Gonadal and photoperiodic influences on body mass regulation in adult male and female prairie voles

1996 ◽  
Vol 270 (5) ◽  
pp. R1013-R1018 ◽  
Author(s):  
L. J. Kriegsfeld ◽  
R. J. Nelson
Keyword(s):  
Body Mass ◽  
Mass Gain ◽  
The Body ◽  
Prairie Voles ◽  
Male And Female ◽  
Short Day ◽  
Body Mass Regulation ◽  
Long Day ◽  
Survival And Reproduction ◽  
Short Days

Nontropical animals commonly use the annual change in photoperiod to phase seasonal adjustments that promote survival and reproduction. To cope with the energetic requirements of winter, many rodents alter body mass in anticipation of winter. Photoperiodic adjustments are often mediated by the pineal hormone melatonin; melatonin can exert a primary effect on body mass or secondarily affect body mass by changing blood gonadal steroid levels. The present study sought to determine if prairie voles (Microtus ochrogaster) alter body mass in response to short photoperiods. The role of the gonads in body mass regulation was also assessed. In experiment 1, males housed in short days increased body mass at a greater rate than long-day animals. Gonadectomy enhanced the body mass gain in short-day voles. These data suggest that the gonads contribute to short photoperiod-induced changes in body mass in male voles. In experiment 2, females housed in short days increased body mass at a greater rate than long-day animals, regardless of whether the animals were ovariectomized. Ovariectomy did not affect body mass in either long- or short-day animals, suggesting that the ovaries do not contribute to photoperiod-mediated changes in body mass in female prairie voles. Taken together, these studies suggest that male and female prairie voles use photoperiodic information to time seasonal changes in body mass.

scholarly journals Effect of food on seasonal response in Indian weaver bird (Ploceus philippinus)

2014 ◽  
Vol 15 (3) ◽  
pp. 19-28
Author(s):  
Shikha Malik ◽  
Rohit Kumar Pandey ◽  
Sanjay Kumar Bhardwaj
Keyword(s):  
Body Mass ◽  
Food Group ◽  
The Body ◽  
Day Length ◽  
Plumage Color ◽  
Supplementary Food ◽  
Short Day ◽  
Long Day ◽  
Group 5 ◽  
Group 2

We investigated the effect of normal (adlib) and supplementary food on body mass, testes growth, moult and plumage color in Indian weaver birds. Birds intially were kept under natural day length (NDL) and then exposed to short day lengths (8 h light: 16 h darkness) for at least 2 weeks before being subjected to an experimental regime. They were divided into five groups (n=4 each), groups 1 and 2 were held under SDL (Short day length -8L: 16D), groups 3 and 4 were exposed to LDL (Long daylength-16L: 8D) and simultaneously group 5 held under natural day length, served as control. One group of SDL (Group 2) and LDL (group 3) as well as group 5 (NDL) were fed on grain with supplement proteinaceous food and groups 2 and 4 were fed on adlib food (grain) only. Observations on body mass, testis growth, bodymolt and plumage color were recorded bi weekly. A significant change in the body mass under both photoperiodic groups (SDL; group 2 and LDL; group 4), but the testicular growth was noticed on long day lengths (LDL: 16L: 8D) and control (NDL) group. However the supplement food modulated the testes growth, body molt, beak pigmentation and body plumage regeneration. Early feather regeneration was found in supplementary food group under long day length. It is suggested that the supplementary food, affects the timing of the development of secondary sexual characteristics.

Flowering of Stylosanthes guianensis in controlled temperatures under natural photoperiod

1984 ◽  
Vol 35 (2) ◽  
pp. 219 ◽  
Author(s):  
RL Ison ◽  
LR Humphreys
Keyword(s):  
Floral Initiation ◽  
Minimum Duration ◽  
Stylosanthes Guianensis ◽  
Short Day ◽  
Long Day ◽  
Natural Photoperiod ◽  
Low Levels ◽  
Short Days

Seedlings of Stylosanthes guianensis var. guianensis cv. Cook and cv. Endeavour were grown in naturally lit glasshouses at Brisbane (lat. 27� 30' S.) at 35/30, 30/25 and 25/20�C (day/night), and were sown so as to emerge at 18-day intervals from 18 January to 11 June. Cook behaved as a long day-short day plant, with seedlings emerging after 5 February flowering incompletely or remaining vegetative until the experiment was terminated in mid-October. In the 25/20�C regimen flowering was incomplete in Cook; in Endeavour flowering was delayed but a conventional short-day response was observed. At 35/30�C Endeavour flowering was inhibited in the shortest days of mid-winter, suggesting a stenophotoperiodic response, but short days were confounded with low levels of irradiance. Minimum duration of the phase from emergence to floral initiation was c. 66-70 days in Cook and c. 40-45 days in Endeavour; the duration of the phase floral initiation to flower appearance was linearly and negatively related to temperature.

Photoperiod modulates the effects of norepinephrine on lymphocyte proliferation in Siberian hamsters

2003 ◽  
Vol 285 (4) ◽  
pp. R873-R879 ◽  
Author(s):  
Gregory E. Demas ◽  
Timothy J. Bartness ◽  
Randy J. Nelson ◽  
Deborah L. Drazen
Keyword(s):  
Lymphocyte Proliferation ◽  
Splenic Tissue ◽  
Splenocyte Proliferation ◽  
Short Day ◽  
Siberian Hamsters ◽  
Long Day ◽  
Β Adrenergic Receptors ◽  
Short Days

Siberian hamsters ( Phodopus sungorus) rely on photoperiod to coordinate seasonally appropriate changes in physiology, including immune function. Immunity is regulated, in part, by the sympathetic nervous system (SNS), although the precise role of the SNS in regulating photoperiodic changes in immunity remains unspecified. The goal of the present study was to examine the contributions of norepinephrine (NE), the predominant neurotransmitter of the SNS, to photoperiodic changes in lymphocyte proliferation. In experiment 1, animals were maintained in long [16:8-h light-dark cycle (16:8 LD)] or short days (8:16 LD) for 10 wk, and splenic NE content was determined. In experiment 2, in vitro splenocyte proliferation in response to mitogenic stimulation (concanavalin A) was assessed in spleen cell suspensions taken from long- or short-day hamsters in which varying concentrations of NE were added to the cultures. In experiment 3, splenocyte proliferation was examined in the presence of NE and selective α- and β-noradrenergic receptor antagonists (phenoxybenzamine and propranolol, respectively) in vitro. Short-day animals had increased splenic NE content compared with long-day animals. Long-day animals had higher proliferation compared with short-day animals independent of NE. NE (1 μM) further suppressed splenocyte proliferation in short but not long days. Last, NE-induced suppression of proliferation in short-day hamsters was blocked by propranolol but not phenoxybenzamine. The present results suggest that NE plays a role in photoperiodic changes in lymphocyte proliferation. Additionally, the data suggest that the effects of NE on proliferation are specific to activation of β-adrenergic receptors located on splenic tissue. Collectively, these results provide further support that photoperiodic changes in immunity are influenced by changes in SNS activity.

Hydration status of Greco-Roman wrestlers in an authentic precompetition situation

2013 ◽  
Vol 38 (6) ◽  
pp. 621-625 ◽  
Author(s):  
Vahur Ööpik ◽  
Saima Timpmann ◽  
Andres Burk ◽  
Innar Hannus
Keyword(s):  
Specific Gravity ◽  
Body Mass ◽  
Urine Osmolality ◽  
Mass Gain ◽  
The Body ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Greco Roman ◽  
Reduced Body ◽  
Body Mass Gain

We assessed the urinary indexes of hydration status of Greco-Roman wrestlers in an authentic precompetition situation at the time of official weigh-in (OWI). A total of 51 of 89 wrestlers competing in the Estonian Championship in 2009 donated a urine sample. Questionnaire responses revealed that 27 wrestlers (body mass losers (BMLs)) reduced body mass before the competition, whereas 24 wrestlers (those who do not lose body mass (n-BMLs)) did not. In 42 wrestlers, values of urine specific gravity ≥1.020 and urine osmolality ≥700 mOsmol·kg−1 revealed a hypohydrated status. The prevalence of hypohydration in the BMLs (96%) was higher than in the n-BMLs (67%) (χ2 = 7.68; p < 0.05). The prevalence of serious hypohydration (urine specific gravity >1.030) was 5.3 times greater (χ2 = 8.32; p < 0.05) in the BMLs than in the n-BMLs. In the BMLs, the extent of body mass gain during the 16-h recovery (2.5 ± 1.2 kg) was associated (r = 0.764; p < 0.05) with self-reported precompetition body mass loss (4.3 ± 2.0 kg) and exceeded the body mass gain observed in the n-BMLs (0.7 ± 1.2 kg; p < 0.05). We conclude that hypohydration is prevalent among Greco-Roman wrestlers at the time of OWI. The prevalence of hypohydration and serious hypohydration is especially high among wrestlers who are accustomed to reducing body mass before competition. These results suggest that an effective rehydration strategy is needed for Olympic-style wrestlers, and that changes in wrestling rules should be considered to reduce the prevalence of harmful body mass management behaviours.

scholarly journals Photoperiodic Response of Peanut Species1

1983 ◽  
Vol 10 (2) ◽  
pp. 59-62 ◽  
Author(s):  
H. T. Stalker ◽  
J. C. Wynne
Keyword(s):  
North Carolina ◽  
Day Treatment ◽  
Photoperiodic Response ◽  
Reproductive Capacity ◽  
Arachis Species ◽  
Short Day ◽  
The North ◽  
Long Day ◽  
Wild Peanut ◽  
Short Days

Abstract Many Arachis species collections do not produce pegs in North Carolina even though they flower profusely. To investigate reasons for the failure of fruiting, nine wild peanut species of section Arachis and three A. hypogaea cultivars representing spanish, valencia and virginia types were evaluated for response to short and long-day treatments in the North Carolina State Phytotron Unit of the Southeastern Environmental Laboratories. The objective of this investigation was to determine the flowering and fruiting responses of Arachis species to short and long-day photoperiods. Plant collections grown under a 9-hour short-day treatment were generally less vigorous, but produced more pegs than corresponding plants grown in long-day treatments which were produced by 9 hours of light plus a 3-hour interruption of the dark period. Annual species produced significantly more flowers and pegs than perennial species during both long and short days. The total number of flowers produced ranged from 0 during short days for A. correntina to more than 300 for A. cardenasii in long-day treatments. Only one plant of each species A. chacoense and A. villosa, and no plants of A. correntina, flowered in short days. Total numbers of pegs produced in short-day treatments were generally greater than in long-day treatments and the ratio of total number of pegs/total number of flowers was consistently greater during short-day treatments. A general trend was observed for more flowers produced in long-day treatments, but more pegs produced in short days. This study indicated that photoperiod can be manipulated to increase the seed set of some species and the success rate of obtaining certain interspecific hybrids. Furthermore, introgression from wild to cultivated species may possibly alter the reproductive capacity of A. hypogaea to photoperiod.

Short Day Induction of Inflorescence Initiation in Some Winter Wheat Varieties

1987 ◽  
Vol 14 (3) ◽  
pp. 277 ◽  
Author(s):  
LT Evans
Keyword(s):  
Winter Wheat ◽  
High Irradiance ◽  
Inflorescence Development ◽  
Wheat Varieties ◽  
Short Day ◽  
Long Day ◽  
European Winter Wheat ◽  
Lower Irradiance ◽  
Short Days ◽  
Winter Wheat Varieties

Experiments in the Canberra phytotron with several European winter wheat varieties, especially cv. Templar, have shown that their need for vernalisation at low temperature can be replaced entirely by growth in short days at 21/16°C for the same period. In fact, although wheat is usually classified as a long day plant, inflorescence initiation at 21/16°C in unvernalised plants was twice as rapid in 8 h photoperiods as in 16 h ones. Short day induction was fastest in photoperiods of less than 12 h and was relatively insensitive to irradiance. Inflorescence development following initiation was faster the longer the photoperiod. At high irradiance, anthesis eventually occurred in 8 h days, but not at lower irradiance. These wheats are therefore short-long day plants, and may appear to be indifferent to daylength if only their time to anthesis is observed. Although short days can replace low temperatures, there are several important differences in their modes of action, and short day induction is better not referred to as short day vernalisation. Vernalisation of developing grains in the ear was more effective in long days.

Gonadal and photoperiodic control of seasonal body weight changes in male voles

1984 ◽  
Vol 247 (1) ◽  
pp. R84-R88 ◽  
Author(s):  
J. Dark ◽  
I. Zucker
Keyword(s):  
Body Weight ◽  
Body Mass ◽  
Late Summer ◽  
Short Photoperiod ◽  
Late Winter ◽  
Weight Changes ◽  
Short Day ◽  
Long Day ◽  
Principal Factors ◽  
Gonadal Recrudescence

After 15 wk in a short photoperiod (10 h of light/day), adult male voles weighed 25% less and consumed 33% less food than did voles in a long photoperiod (14 h light/day). Neither body weight nor food intake differed among long- and short-day castrated voles. After 19 wk, castrated long-day voles weighed less than did intact animals. Voles reduced their body weight during the first 15 wk in the short photoperiod and increased their body mass during the succeeding 15 wk. Body mass of short-day voles was positively correlated with combined testes weight. Voles in the short photoperiod collected less nesting material than did their long-day counterparts at week 31. Pelage characteristics at week 32 were not affected by castration or by photoperiod. We conclude that the decreased body mass of male voles during the late summer, fall, and early winter reflects a decrease in circulating levels of testicular hormones; gonadal recrudescence and increased circulating androgen levels are in part responsible for the subsequent seasonal increase in body weight. Part of the increased body mass in late winter in field populations or in laboratory voles after 15 wk in the short photoperiod is independent of the resumption of gonadal activity. Fluctuations in neural and endocrine processes, rather than availability of food, are the principal factors underlying seasonal changes in energy balance.

scholarly journals Inflorescence Initiation in Lolium Temulentum l. II. Evidence for Inhibitory and Promotive Photoperiodic Processes Involving Transmissible Products

1960 ◽  
Vol 13 (4) ◽  
pp. 429 ◽  
Author(s):  
LT Evans
Keyword(s):  
Leaf Blade ◽  
Light Period ◽  
Continuous Illumination ◽  
Rate Of Development ◽  
Lolium Temulentum ◽  
Short Day ◽  
Long Day ◽  
Inductive Treatment ◽  
Short Days

Plants of Lolium temulentum, raised in short days, were given an inductive treatment by exposure of one leaf blade to a 32-hr period of continuous illumination. Then either the leaf exposed to this one long light period or varying areas of lower leaves which were simultaneously in short-day conditions were removed at intervals after the long-day exposure. The longer the long-day leaves remained on the plants, the greater was the proportion of plants which initiated inflorescences and the greater the rate of development of their inflorescences. This was so even when short-day leaves were present above the long-day ones. The longer the short-day leaves remained, and the greater their area, the lower was the proportion of plants which initiated inflorescences.

Leaf development in two-row spring barley under long-day and short-day field conditions

2004 ◽  
Vol 84 (2) ◽  
pp. 477-486 ◽  
Author(s):  
B. H. Paynter ◽  
P. E. Juskiw ◽  
J. H. Helm
Keyword(s):  
Hordeum Vulgare ◽  
Western Australia ◽  
Spring Barley ◽  
Linear Regression Analysis ◽  
Leaf Number ◽  
Hordeum Vulgare L ◽  
Short Day ◽  
Leaf Emergence ◽  
Long Day ◽  
Short Days

To gain an understanding of the adaptation of Australian and Canadian barley (Hordeum vulgare L.) cultivars to the environments of western Canada and Western Australia, phyllochron and number of leaves on the mainstem in eight cultivars of two-row, spring barley were examined when sown at two dates in two locations. The locations were a short-day environment at Northam, Western Australia, Australia in 1997 and a long-day environment at Lacombe, Alberta, Canada in 1998. At each location highly significant relationships between leaf number on the mainstem and thermal time were found (r2 > 0.94). Using linear estimates, the phyllochron of barley under short days was longer than under long days and was correlated to time to awn emergence. Later sowing shortened phyllochron under short days, but generally not under long days. Error messages from the linear regression analysis suggested that residuals were not random for all cultivars. Bilinear models were fitted to those datasets. Bilineal responses were observed under both short and long days, being independent of cultivar, date of seeding, final leaf number, phenological development pattern and time to awn emergence. The occurrence of a bilinear response was also independent of any ontogenetic events. The change in phyllochron occurred between leaves 4–7 at Northam and between leaves 6–9 at Lacombe. The leaf number at which the phyllochron change occurred was positively related to final leaf number and time to awn emergence. The phyllochron of early forming leaves was positively related to time to awn emergence and shorter than later forming leaves. Leaf emergence patterns in spring barley under both long-day and short-day conditions may therefore be linear or bilinear. Key words: barley (spring), Hordeum vulgare L., phyllochron, leaf emergence, daylength

scholarly journals Effect of High Intensity Interval and Continuous Swimming Training on Body Mass Adiposity Level and Serum Parameters in High-Fat Diet Fed Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Guilherme L. da Rocha ◽  
Alex H. Crisp ◽  
Maria R. M. de Oliveira ◽  
Carlos A. da Silva ◽  
Jadson O. Silva ◽  
...  
Keyword(s):  
Body Mass ◽  
High Fat Diet ◽  
Interval Training ◽  
Mass Gain ◽  
The Body ◽  
Standard Diet ◽  
High Fat ◽  
Continuous Training ◽  
Body Mass Gain ◽  
Training Standard

This study aimed to investigate the effects of interval and continuous training on the body mass gain and adiposity levels of rats fed a high-fat diet. Forty-eight male Sprague-Dawley rats were randomly divided into two groups, standard diet and high-fat diet, and received their respective diets for a period of four weeks without exercise stimuli. After this period, the animals were randomly divided into six groups (n=8): control standard diet (CS), control high-fat diet (CH), continuous training standard diet (CTS), continuous training high-fat diet (CTH), interval training standard diet (ITS), and interval training high-fat diet (ITH). The interval and continuous training consisted of a swimming exercise performed over eight weeks. CH rats had greater body mass gain, sum of adipose tissues mass, and lower serum high density lipoprotein values than CS. The trained groups showed lower values of feed intake, caloric intake, body mass gain, and adiposity levels compared with the CH group. No significant differences were observed between the trained groups (CTS versus ITS and CTH versus ITH) on body mass gains and adiposity levels. In conclusion, both training methodologies were shown to be effective in controlling body mass gain and adiposity levels in high-fat diet fed rats.

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