scholarly journals VARIATIONS IN PLASMA LH LEVELS DURING THE OVULATORY CYCLE OF THE HEN, GALLUS DOMESTICUS

Reproduction ◽  
1973 ◽  
Vol 35 (3) ◽  
pp. 561-564 ◽  
Author(s):  
S. C. WILSON ◽  
P. J. SHARP
Keyword(s):  
Gallus Domesticus ◽  
Ovulatory Cycle

Changes in 3β-hydroxy-Δ5-steroid dehydrogenase activity in granulosa tissue during the ovulatory cycle of the laying hen (Gallus domesticus)

1985 ◽  
Vol 106 (3) ◽  
pp. 269-273 ◽  
Author(s):  
D. G. Armstrong
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Domestic Fowl ◽  
Ovarian Follicle ◽  
Laying Hen ◽  
Gallus Domesticus ◽  
Ovulatory Cycle ◽  
Lh Surge ◽  
Maximal Plasma ◽  
Steroid Dehydrogenase

ABSTRACT The object of this study was to examine changes in the activity of granulosa 3β-hydroxy-Δ5-steroid dehydrogenase during the ovulatory cycle of the domestic fowl. The enzyme activity in granulosa tissue from the largest follicle increased significantly during the period 8–14 h before an expected ovulation. The increase in activity occurs before the preovulatory surge of LH and near the time of lights off. During the 4–8 h period before an ovulation, i.e. the time of maximal plasma LH concentrations, 3β-hydroxy-Δ5-steroid dehydrogenase activity decreased in granulosa tissue from the largest follicle. This observation is explained by proposing that the enzyme is inhibited by the large amounts of progesterone found in the tissue at this time. The results indicate that important biochemical changes are taking place within granulosa tissue of the largest ovarian follicle before the preovulatory LH surge. J. Endocr. (1985) 106, 269–273

CONVERSION OF [4-14C]PROGESTERONE TO ANDROSTENEDIONE IN VITRO BY THECAL TISSUE FROM THE OVARY OF THE DOMESTIC FOWL (GALLUS DOMESTICUS)

1981 ◽  
Vol 89 (2) ◽  
pp. 283-288 ◽  
Author(s):  
CHARLOTTE A. LLEWELYN
Keyword(s):  
Domestic Fowl ◽  
Gallus Domesticus ◽  
Ovulatory Cycle ◽  
Tissue Homogenates

The conversion of [4-14C]progesterone to androstenedione by thecal tissue homogenates from the large yellow follicles of the hen ovary was measured at two periods of the ovulatory cycle after incubation for 1 h in the presence of cofactors. Production of androstenedione by the largest follicle, F1, was reduced significantly 1–2 h before ovulation compared with 15 h before ovulation, whereas production of an unidentified androgen increased. These differences were not observed in the next largest follicles, F2 and F3. Thecal tissue homogenates from all the follicles converted [4-14C]progesterone to 17 α-hydroxyprogesterone, androstenedione and testosterone.

CONTROL OF THE PREOVULATORY SURGE OF LUTEINIZING HORMONE IN THE HEN (GALLUS DOMESTICUS): THE ROLE OF PROGESTERONE AND ANDROGENS

1978 ◽  
Vol 77 (1) ◽  
pp. 57-65 ◽  
Author(s):  
J. B. WILLIAMS ◽  
P. J. SHARP
Keyword(s):  
Luteinizing Hormone ◽  
Dark Period ◽  
Ovarian Follicle ◽  
Gallus Domesticus ◽  
Ovulatory Cycle ◽  
Blood Samples ◽  
Lh Surge ◽  
Before And After ◽  
Small Rise

Peripheral blood samples were taken from laying hens at frequent intervals during various periods of the ovulatory cycle in order to detect small changes in the concentrations of progesterone and androgen which might be important in initiating the preovulatory release of LH. Blood samples were taken from seven hens at 1 h intervals for 3 h when the ovary contained a mature (C1) follicle and on another occasion, when the largest ovarian follicle was immature. The concentrations of progesterone and androgens in the plasma were 30% higher when there was a mature C1 follicle present in the ovary than when there was not, but this increase was significant (P < 0·05) only for progesterone. The concentrations of progesterone and androgens were also measured in blood samples taken at 30 min intervals during the 3 h before and after the initiation of the first preovulatory LH surge of a sequence. The hens were kept on a lighting schedule of 14 h light/day and the first LH surge of a sequence was initiated at the beginning of the dark period. Just after the onset of darkness there was a small increase in the concentration of LH in the plasma and a subsequent, larger preovulatory release of LH. The first increase in the level of LH was associated with a small rise in the concentrations of androgens and progesterone in the plasma while the preovulatory release of LH was accompanied by a much larger increase in the secretion of these steroids. It is proposed that the increase in the level of LH in the plasma at the onset of darkness stimulates the maturing ovarian follicles to secrete progesterone and androgens and that the quantities of these steroids secreted (particularly of progesterone) depends on the maturity of the largest ovarian follicle. If the largest ovarian follicle is mature, then the increase in the level of LH in the plasma associated with the onset of darkness stimulates the secretion of a quantity of progesterone sufficient to cause the preovulatory surge of LH. A diurnal increase in the concentration of LH in the plasma could, therefore, be responsible for timing the preovulatory surges of LH so that they are only initiated at night.

Progesterone, androstenedione and oestradiol content of theca and granulosa tissues of the four largest ovarian follicles during the ovulatory cycle of the hen (Gallus domesticus)

1984 ◽  
Vol 103 (1) ◽  
pp. 71-76 ◽  
Author(s):  
R. J. Etches ◽  
C. E. Duke
Keyword(s):  
Ovarian Follicles ◽  
Gallus Domesticus ◽  
Ovulatory Cycle ◽  
The Third ◽  
Progesterone Production

ABSTRACT The progesterone, androstenedione and oestradiol contents of the theca and granulosa tissues of the four largest follicles in the ovarian hierarchy of the hen were determined. The granulosa tissue contained significantly (P < 0·05) more progesterone and less androstenedione and oestradiol than the theca tissue. The content of progesterone was greatest in the granulosa tissue of the first three follicles in the hierarchy and in each of these follicles there was a peak in progesterone content of the granulosa 4 h before ovulation. The theca of the second, third and fourth follicles and the granulosa of the third and fourth follicles contained significantly (P < 0·05) more androstenedione than either tissue in the largest follicle. The content of androstenedione was maximal approximately 8 h before ovulation in both tissues of the second and third follicles. The content of oestradiol in the granulosa did not vary as follicles changed position within the hierarchy or during the ovulatory cycle. The oestradiol content of the theca tissue remained constant during the third and fourth positions in the hierarchy and declined throughout the second and first positions until a nadir was observed approximately 20 h before ovulation. It was concluded that the synthesis of androstenedione and oestradiol ceases in both follicular tissues after the follicle is exposed to the penultimate preovulatory surge of LH and that progesterone production is stimulated in the granulosa of the three largest follicles at the time of the preovulatory release of LH. J. Endocr. (1984) 103, 71–76

CHANGES IN PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE AFTER INJECTION OF PROGESTERONE AT VARIOUS TIMES DURING THE OVULATORY CYCLE OF THE DOMESTIC HEN (GALLUS DOMESTICUS)

1975 ◽  
Vol 67 (1) ◽  
pp. 59-70 ◽  
Author(s):  
SUSAN C. WILSON ◽  
P. J. SHARP
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Concentrations ◽  
Gallus Domesticus ◽  
Ovulatory Cycle ◽  
Lh Surge ◽  
Incremental Change ◽  
The Mean ◽  
Domestic Hen

SUMMARY Changes in plasma LH concentrations after i.m. injections of 0·5 mg progesterone/kg at various stages of the ovulatory cycle were measured by radioimmunoassay. Four types of response were observed. (1) When the steroid was injected between 4 h after and 12 h before an ovulation, LH levels started to rise after 15–45 min and reached peak values within 90–120 min. The mean maximal incremental change in the level of LH was 1·58 ± 0·10 (s.e.m.) ng/ml (n = 37). (2) In contrast, when progesterone was injected 12–8 h before ovulation, i.e. immediately before a spontaneous pre-ovulatory LH surge, the resulting mean maximal incremental change in LH level, 0·79 ± 0·12 ng/ml (n = 9), was significantly smaller (P < 0·001). (3) If progesterone was injected 8–4 h before ovulation, i.e. when pre-ovulatory LH levels were rising, they immediately started to rise more rapidly and reached peak values within 45 min. The maximal incremental change in the level of LH under these circumstances, 2·34 ± 0·20 ng/ml (n = 12), was significantly greater (P < 0·001 in both cases) than the changes observed in the responses 1 and 2 described above. (4) Levels of LH generally showed no incremental change in response to injections of progesterone given 4–0 h before ovulation, i.e. when pre-ovulatory LH levels were falling. It was concluded that the type of change in plasma LH levels induced by progesterone depended upon the stage of the ovulatory cycle at which the steroid was injected.

Circulating concentrations of inhibin-related proteins during the ovulatory cycle of the domestic fowl (Gallus domesticus) and after induced cessation of egg laying

Reproduction ◽  
2000 ◽  
Vol 119 (2) ◽  
pp. 323-328 ◽  
Author(s):  
T. Lovell ◽  
D Vanmontfort ◽  
V Bruggeman ◽  
E Decuypere ◽  
N. Groome ◽  
...  
Keyword(s):  
Domestic Fowl ◽  
Egg Laying ◽  
Gallus Domesticus ◽  
Ovulatory Cycle ◽  
Related Proteins

LUTEINIZING HORMONE AND PROGESTERONE IN PERIPHERAL BLOOD DURING THE OVULATORY CYCLE OF THE HEN GALLUS DOMESTICUS

1973 ◽  
Vol 57 (1) ◽  
pp. 159-169 ◽  
Author(s):  
B. J. A. FURR ◽  
ROSEMARY C. BONNEY ◽  
ROWENA J. ENGLAND ◽  
F. J. CUNNINGHAM
Keyword(s):  
Luteinizing Hormone ◽  
Peripheral Blood ◽  
Plasma Levels ◽  
Experimental Period ◽  
Gallus Domesticus ◽  
Consistent Pattern ◽  
Ovulatory Cycle ◽  
Neuroendocrine Control

SUMMARY Radioimmunoassays were used to estimate luteinizing hormone (LH) and progesterone in samples of blood taken from individual hens at frequent intervals throughout their respective ovulatory cycles. A consistent pattern in the plasma levels of both hormones was observed. Significantly more LH and progesterone was present in plasma 4–7 h before ovulation than at other times during the cycle. An increase in the level of progesterone either preceded that of LH or the two hormones increased simultaneously. At no time did an increase in the level of LH occur before the rise in progesterone. In those birds which did not ovulate during the experimental period the levels of both hormones remained low. The significance of these findings in relation to the neuroendocrine control of ovulation in the hen is discussed.

Sign in / Sign up

Export Citation Format

Share Document