ENDOCRINE CONTROL IN MATURE OF OF AVIAN OOCYTER

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1 Effects of chicken gonadotrophins, estradiol and norepinephrine (NE) on basal and LH-stimulated progesterone production in granulosa cells isolated from the largest preovulatory follicle of the ovary of the hen was examined in a monolayer culture using a defined serumfree medium. After 4 days of the culture, when the granulosa cells were exposed to LH, FAH, estradiol or NE for 4 hr. the production of progesterone was stimulated by LH in a dose dependent manner, but only slightly by FSH. and not by estradiol and NE. When the cells were exposed to FSH, estradiol or NE together with LH for 4 hr. FSH promoted the LH-stimulated progesterone production in a dose-dependent manner. but not estradiol and NE. When the cells were primed with FSH. estradiol or NE for various hours prior to the LH-stimulated progesterone production on 4 days of the culture. the priming with those hormones for more that at least 36 hr enhanced the LH-stimulated progesterone production in dose-dependent manner with … More out an increase in the number of cells.These results suggest that in avian granulosa cells of larger follicles, neither FSH, estrogen or NE alone stimulate the production of progesterone but these hormones prime the cells to increase the responsiveness to LH for progesterone production, and FSH also augments the LH-stimulated progesterone production.2 The activity of plasminogen activator of granulosa cells of the largest and the second largest preovulatory folicle (Fl and F2. respectively) in the ovary of the hen at various times during a period between ovulations of the initial and the second (C2) ovum of a clutch was measured by the method of Knecht (1986) using a chicken plasminogen preparation which had been extracted from the rooster serum and purified by lysine-sepharose 4B affinity chromato graphy and a Sephadex G-25 gel filtration. The activity of both Fl and F2 changed similarly and showed a higher levels 12 h before C2 ovulation and not near the time of the ovulation.The results suggest that the plasminogen activator in the granulosa cells of the ovary of the hen may be involved in a mechanism other than the follicular rupture for ovualtion.3 Inhibin activity was investigated using chicken granulosa cells culture medium. Chicken granulosa cells were collected individually from the largest (FI) and the third largest follicle (F3) of the ovary, dispersed using enzyme and incubated in a suspension method or cultured in a monolayer method in vitro. Cultured medium was assessed for follicle-stimulating hormone (FSH) inhibiting (inhibin) activity using the rat pituitary cell culture method.The FSH secretion from cultured rat pituitary cells was suppressed by experimental increasing of the amounts of granulosa cell culture in a dose-dependent manner, though luteinizing hormone (LH) secretion was not affected in a dose-dependent manner. Inhibin activity of the granulosa cell culture medium derived from Fl follicles was higher than that from F3 follicles. Less