EFFECTS OF ANDROGENS, OESTROGENS AND DEOXYCORTICOSTERONE ACETATE ON PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE IN LAYING HENS

1976 ◽  
Vol 69 (1) ◽  
pp. 93-102 ◽  
Author(s):  
SUSAN C. WILSON ◽  
P. J. SHARP
Keyword(s):  
Luteinizing Hormone ◽  
Laying Hens ◽  
Ovarian Follicle ◽  
Plasma Concentrations ◽  
Contrast Injection ◽  
Ovulatory Cycle ◽  
Maximal Increase ◽  
Deoxycorticosterone Acetate ◽  
Dose Levels ◽  
Lh Secretion

SUMMARY Testosterone, androstenedione, oestrone, oestradiol-17β or deoxycorticosterone acetate (DOCA) were injected intramuscularly at several dose-levels and at various stages of the ovulatory cycle, and subsequent changes in plasma LH concentration were measured by radioimmunoassay. In 19 out of 24 hens, injection of 0·1, 0·5 or 1·0 mg DOCA/kg resulted in a mean maximal increase in plasma LH concentration of between 0·47 and 2·10 ng/ml. The magnitude of this response was not related to either the dose or the stage of the cycle at which the DOCA was injected. In the remaining five hens DOCA failed to stimulate LH secretion. Injection of either androstenedione, oestrone or oestradiol did not result in any increase in LH level in the circulation. In contrast, injection of 0·5, 1·0 or 2·0 mg testosterone/kg between 22 and 26 h after the terminal ovulation of a sequence resulted in mean maximal incremental changes in plasma LH level of 1·98 ± 0·17, 2·17 ± 0·21 and 2·41 ± 0·31 (s.e.m.) ng/ml from pre-injection values of 1·38 ± 0·16, 1·58 ± 0·30 and 1·43 ± 0·39 ng/ml (n = 7, 6 and 5, respectively). The interval between the injection and the resulting rise in LH level was inversely proportional to the dose. The same doses of testosterone injected between 0 and 8 h after ovulation failed to stimulate LH secretion. There was also no significant increase in LH levels after injection of 0·5 and 1·0 mg testosterone/kg between 8 and 9 h after ovulation. However, injection of 2 mg testosterone/kg at this time resulted in a small but significant (P < 0·05) increase in LH levels. Since the largest ovarian follicle is more mature at 22–26 h after ovulation than at 0–9 h after ovulation, the ability of testosterone to cause the release of LH therefore appears to depend upon the degree of maturation of the ovarian follicle next due to ovulate.

Diurnal changes in the plasma concentrations of LH and hypothalamic contents of LHRH-I and LHRH-II in the domestic hen

1991 ◽  
Vol 130 (3) ◽  
pp. 457-462 ◽  
Author(s):  
S. C. Wilson ◽  
R. T. Gladwell ◽  
F. J. Cunningham
Keyword(s):  
Plasma Concentration ◽  
Diurnal Rhythm ◽  
Laying Hens ◽  
Plasma Concentrations ◽  
Posterior Hypothalamus ◽  
Anterior Hypothalamus ◽  
Diurnal Changes ◽  
The Mean ◽  
The Times ◽  
Lh Secretion

ABSTRACT Diurnal changes of LH secretion in sexually immature hens of 9, 11, 13 and 15 weeks of age consisted of 25–40% increases in the mean concentrations of LH in plasma between 15.00 and 18.00 h, i.e. between 2 h before and 1 h after the onset of darkness. During this time there was a tendency for the mean contents of LHRH-I in the anterior hypothalamus and posterior hypothalamus to increase by 21–74% and 20–56% respectively. In hens of 9 and 15 weeks, diurnal changes in the plasma concentration of LH closely paralleled those of LHRH-I content in the posterior hypothalamus. In contrast, the diurnal rhythm of LH secretion in hens of 11 and 13 weeks was more marked and plasma concentrations of LH continued to rise steeply between 18.00 and 21.00 h, i.e. between 1 and 4 h after the onset of darkness. At 11 weeks, this was associated with a reduction (P<0·01) in the contents of LHRH-I and LHRH-II, particularly in the anterior hypothalamus. In laying hens, a diurnal decline (P<0·01) in the plasma concentration of LH between 1 and 4 h after the onset of darkness was preceded by a fall (P<0·05) in the content of LHRH-I in the posterior hypothalamus and in the total hypothalamic content of LHRH-II (P<0·01). In all groups of hens, irrespective of the times of day at which tissue was taken, significant (P<0·05–<0·001) correlations between the contents of LHRH-I and LHRH-II in the anterior hypothalamus were observed. It is concluded that a diurnal rhythm of release of LHRH-I may drive the diurnal rhythm of LH secretion. Thus, in sexually immature hens of 9 and 15 weeks and laying hens in which diurnal changes in plasma LH were small there were parallel changes in the content of LHRH-I in the posterior hypothalamus. However, where the plasma concentration of LH was increased substantially, as at 11 weeks, there was a decline in the hypothalamic contents of LHRH-I. A simultaneous fall in the hypothalamic content of LHRH-II raises the possibility of a causal relationship between the activities of LHRH-II, LHRH-I and the release of LH. Journal of Endocrinology (1991) 130, 457–462

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.

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.

An investigation of diurnal and cyclic changes in the secretion of luteinizing hormone in the domestic hen

1983 ◽  
Vol 98 (1) ◽  
pp. 137-145 ◽  
Author(s):  
S. C. Wilson ◽  
R. C. Jennings ◽  
F. J. Cunningham
Keyword(s):  
Luteinizing Hormone ◽  
Diurnal Rhythm ◽  
Laying Hen ◽  
Ovulatory Cycle ◽  
Pronounced Increase ◽  
Threefold Increase ◽  
Steep Decline ◽  
Cyclic Changes ◽  
Lh Secretion ◽  
Domestic Hen

The characteristics of the diurnal rhythm in the concentration of LH in plasma of the domestic hen varied according to age and duration of photoperiod. A pronounced increase in LH was observed at the onset of darkness in immature hens whether maintained on schedules of 16 h light:8 h darkness (16L:8D) or 8L:16D. During weeks 4·5–15 or −17·5 raised concentrations of LH were maintained until 6 and 12 h after the onset of darkness in hens held on 16L:8D and 8L:16D respectively. By 19 weeks of age the diurnal rhythm of LH secretion had changed to resemble more closely that observed in the laying hen. An increase in the concentration of LH in plasma at the onset of darkness was of comparatively short duration and gave way, within 2–3 h, to a steep decline before a further slight increase in LH, which tended to occur at 11–14 h after the onset of darkness. Superimposed on this diurnal rhythm of LH secretion in the laying hen were a one- to threefold increase in the concentration of LH during 8–4 h before ovulation and a much less pronounced increase in LH during 0–8 h after ovulation. The pattern of changes in the concentration of LH in plasma during the ovulatory cycle was not modified by the repeated withdrawal of blood at intervals of 2 h.

scholarly journals PSXIII-42 Plasma levels of growth hormone in laying hens in relation to developmental and hormonal factors

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 367-368
Author(s):  
Araksiya A Smekalova ◽  
Irina Lebedeva ◽  
Nahid Parvizi ◽  
Roland Grossmann
Keyword(s):  
Growth Hormone ◽  
Plasma Levels ◽  
Ovarian Function ◽  
Laying Hens ◽  
Plasma Concentrations ◽  
Average Concentration ◽  
Reproductive Status ◽  
Ovulatory Cycle ◽  
Ovarian Steroid ◽  
Reproductive Impairment

Abstract Growth hormone (GH) is an important positive regulator of ovarian function in vertebrates, including birds, but it can accelerate aging processes. In the present study, GH levels in the blood of laying hens were investigated due to age, reproductive status and ovulatory cycle-related hormones. To this end, the following groups of hens were used: (1) young hens with long clutch (YLC, 29–31 week-old, &gt;10 eggs per clutch), (2) YLC hens treated with LH (YLC-LH), (3) old hens with long clutch (OLC, 62–64 week-old), (4) old hens with short clutch (OSC, 3–6 eggs per clutch). The hens were sacrificed at 1.5 or 14.5 h after assumed ovulation as well as 3.5 h after the LH injection (n = 5–6 per each group). Plasma concentrations of GH were determined by RIA and those of ovarian steroid hormones were measured by ELISA. The data were analyzed by ANOVA. In all compared groups, levels of GH were similar at the beginning and the middle of the ovulatory cycle. The average concentration of GH in OSC hens was higher than in OLC hens (1.28±0.38 vs 0.39±0.09 ng/ml, P &lt; 0.05) but did not differ from that in YLC hens (0.76±0.22 ng/ml). Furthermore, in OSC hens, a positive correlation (r=0.84, P &lt; 0.05) was revealed between GH levels and testosterone levels in the middle of the ovulatory cycle. Injections of LH raised ovarian steroid concentrations (P &lt; 0.001) and did not affect GH concentrations in the plasma of YLC hens. Meanwhile, GH levels correlated with estradiol-17β levels in the YLC-LH group (r=0.81, P &lt; 0.05). The findings suggest that elevated plasma levels of GH are associated with a reproductive impairment in old hens. Besides, a relationship between GH and ovarian steroids depends on the hen age, reproductive status, ovulatory cycle stage, and LH impact. The study was supported partly by RFBR (19-016-00216).

Short-term kinetics of LRH-induced LH-release in the long-term ovariectomized rat

1982 ◽  
Vol 99 (2) ◽  
pp. 187-194 ◽  
Author(s):  
T. R. Koiter ◽  
N. Pols-Valkhof ◽  
G. A. Schuiling
Keyword(s):  
Luteinizing Hormone ◽  
Initial Phase ◽  
Plasma Concentrations ◽  
Compartment Model ◽  
Ovx Rats ◽  
Lh Release ◽  
Series Of Experiments ◽  
Lh Secretion ◽  
Very High

Abstract. In a first series of experiments plasma concentrations of luteinizing hormone (LH) were measured at 10 min intervals during 2 h of constant rate infusion of luteinizing hormone-releasing hormone (LRH; 104 ng/ h) in phenobarbitone-anaesthetized long-term ovariectomized (OVX) rats, treated with oil or oestradiol-benzoate (OeB). From these data the mean LH secretion rates during the sampling intervals were calculated using a one-compartment model for the elimination of LH from the plasma. It was found in the OeB-primed OVX rats that during the initial 30–40 min of infusion the LH release is high but constant. Thereafter it shows a further increase. In the oil-treated OVX rats a similar biphasic LH release pattern was found, but in these animals it was preceded by an initial phase of very high LH release, lasting a few minutes. In another series of experiments a second LRH infusion (again 104 ng/h) was given to OeB-primed OVX rats, starting 1.5 h after the discontinuation of a first LRH infusion lasting either 1, 3.5 or 20 h. The resulting secondary LH responses were smaller the longer the first infusion had lasted, but the LH secretion pattern was similar with all three time schedules and resembled the triphasic pattern observed during the first experiment in the oil-treated OVX rats, rather than the biphasic pattern of the OeB-primed OVX rats. These results indicate that the LH response to LRH of OVX rats (either treated with OeB or oil), like that of the cyclic rats, exhibits a phase of constant LH release. It is generally assumed that during this period conditions, necessary for the subsequent further increase of the LH secretion, are generated. It is concluded that these conditions largely disappear during a 1.5 h non-stimulus period. It is also concluded that the short initial phase of very high LH secretion is due to recent exposure of the LH-secretory system to stimulatory amounts of LRH.

CHANGES IN THE CONCENTRATIONS OF OESTRONE AND OESTRADIOL IN THE PERIPHERAL PLASMA OF THE DOMESTIC HEN DURING THE OVULATORY CYCLE

1974 ◽  
Vol 77 (3) ◽  
pp. 588-596 ◽  
Author(s):  
B. E. Senior
Keyword(s):  
Luteinizing Hormone ◽  
Laying Hens ◽  
Peak Level ◽  
Ovulatory Cycle ◽  
Blood Samples ◽  
Expected Time ◽  
Peripheral Plasma ◽  
Significant Change ◽  
Domestic Hen

ABSTRACT The concentrations of oestrone and oestradiol were measured by radioimmunoassay in the peripheral plasma of hens during the ovulatory cycle and of non-laying hens. During the ovulatory cycle when blood samples were taken at 4 or 6 h intervals for 24 h, the peak concentrations of oestrone and oestradiol occurred within the 6 h period immediately preceding ovulation. After the final ovulation of the clutch the oestradiol concentration fell gradually and did not rise again near the time when the last egg of the clutch was laid. There was no significant change in the concentration of oestradiol over a 24 h period in non-laying hens. When blood samples were taken at 2 h intervals during the 12–14 h period before the expected time of ovulation the oestradiol concentration rose 8 h before ovulation and reached a peak level 6–4 h beforehand. It is suggested that oestradiol may be involved in the mechanism stimulating the release of luteinizing hormone required for ovulation.

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