GROWTH AND DIFFERENTIATION OF LARGE ANTRAL FOLLICLES AFTER SPONTANEOUS LUTEOLYSIS IN HEIFERS: CHANGES IN CONCENTRATION OF HORMONES IN FOLLICULAR FLUID AND SPECIFIC BINDING OF GONADOTROPINS TO FOLLICLES l
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چکیده
The objective of the present study was to characterize changes in growth, concentrations of steroids in follicular fluid (FF) and gonadot ropin receptors of individual antral follicles after spontaneous luteolysis in heifers and to reexamine our hormonal method of classifying healthy and atretic follicles. Groups of heifers were ovariectomized (OVX) before regression of corpora lutea on d 17, 18 and 19 of an estrous cycle and after regression of corpora lutea at t ime periods before, during and after preovulatory gonadotropin surges. Each follicle 96 mm in diameter was examined for concentrat ion of progesterone, androstenedione, testosterone and estradiol-17fl in FF and capacities of granulosal and thecal cells to specifically bind ~2SI-bovine follicle stimulating hormone (bFSH) or 12Si.human chorionic gonadotropin
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