animal Endocrinology and Tissue Culture, Institute of Zoology, Jagiellonian University, 30-060 Krakow, Poland. galas@zuk.iz.uj.edu.pl
Epler
P
P
Stoklosowa
S
S
D000728:Androgens / Q000378:metabolism; D000818:Animals; D002347:Carps / Q000502:physiology*; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D046508:Culture Techniques; D004958:Estradiol / Q000378:metabolism; D005260:Female; D006908:Hydroxyprogesterones / Q000494:pharmacology; D010053:Ovary / Q000187:drug effects / Q000378:metabolism*; D010902:Pituitary Gland / Q000502:physiology; D011374:Progesterone / Q000378:metabolism; D012098:Reproduction; D012621:Seasons; D013256:Steroids / Q000378:metabolism*; D014818:Vitellogenesis
D000728:Androgens; D006063:Chorionic Gonadotropin; D006908:Hydroxyprogesterones; D013256:Steroids; C007433:17,20-dihydroxy-4-pregnen-3-one; D011374:Progesterone; D004958:Estradiol