EFFECT OF SUPPRESSION OF THE SURGE OF FOLLICLE-STIMULATING HORMONE WITH PORCINE FOLLICULAR FLUID ON FOLLICULAR DEVELOPMENT IN THE RAT

1981 ◽  
Vol 88 (1) ◽  
pp. 67-71 ◽  
Author(s):  
ANNE N. HIRSHFIELD ◽  
L. V. DE PAOLO
Keyword(s):  
Follicular Fluid ◽  
Follicle Stimulating Hormone ◽  
Follicular Development ◽  
Oestrous Cycle ◽  
Subsequent Cycle ◽  
Stimulating Hormone

To examine the manner in which the FSH surge of one oestrous cycle recruits follicles for ovulation in the subsequent cycle, porcine follicular fluid (PFF) was used to alter the pattern of endogenous FSH secretion during the periovulatory period. Ovaries of animals killed at oestrus or metoestrus were examined histologically for the presence of large follicles (greater than 400 μm in diameter) after treatment. Large follicles were absent in ovaries of all PFF-treated animals at oestrus, while control rats had an average of 2·7 large follicles per ovary. By metoestrus, however, ovaries of rats treated with PFF contained several large, healthy follicles. Only when PFF treatment was continued throughout the evening of oestrus was the appearance of large follicles prevented at metoestrus. Our results suggest that the prolonged oestrous portion of the FSH surge, rather than the pro-oestrous portion, is responsible for follicular recruitment during the normal oestrous cycle in the rat. They also indicate that compensatory follicular development occurs in response to the FSH rebound which has been shown to follow FSH suppression.

Release of 3H2O from 1β,2β[3H]androstenedione by equine granulosa cells

1983 ◽  
Vol 104 (2) ◽  
pp. 227-232 ◽  
Author(s):  
E. V. YoungLai ◽  
J. F. Jarrell
Keyword(s):  
Luteinizing Hormone ◽  
Granulosa Cells ◽  
Negative Correlation ◽  
Follicular Fluid ◽  
Enzyme System ◽  
Follicle Stimulating Hormone ◽  
Significant Negative Correlation ◽  
Oestrous Cycle ◽  
Bicarbonate Buffer ◽  
Stimulating Hormone

Abstract. Granulosa cells were harvested from mares at various stages of the oestrous cycle and incubated in Krebs-Ringer bicarbonate buffer with 1β,2β[3H]androstenedione as substrate. The release of 3H2O expressed as cpm/h/mg protein varied from 44 000 to 768 000 in follicles from 7 mares. The release of 3H2O was not significantly altered by luteinizing hormone, follicle stimulating hormone or pregnant mare's serum gonadotrophin. There was a significant negative correlation between the release of 3H2O and the concentration of progesterone in the follicular fluid. Based on the assumption that the release of 3H2O represent total aromatization, these data suggest that the equine granulosa cells have a very active aromatizing enzyme system.

FSH AND LH LEVELS IN THE INTACT AND UNILATERALLY OVARIECTOMIZED CYCLING RAT

1972 ◽  
Vol 69 (2) ◽  
pp. 267-280 ◽  
Author(s):  
Richard D. Peppler
Keyword(s):  
Plasma Concentrations ◽  
Follicular Development ◽  
Slight Modification ◽  
Oestrous Cycle ◽  
Successive Cycle ◽  
Unilateral Ovariectomy ◽  
Subsequent Cycle ◽  
Intact Rats

ABSTRACT Intact 5-day cycling rats were killed between 8–10 a. m. on each day of the oestrous cycle; experimental rats were unilaterally ovariectomized (ULO) at 9 a. m. on day 1 (oestrus) and killed between 8 and 10 a. m. on days 2, 3, 4 or 1 of the subsequent cycle. Pituitary and plasma concentrations of FSH and LH were measured in both groups of rats. Pituitary FSH concentration was measured by the Steelman-Pohley method with slight modification; plasma FSH by the Igarashi-McCann assay and pituitary and plasma LH concentration by the OAAD method. In intact rats, pituitary FSH values remained constant for the first three days of the cycle, increased on day 4 and reverted to early cycle values by day 5. Plasma FSH increased between days 2 and 3 and days 5 and 1. Pituitary LH concentration remained the same for days 1 and 2; increased two-fold on days 3 and 4, and increased further by day 5. Plasma LH increased between days 2 and 3; other differences between successive cycle days were not apparent. Following ULO on day 1, pituitary FSH increased steadily, but not significantly, for the remaining cycle. Plasma FSH did not change from day 2 through day 1 of the subsequent cycle. Pituitary LH remained low on day 2, increased sharply by day 3 and decreased (50 %) by day 4. Plasma LH also increased between days 2 and 3. Other differences between successive days following unilateral ovariectomy on day 1 were not apparent. Correlation of gonadotrophin activity with follicular development suggests that the mechanism of compensatory ovulation in the rat may be one of an increase in time of exposure to a constant gonadotrophic level for the duration of the oestrous cycle rather than to increased levels of the gonadotrophin.

Relationships between follicle-stimulating hormone, follicle growth and ovulation rate in sheep

1996 ◽  
Vol 8 (2) ◽  
pp. 279 ◽  
Author(s):  
RC Fry ◽  
MA Driancourt
Keyword(s):  
Follicle Stimulating Hormone ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
Follicle Growth ◽  
Group I ◽  
Group 3 ◽  
Group 2 ◽  
Group 1 ◽  
Stimulating Hormone

The changes in follicle-stimulating hormone (FSH) concentration required to affect follicle growth and ovulation rate within individual ewes were examined. Relationships between peripheral FSH concentrations during the late-luteal and follicular phase and subsequent ovulation rates were investigated in 22 ewes from 4 breeds over 3 successive cycles (Experiment 1). Ewes were grouped as follows: Group 1 (n = 6), ewes exhibiting the same ovulation rate at each oestrous cycle: Group 2 (n = 5), ewes with three different ovulation rates at each oestrous cycle; and Group 3 (n = 11), ewes with the same ovulation rate at two oestrous cycles and a different ovulation rate on one occasion. Data from ewes in Group 1 and 3 provided estimates on the variation in FSH concentrations between cycles which were not large enough to alter ovulation rate (range, 0-67% variation in FSH concentration). In Group-2 ewes, there was no consistent association between increases in ovulation rate and the proportional increases in FSH concentrations. Differences in FSH concentrations were often less than those that did not alter ovulation rate in Group-I ewes. Furthermore, only 3 of 11 Group-3 ewes demonstrated high FSH concentrations associated with high ovulation rate (or low FSH concentrations and low ovulation rate) when compared with the concentrations found at the two cycles in which ovulation rate was similar. Hence, there was little evidence that FSH concentrations during the late-luteal and follicular phase are associated with changes in ovulation rate within individual ewes. In Experiment 2, follicles of similar size obtained from the same ewe (FecBFec+ and Romanov) showed markedly different responses in vitro to graded doses of FSH as measured by aromatase activity. It is concluded that, within a ewe, the large variability between gonadotrophin-dependent follicles in their requirement for FSH prevented the expression of any thresholds of ovarian response to FSH.

scholarly journals STUDIES ON THE SIGNIFICANCE OF THE HIGH LEVELS OF FOLLICLE STIMULATING HORMONE FOR FOLLICULAR DEVELOPMENT IN IMMATURE RATS

1976 ◽  
Vol 16 (3) ◽  
pp. 297-305 ◽  
Author(s):  
J. Th. J. UILENBROEK ◽  
Els ARENDSEN de WOLFF-EXALTO ◽  
R. WELSCHEN ◽  
Lily GRIBLING-HEGGE ◽  
Mechtilda DEBETS ◽  
...  
Keyword(s):  
Follicle Stimulating Hormone ◽  
Follicular Development ◽  
Immature Rats ◽  
Stimulating Hormone
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