SEXUAL DIFFERENTIATION OF THE PHOTOPERIODIC RESPONSE IN JAPANESE QUAIL

1982 ◽  
Vol 92 (2) ◽  
pp. 279-282 ◽  
Author(s):  
H. F. URBANSKI ◽  
B. K. FOLLETT

Plasma levels of LH are generally higher in male than in female quail. This dimorphism was found to persist in quail which had been through a breeding cycle and then gonadectomized. Under long daylengths (12 h light: 12 h darkness (12L : 12D) or 16L : 8D) ovariectomized quail had plasma levels of LH that were 55–70% of those seen in castrated birds. The difference was reduced after transfer to short days (8L : 16D) when LH concentrations fell to basal levels, but again became more pronounced when the quail were restimulated with long photoperiods. Thus, the photoperiodic response system is sexually differentiated.

1982 ◽  
Vol 92 (1) ◽  
pp. 73-83 ◽  
Author(s):  
H. F. URBANSKI ◽  
B. K. FOLLETT

Male Japanese quail were castrated when sexually immature and immediately exposed to one of the following stimulatory lighting regimes for 52 days: 11 h light: 13 h darkness/day (11L : 13D), 12L : 12D, 13L : 11D, 14L : 10D, 15L : 9D, 16L : 8D, 20L : 4D or 23L : 1D. One group was retained on short days (8L : 16D). Clearcut differences in the plasma levels of LH and FSH emerged between the various groups. Levels remained very low in castrated quail on 8L : 16D but were much greater in those on 14L : 10D, 15L : 9D, 16L : 8D, 20L : 4D and 23L : 1D, eventually becoming 15 to 20 times higher. Less pronounced castration responses developed on 13L : 11D, 12L : 12D or 11L : 13D. Alterations in photoperiod after day 52 caused an appropriate rise or fall in LH secretion. Photoperiodically induced suppressions were rapid, being highly significant within 4 days, but increases usually had a slower time course. When sexually mature quail (on 16L : 8D) were castrated and transferred to 8L : 16D they also exhibited a rapid suppression in LH secretion. Thus in quail, unlike some mammals, the photoperiodic control over gonadotrophin secretion is independent of the reproductive status of the animal at the time of castration. The results confirm the view that changes in sensitivity of the hypothalamo-pituitary axis to gonadal steroids are not a primary factor in the neural mechanisms underlying photoperiodism in quail.


1977 ◽  
Vol 74 (3) ◽  
pp. 355-367 ◽  
Author(s):  
G. A. LINCOLN ◽  
M. J. PEET

SUMMARY Six adult Soay rams were housed under artificial lighting conditions of long days (16 h light: 8 h darkness) for 4 months and this caused the animals to lapse into a state of reproductive quiescence with low levels of gonadotrophins in the circulation and regressed testes secreting very low amounts of testosterone. The photoperiod was changed abruptly to short days (8 h light: 16 h darkness) to induce a resurgence of sexual activity, and a detailed study was made of the pituitary and testicular responses over the first 100 days. Plasma levels of LH and FSH first began to increase between days 6 and 12 of short days, and rose progressively until days 33–54 before declining again. Testicular growth of the rams began on days 19–26 and continued for most of the remaining period of study. Plasma testosterone levels rose in parallel with the growth of the testes, and were greatly increased by day 100 when gonadotrophin levels were reduced. At most stages there were short-term fluctuations in the plasma levels of FSH, LH and testosterone indicative of episodic secretion. Peaks in plasma levels of LH were especially conspicuous and from the changes in frequency and amplitude of these peaks it was possible to predict the way in which photoperiod influenced gonadotrophin secretion by its effect on hypothalamic LH-RH secretion. A slight 24 h rhythm in the plasma levels of all three hormones was observed, and the significance of this in relation to the photoperiodic response is discussed.


1979 ◽  
Vol 83 (3) ◽  
pp. 323-330 ◽  
Author(s):  
D. J. HEAF ◽  
J. GLOVER

In a single experiment, lasting for 18 months, male and female quail were exposed to an annual cycle of artificial photoperiod synchronized with sunrise and sunset, and their plasma levels of immunoreactive retinol-binding protein (IRBP) and LH were monitored at frequent intervals. Plasma levels of both IRBP and LH showed a repeating annual cycle with maximal levels during the spring/summer, the period of reproductive activity and highest rate of egg-laying, and minimal levels during the autumn/winter. Plasma levels of IRBP and LH were significantly, but only weakly, correlated with each other. The possible role of LH in the regulation of plasma IRBP during reproduction is discussed. Evidence is presented that the proportion of IRBP which does not carry retinol (retinol-binding apoprotein; apoRBP) varies throughout the female breeding cycle and that the high apoRBP concentration noted in the spring/summer period may be related to the deposition of retinol in the egg.


1975 ◽  
Vol 64 (1) ◽  
pp. 87-101 ◽  
Author(s):  
W. R. GIBSON ◽  
B. K. FOLLETT ◽  
BARBARA GLEDHILL

SUMMARY Plasma levels of luteinizing hormone (LH) were measured by radioimmunoassay in gonadectomized male and female Japanese quail, exposed either to 8 h light: 16 h darkness per day (8L:16D; short days) or to 20L:4D (long days). In both sexes, exposure to long days increased LH levels and in the gonadectomized quail LH continued to rise over several weeks. Eventually the castrated quail had levels about five times higher than the control birds and the ovariectomized quail had levels about 14 times higher than their controls. Quail kept on short days had low LH levels while birds kept on long days and returned to short days resumed low levels after a delay of some days. Since very high levels of LH occurred in gonadectomized quail only when they were on long days, we conclude that the photoperiodic regulation of LH secretion does not operate solely by adjusting sensitivity to gonadal feedback, but works in a more direct manner. Ovariectomized females whether on long days (high LH) or short days (low LH) grew masculine plumage and castrated males retained male plumage. This confirms that the ovary is responsible for sexual dimorphism of plumage and shows that the action of the ovary is not mediated by LH (through feedback). The remaining rudimentary (right) gonad in ovariectomized females did not undergo visible hypertrophy and did not secrete enough hormone to stimulate the cloacal gland or oviduct.


1984 ◽  
Vol 52 (03) ◽  
pp. 236-239 ◽  
Author(s):  
J Fritschi ◽  
M Christe ◽  
B Lämmle ◽  
G A Marbet ◽  
W Berger ◽  
...  

SummaryWe have studied 155 subjects, 48 normals, 36 diabetics without complications, 44 with complications and 27 patients with macroangiopathy. β-Thromboglobulin (β-TG) and platelet factor 4 (PF4) are elevated in the patients groups. There is no correlation between the plasma levels of β-TG and the stages of either retinopathy or macroangiopathy or nephropathy. The difference is more marked between normals and diabetics with neuropathy (p = 0.026). The aggregation response to ADP and platelet activating factor (PAF) is enhanced at lower stimulator concentration. Using the β-TG, PF4 and aggregation values the discriminant analysis allows a distinction of several subgroups especially with nephropathy and neuropathy (Table 6).


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hongseok Yoo ◽  
Yunjoo Im ◽  
Ryoung-Eun Ko ◽  
Jin Young Lee ◽  
Junseon Park ◽  
...  

AbstractThe role of high-mobility group box-1 (HMGB1) in outcome prediction in sepsis is controversial. Furthermore, its association with necroptosis, a programmed cell necrosis mechanism, is still unclear. The purpose of this study is to identify the association between the plasma levels of HMGB1 and the severity and clinical outcomes of sepsis, and to examine the correlation between HMGB1 and key executors of necroptosis including receptor-interacting kinase 3 (RIPK3) and mixed lineage kinase domain-like- (MLKL) proteins. Plasma HMGB1, RIPK3, and MLKL levels were measured with the enzyme-linked immunosorbent assay from the derivation cohort of 188 prospectively enrolled, critically-ill patients between April 2014 and December 2016, and from the validation cohort of 77 patients with sepsis between January 2017 and January 2019. In the derivation cohort, the plasma HMGB1 levels of the control (n = 46, 24.5%), sepsis (n = 58, 30.9%), and septic shock (n = 84, 44.7%) groups were significantly increased (P < 0.001). A difference in mortality between high (≥ 5.9 ng/mL) and low (< 5.9 ng/mL) HMGB1 levels was observed up to 90 days (Log-rank test, P = 0.009). There were positive linear correlations of plasma HMGB1 with RIPK3 (R2 = 0.61, P < 0.001) and MLKL (R2 = 0.7890, P < 0.001). The difference in mortality and correlation of HMGB1 levels with RIPK3 and MLKL were confirmed in the validation cohort. Plasma levels of HMGB1 were associated with the severity and mortality attributed to sepsis. They were correlated with RIPK3 and MLKL, thus suggesting an association of HMGB1 with necroptosis.


1988 ◽  
Vol 24 (2) ◽  
pp. 237-245
Author(s):  
Serpil Terzioğlu

SUMMARYThe vernalization and photoperiodic response of six locally adapted bread wheat cultivars grown under natural daylength conditions during the summer or winter months was examined in glasshouse experiments. The wheat was vernalized by chilling imbibed grains at 2 ± 1°C for 0, 15 or 45 days. Vernalization for 45 days followed by long summer days led to floral initiation in all cultivars within 28 days but vernalization for 0 or 15 days only led to floral initiation in one cultivar. Vernalization followed by long days reduced the time from transplanting to anthesis, resulting in early ear emergence. Vernalization followed by short days accelerated the development of all the cultivars, but normal development could also occur without vernalization at this time of year. Apical differentiation of the primary shoot and its length and development gave the most reliable information on the period of vernalization required.


1970 ◽  
Vol 63 (4) ◽  
pp. 705-716 ◽  
Author(s):  
U. Larsson-Cohn ◽  
E. D. B. Johansson ◽  
L. Wide ◽  
C. Gemzell

ABSTRACT Daily determinations of the plasma level of progesterone and the urinary excretion of luteinizing hormone (LH) and total oestrogens were performed in 6 subjects during one control cycle, immediately followed by three cycles of daily treatment with 0.5 mg of chlormadinone acetate continuously. The control cycles were ovulatory according to the parameters investigated. Two of the women showed a normal LH excretion pattern in all treatment cycles. The four other subjects also had periodical variations in the LH excretion but no distinct midcycle peaks occurred. The mean oestrogen excretion was increased in all three treatment cycles but the difference was satistically significant only in the last two cycles. Compared with the treatment cycles, the sum of progesterone values was significantly decreased in the first two cycles. Chlormadinone acetate in this dose had no thermogenic effect. Three of the subjects showed bleeding irregularities which had no clear connection with the hormone variations measured in the study. It is suggested that the low levels of progesterone might be due to a defective corpus luteum function.


Author(s):  
Shinji Tsukahara ◽  
Masahiro Morishita ◽  
Shiho Sasaki ◽  
Kanta Wakayama ◽  
Kaito Kobayashi ◽  
...  

1959 ◽  
Vol 5 (6) ◽  
pp. 557-565 ◽  
Author(s):  
Harold D Appleton ◽  
Alvin F Coburn ◽  
Yale L Meltzer

Abstract Three phospholipid fractions have been determined in plasmas of quiescent rheumatic children and their siblings of similar ages. The method for determining blood lecithin gave reproducible results, and the lipid fraction appeared indicative of difference in levels of blood lipids between rheumatic and nonrheumatic children. In this series of lecithin determinations only one rheumatic subject had a high normal level and only one sibling (presumably nonrheumatic) had a low level. The difference in mean nonfasting lecithin plasma levels between rheumatic subjects and siblings was 0.36 mMol./L. Similarly, the lecithin level of each of the nonrheumatic siblings in this series averaged 0.41 mMol./L. higher than that of the corresponding quiescent rheumatic child. In both of these differences P &lt;0.05.


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