EFFECT OF PHOTOPERIOD ON THE CONCENTRATIONS OF CORTICOSTERONE AND LUTEINIZING HORMONE IN THE PLASMA OF THE DOMESTIC HEN

1981 ◽  
Vol 91 (1) ◽  
pp. 135-143 ◽  
Author(s):  
SUSAN C. WILSON ◽  
F. J. CUNNINGHAM
Keyword(s):  
Plasma Concentration ◽  
Luteinizing Hormone ◽  
Continuous Light ◽  
Significant Rise ◽  
Maximal Concentration ◽  
Pronounced Increase ◽  
Circadian Periodicity ◽  
Free Running ◽  
Domestic Hen

Ovipositions in hens maintained under schedules of 16 h light: 8 h darkness (16L : 8D) or 8L : 16D were restricted to a 12 h period of the day while in hens maintained on continuous light, ovipositions occurred at times throughout the whole of the 24 h day. In hens maintained in continuous light a significant rise in the plasma concentration of corticosterone was observed 11–9 h before ovulation/oviposition. In hens in 16L : 8D there was an increase in the concentration of corticosterone in the plasma during the first 1·5 h of darkness which, under that schedule, coincides with the onset of the 'open period' for the occurrence of the preovulatory release of LH. In hens ovulating the first egg of a sequence the rise in the secretion of corticosterone was only transient and levels fell as preovulatory concentrations of LH rose to a peak. However, in hens undergoing an ovulation late in a sequence or in those not expected to ovulate, the concentration of corticosterone in the plasma continued to rise to attain a maximal concentration 8 h later. In hens maintained in 8L : 16D there was a tendency for the concentration of corticosterone in the plasma to increase at the beginning of the open period, 4 h after the onset of darkness, though this rise was much smaller than that observed at the beginning of the open period of hens on 16L : 8D. A further, more pronounced, increase in the concentration of corticosterone was observed between 11 and 15 h after the onset of darkness. It is suggested that the rise in the concentration of corticosterone at 11–9 h before ovulation in hens in continuous light reflects the beginning of an open period with a free-running circadian periodicity of 26–27 h.

Concentrations of luteinizing hormone and progesterone in plasma during sexual development of the Khaki Campbell duck

1982 ◽  
Vol 93 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Susan C. Wilson ◽  
T. R. Morris
Keyword(s):  
Plasma Concentration ◽  
Luteinizing Hormone ◽  
Negative Correlation ◽  
Sexual Development ◽  
Plasma Concentrations ◽  
Winter Solstice ◽  
Pronounced Increase ◽  
Threefold Increase ◽  
Lh Release

Concentrations of LH and progesterone were measured in the plasma of ducks which were, from 3 weeks of age, raised on either a constant photoperiod of 16 h light: 8 h darkness or a lighting schedule which simulated natural changes in daylength. In ducks raised on a constant photoperiod of 16 h light: 8 h darkness the plasma concentration of LH increased steeply between 7 and 3·5 weeks before the onset of lay. Concentrations of LH then declined, gradually at first, but then rapidly during the 7 days before the first oviposition in association with a pronounced increase in the plasma concentration of progesterone. During the 18 days before the first egg was laid there was a significant (P < 0·01) negative correlation between the plasma concentrations of LH and progesterone. The patterns of LH release during sexual development of ducks raised on a schedule which simulated natural changes in daylength were variable but could be categorized according to the daylength at which each duck came into lay. In ducks coming into lay soon after the winter solstice when daylength was short (8·0–8·5 h light/day) there was a pronounced 15-fold prepubertal increase in the plasma concentration of LH although in some ducks high LH levels were not maintained until 3–4 weeks before the first oviposition and were not always followed by a rise in the plasma concentration of progesterone. In contrast, in ducks coming into lay when daylength had increased to 11·0–11·5 h light/day there were only minor fluctuations in the plasma concentration of LH until a small two- to threefold increase in LH was observed during the 2 weeks before the first oviposition.

Evidence of a photoinducible phase for the release of luteinizing hormone in the domestic hen

1982 ◽  
Vol 94 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Susan C. Wilson
Keyword(s):  
Plasma Concentration ◽  
Luteinizing Hormone ◽  
Control Group ◽  
Abrupt Increase ◽  
Threefold Increase ◽  
Main Period ◽  
Lh Release ◽  
Lh Releasing Hormone ◽  
Lh Secretion ◽  
Domestic Hen

Hens raised on a schedule of 8 h light: 16 h darkness (8L : 16D) were exposed to changes in photoperiod at 17 or 18 weeks of age. These involved exposure to either an abrupt increase in photoperiod to 16 h per day or to skeleton photoperiods comprising a main period of 7·75 or 4 h light together with a pulse of 15 min or 4 h light provided at different times during the period of darkness. An increase in photoperiod to 16 h per day stimulated a two- to threefold increase in the plasma concentration of LH within 1–3 days. Interruption of a 7·75L : 16D schedule by 15 min light between 13·75 and 19·75 h after the beginning of the main photoperiod stimulated LH secretion in the immature and adult hen and a higher rate of lay than that of the 8L : 16D control group. There was a significant (P < 0·01) correlation between the concentration of LH in the plasma and the rate of lay. The photostimulated rise in the plasma concentration of LH in the immature hen was not associated with any increase in the responsiveness of the pituitary gland to LH releasing hormone. Of the treatments in which a 15-min pulse of light was provided, the schedules of 7·75L : 10D : 0·25L : 6D and 7·75L : 12D : 0·25L : 4D, which were most effective in stimulating LH release, appeared to be interpreted as 0·25L : 6D : 7·75L : 10D and 0·25L : 4D : 7·75L : 12D respectively. In hens given a 7·75-h main photoperiod, in which phase-reversal did not occur, 15 min light was most stimulatory when given 14–16 h after the begining of the main photoperiod, although not to the same extent as an increase in photoperiod to 16 h per day. In hens for which an 8-h complete photoperiod was changed to a 4-h main photoperiod, together with a further 4-h pulse of light provided at different times during the period of darkness, the period of maximum sensitivity to light occurred 11 h after the onset of the main photoperiod and at this time light stimulated LH release to the same extent as an increase in complete photoperiod from 8 to 16 h per day. Results of this study suggest that the period of maximum photosensitivity shifts its phase after a change in the form of photoperiod and is primarily entrained to dusk.

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.

Developmental changes in the diurnal rhythm of secretion of corticosterone and LH in the domestic hen

1984 ◽  
Vol 101 (3) ◽  
pp. 299-304 ◽  
Author(s):  
S. C. Wilson ◽  
R. C. Jennings ◽  
F. J. Cunningham
Keyword(s):  
Plasma Concentration ◽  
Phase Angle ◽  
Diurnal Rhythm ◽  
Sexual Development ◽  
Plasma Concentrations ◽  
Transient Increase ◽  
Developmental Changes ◽  
Diurnal Changes ◽  
Pronounced Increase ◽  
Domestic Hen

ABSTRACT When diurnal changes in the plasma concentrations of corticosterone and LH were compared at various times during sexual development a diurnal rhythm in the secretion of corticosterone was most pronounced at 4·5 weeks of age in hens maintained on a schedule of 8 h light: 16 h darkness (8L: 16D) and at 8·5 weeks of age in hens maintained on 16L: 8D. At these ages the phase-angle of the rhythm in relation to the onset of darkness was 3 h earlier than had been observed in previous studies of the adult hen. The characteristics of the corticosterone rhythm changed during sexual development and diurnal changes were no longer evident in hens at 17 weeks of age at a time when prepubertal plasma concentrations of LH were maximal. However, there was a tendency for plasma concentrations of corticosterone to fluctuate diurnally in hens studied at less than 10 days before the onset of lay although not to the same extent as has previously been observed in the adult hen. This period of development was associated with a pronounced increase in the plasma concentration of progesterone. An increase in the plasma concentration of LH at the onset of darkness was observed at all ages in hens maintained on either photoschedule. In hens of 4·5–15 weeks of age maintained on 16L:8D or 8L:16D this increase in the plasma concentration of LH was sustained during the first 5 or 8–11 h of darkness respectively but at 17 weeks of age only a transient increase in LH was seen at the onset of darkness. Plasma concentrations of LH in samples of plasma taken at intervals of between 3 days and 2 weeks throughout sexual development were, until 18–19 weeks, consistently higher in hens maintained on a photoschedule of 16L:8D than on 8L: 16D. J. Endocr. (1984) 101, 299–304

CHANGES IN THE CONCENTRATION OF LUTEINIZING HORMONE IN PLASMA DURING DEVELOPMENT IN THE GUINEA-PIG

1975 ◽  
Vol 64 (3) ◽  
pp. 511-520 ◽  
Author(s):  
B. T. DONOVAN ◽  
M. B. TER HAAR ◽  
A. N. LOCKHART ◽  
P. C. B. MACKINNON ◽  
J. M. MATTOCK ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Luteinizing Hormone ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Plasma Concentrations ◽  
Maternal Plasma ◽  
Significant Rise ◽  
Cross Reaction ◽  
Blood Collection ◽  
Postnatal Life

SUMMARY The concentration of LH in the plasma of guinea-pigs from day 50 of gestation to day 45 of postnatal life was assayed by radioimmunoassay utilizing a cross-reaction with anti-ovine LH antiserum. The effect of gonadectomy in infancy and in the adult upon the plasma concentration of LH was also studied. The LH concentration in the plasma of male or female foetuses was high immediately prenatally and fell at birth. High levels of LH were again detected in male, with a lesser increase in female, guinea-pigs over the first 10 days postnatally. Maternal plasma concentrations of LH remained consistently low. Removal of the gonads on days 0, 5, 10, 15, 25 or 35 of postnatal life, followed by blood collection at autopsy 10 days later, caused a significant rise in plasma LH content at all ages. The rise in plasma LH after gonadectomy in adults was less marked in male than in female guinea-pigs.

In vivo acute testicular testosterone response to injection of luteinizing hormone in the rat fetus

1993 ◽  
Vol 128 (3) ◽  
pp. 268-273 ◽  
Author(s):  
René Habert
Keyword(s):  
Plasma Concentration ◽  
Luteinizing Hormone ◽  
Leydig Cells ◽  
Time Dependent ◽  
Fetal Life ◽  
Dependent Manner ◽  
Adult Rats ◽  
Rat Fetus ◽  
Age Related

The acute in vivo testosterone response to LH stimulation and its change during late fetal life were determined in the rat. In 18.5-day-old fetuses, testicular testosterone content was increased in a dose-and time-dependent manner after fetal subcutaneous LH injection. The maximum response was small: the testicular content and plasma concentration were increased by 200% and 2 50% over basal values respectively, while they were increased 1100% and 1200% in adult rats. Similarly, comparable low responses were obtained after subcutaneously injecting the fetuses with human chorionic gonadotropin (hCG) and after injecting LH into the vitelline vein. Between days 18.5 and 21.5 of fetal life, the testosterone levels in the testis and plasma of uninjected or PBS-injected fetuses decreased and were comparable in both groups. In maximally LH-stimulated fetuses, the testicular content did not change with age, and plasma concentration was lower on day 21.5 than on day 18.5. Since the number of Leydig cells increases 1.5 to 2-fold between days 18.5 and 21.5, these results show an age-related decrease in basal and maximally LH-stimulated in vivo testosterone secretions per Leydig cell during late fetal life.

PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE, TESTOSTERONE AND ANDROSTENEDIONE IN CASTRATED AND ADRENALECTOMIZED BULL CALVES

1978 ◽  
Vol 79 (1) ◽  
pp. 137-138 ◽  
Author(s):  
J. J. BASS ◽  
A. J. PETERSON ◽  
E. PAYNE
Keyword(s):  
New Zealand ◽  
Plasma Concentration ◽  
Luteinizing Hormone ◽  
Agricultural Research ◽  
Plasma Concentrations ◽  
Young Male ◽  
Research Centre ◽  
Similar Magnitude ◽  
Research Division ◽  
Bull Calves

Ministry of Agriculture and Fisheries, Research Division, Ruakura Agricultural Research Centre, Hamilton, New Zealand (Received 17 April 1978) An increase in the plasma concentration of luteinizing hormone (LH) occurs in response to castration in bull calves aged 1–4 months; this response is of similar magnitude to that seen in cattle castrated as adults (Odell, Hescox & Kiddy, 1970). In bull calves castrated at birth, however, there is no increase in the plasma concentration of LH until after 28 days of age (Bass, Peterson, Payne & Jarnet, 1977). In other species a range of responses to castration has been reported. Gonadectomy of male guinea-pigs 0–35 days after birth produces an increase in the plasma concentration of LH similar to that observed in guineapigs castrated as adults (Donovan, ter Haar, Lockhart, MacKinnon, Mattock & Peddie, 1975). In contrast, the castration of young male macaques does not cause an immediate increase in the

scholarly journals Photoperiodic modulation of circadian rhythms in the silk gland protein profiles of Bombyx mori and its influence on the silk productivity and quality

2010 ◽  
Vol 2 (1) ◽  
pp. 48-56 ◽  
Author(s):  
B. Sailaja ◽  
S. Sivaprasad
Keyword(s):  
Circadian Rhythms ◽  
Bombyx Mori ◽  
Continuous Light ◽  
Silk Gland ◽  
Protein Profiles ◽  
Dark Cycle ◽  
Response Curves ◽  
Silk Proteins ◽  
Free Running ◽  
Clock Shift

Circadian rhythms in the silk gland protein profiles of Bombyx mori were analyzed under 12 h light and 12 h dark cycle (LD), continuous light (LL) and continuous dark (DD) conditions. The phase response curves of protein rhythms indicate the prevalence of a series of silk cycles, each comprising three phases; transcription, translation and consolidation of silk proteins. In the 24h- protein rhythm, the silk cycle repeats every 3h, 42 m under LD, 2h, 36m under LL and 3h under DD. The light and dark conditions advanced the rhythm of each silk cycle by 48m and 24m respectively. As a result the silk gland completes 7 rounds of protein synthesis under LD, 9 rounds under LL and 8 rounds under DD during the 24h-free running time of the rhythm. The light-induced clock-shift in the protein rhythm caused significant gains in economic parameters of sericulture with positive signals for enhancing silk productivity and quality.

Splitting of the locomotor activity rhythm in rats by exposure to continuous light

1983 ◽  
Vol 244 (4) ◽  
pp. R573-R576 ◽  
Author(s):  
Phyllis W. Cheung ◽  
Charles E. McCormack
Keyword(s):  
Locomotor Activity ◽  
Estrous Cycle ◽  
Activity Rhythm ◽  
Continuous Light ◽  
Female Rats ◽  
Locomotor Rhythm ◽  
Estrous Cycles ◽  
Locomotor Activity Rhythm ◽  
Active Portion ◽  
Free Running

Female rats exposed to low intensities (0.1–1.5 lx) of continuous light (LL), displayed regular estrous cycles and free-running circadian rhythms of locomotor activity. In most rats, as the intensity of LL was increased to >2.0 lx, components within the active portion (α) of the locomotor rhythm remained synchronized as the periodicity of the rhythm lengthened. However, in a few rats agr split into two components; one of which free-ran with a period shorter than 24 h, while the other free-ran with a period longer than 24 h. As soon as the two components became maximally separated they spontaneously rejoined. In most rats, estrous cycles ceased shortly after the intensity of LL was increased to >2.0 lx even though the locomotor activity rhythm retained its unsplit free-running nature. These observations suggest that the multiple oscillators that control the rhythms of locomotor activity and the estrous cycle are normally coupled to one another. In certain intensities of LL, these oscillators uncouple and free-run with different periodicities, a condition which causes estrous cycles to cease and sometimes produces a split locomotor activity rhythm. circadian rhythm; oscillators; estrous cycle Submitted on November 9, 1981 Accepted on October 11, 1982

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