Steroid hormones concentration of the preovulatory ovarian follicles of the goose P. Paściak1, D. Wojtysiak2 1JSR Polska Ltd.,42-510 Wojkowice Kościelne 28, Poland Email [email protected]2Department of Animal Anatomy, University of Agriculture, 30-059 Kraków, PolandIntroduction Ovarian follicles are the most important steroids producing structures of the avian ovary. The ovary of a mature goose generally contains 7-9 large preovulatory follicles arranged in a follicular hierarchy, several postovulatory follicles, and numerous small follicles, which have not entered the follicular hierarchy. It has been reported that in avian preovulatory follicles biosynthesis of sex steroid changes during maturation (Gomez et al., 1998; Lee et al., 1998). The cell theory for steroid production suggested that granular layer of preovulatory follicles primarily produce progesterone that are required as substrate for the production of androgen and estradiol by theca layer (Huang et al., 1979). The recently multiple-cell theory of steroidogenic suggest that theca layer can also synthesize progesterone, androgen and estradiol independent of granulosa layer (Nitta et al., 1991). Despite strong interest in bird reproductive system there is little information on the goose ovarian system. Therefore the aim of the study was to determine concentration of progesterone, estradiol and androgens in different sizes of the preovulatory follicles. Materials and Methods The concentrations of steroid hormones (P4 – progesterone, E2 – estradiol and A – androgens) were determined in isolated theca and granular layer of the three largest preovulatory ovarian follicles of the goose. The studies were carried out on 12 one-year-old Zatorska geese during the reproductive cycle. Preovulatory follicles (F1, F2 and F3) which had entered the hierarchy were isolated from ovaries approximately after egg was layed and before the ovulation. Yolk was removed from the tissues and were homogenized. Steroid hormones were measured by RIA methods (Spectria Orion Diagnostic, Finland). The concentrations of steroid were computed in pg or ng/mg protein and were expressed as means ± SD. Statistical differences were calculated using Student’s t-test and Duncan’s new test. Results Mean steroid concentration data for the study are given in Table 1. The major findings of the present study were, that in preovulatory follicles of the goose; 1.) maximum level P4 was recorded in granular layer and the
concentration P4 significant increased as follicles matured. In all examined follicles level P4 in the theca layer was
significantly lower than the granular layer; 2.) the greatest E2 concentration was observed in the theca layer, and next
level E2 was decreased significant with follicular size. In the granular layer the E2 concentration was very low and
remained constant during the third and second position in the hierarchy, and declined throughout the first position; 3.)changes in concentrations in the theca and granular layer were similar. There was a gradual decrease in both layersduring follicular maturation. Table 1 Steroid concentration P4 (ng/mg protein ± SD), E2 and A (pg/mg protein ± SD) in the three largest preovulatory
follicles (F1, F2, F3) of the goose. Progesterone [ng] Estradiol [pg] Androgens [pg]
a, b, c, d, e f - significant p<0,05bs – below sensitivity
Conclusions It was concluded that, similar to hen, granular layer of the preovulatory follicles of the goose is the major source of progesterone while theca layer is the principle source of estradiol. Additionally, in the granular layer steroidogenic activity dramatic increase while in the theca layer gradual decrease as the follicle approaches ovulation. References Gomez Y., Velazquez P. N., Juarez-Oropeza M. A., Pedernera E. 1998. Steroid metabolism in granulosa and theca interna cells from preovulatory follicles of the domestic fowl (Gallus domesticus). Anim. Reprod. Sci.,52: 81-91. Huang E. S.-R., Kao K. J., Nalbandov A. V. 1979. Synthesis of sex steroids by cellular components of chicken follicles. Biol. Reprod., 20, 454-461. Lee K. A., Volentine K. K., Bahr J. M. 1998. Two steroidogenic pathways present in the chicken ovary: theca layer prefers ∆5 pathway and granulosa layer prefers ∆4 pathway. Domest. Anim. Endocrinol., 15:1-8. Nitta H., Osawa Y., Bahr J.M. 1991. Multiple steroidogenic cell populations in the theca of preovulatory follicles of the chicken ovary. Endocrinology, 129: 2033-2040.
21st century basics: finance Dan Watkiss , contributing editor this merger with the New Deal-era statute. MidAmerican nor its majority-owner Moreover, Congress could intervene: Both Berkshire Hathaway lays claim to syner-hen last I penned this column, houses of the 109th Congress continue gistic business drivers. Nor do they foresee I addressed “back to basics,” or to play thei
Skin and Soft Tissue Infections Cellulitis Note : The most common etiology of cellulitis with purulent drainage is S. aureus , although Group A streptococci and other streptococcal species can also present in this manner. TREATMENT The following regimens include coverage for MSSA, community-acquired MRSA (CA- MRSA), and streptococci . Coverage for gram negative organisms is not need