摘要:

Previously, the authors have reported seasonal variations in cell mediated immunity in the dog during the period July, 1977 ‐ October 1978 as measured by whole blood lectin‐induced lymphocyte transformation. Peak activity occurred in the summer, suggesting association with photoperiodicity. Here the authors report on immune response of dogs kept indoors ‐ under controlled physical environment ‐ with a natural (outdoor) photoperiod or under a 12:12 h (LD) regime, and a control group kept in outdoor kennels. Peak immune activity in 1979 occurred in the winter, in both indoor groups as well as the outdoor groups subject to natural photoperiod. Since the indoor dogs were kept at a constant temperature and humidity in clean (filtered) air, photoperiod, temperature, and particulate air contaminants probably are not associated with seasonal variations in immunity. The underlying cause for either the seasonal variations or the shift from peak activity in the summer of 1978 to winter of 1979 is unknown. Dogs under LD = 12:12 light regime had a significantly lowered immunity relative to the dogs with the natural photoperiod.

ISSN:0022-1945    

DOI:10.1080/09291018209359777

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Diurnal leaf movements inOxalis acetosellaandOxalis regnelliishow no sinusoidal shape. The movements are clipped by physiological limits revealing a curve similar to a square wave. Regarding this circumstances the following results have been obtained from long‐term recordings:1.Concerning the recorded shape of the movement it seems unjustified to discriminate only between two states as “day position” and “night‐position” of the leaflets as done until now, since this would neglect the transitions between these positions as the events of real movement. These transitions vary with season.2.The seasonal differences in the circadian pattern of leaf movements, previously described by Mu'ller‐Haeckel are caused by the different steepness of the transitions; the latter depend upon factors of the ZG as LD‐ratio or the magnitude of light‐intensity steps.3.The speeds of spreading movement and folding movement depend to different extents (without interdependence) upon the schedule of a natural artificial LD‐cycle.4.Since the steepness of a transition (i.e. duration or violence of a movement) resembles the magnitude of a driving amplitude, the findings of ZG‐dependence of this amplitude and the mutual independence of spreading and folding speed suggest the existence of two separate systems that attain their driving amplitudes by resonance to the exciting influence of the ZG.5.It can be demonstrated statistically that the phase‐angle differences and the duration of a transition between “day position” and “night‐position” (or vice versa) reveal linear correlations. This resembles fixed phase relations between the ZG and the entrained resonance oscillation that are independent of the seasonal changes of the LD‐schedule.

ISSN:0022-1945    

DOI:10.1080/09291018209359778

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The hormonal control of rhythmic fluctuations in hepatic microsomal mixed function oxidase activity was examined by incubating microsomes prepared from intact control, sham‐operated, pinealectomized (PX), adrenalectomized (AX), and pinealectomized‐adrenalectomized (PXAX) adult male rats with aminopyrine (AP) and [4‐C14]3ß‐hydroxy‐5‐androsten‐17‐one (DHA). The animals were kept on a 12:12 light‐dark cycle for 15 days prior to killingatl, 4, 6 and 10 hafter light and at 1, 4, 6 and 10 h after dark. The rate of both theN‐demethylation of AP and the 7α‐hydroxy lation of DHA varies diurnally with maximal and minimal activities in the dark and light periods, respectively. The fluctuation in both reactions fits a symmetric sine curve for all endocrine treatment groups except for the 7α‐hydroxylation in PX animals. PXAX was the only treatment resulting in a significant increase in 7α‐hydroxylase activity. The data suggest that the pineal may be involved in mediating the effects of environmental light on liver 7α‐hydroxylase activity.

ISSN:0022-1945    

DOI:10.1080/09291018209359779

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Rainbow trout(Salmo gairdneri)were adapted to long (LD = 12:12) or short (LD = 8:16) daily photoperiods and pituitary, plasma and tissues were collected from fish sampled over a 24 h period to examine possible diurnal variation in pituitary somatotrop activity, plasma free fatty acid (FFA) concentration and liver, muscle and carcass lipid content. Trout acclimated to both long and short daily photoperiods showed a similar significant daily cycle of somatotrop activity with peak activity occurring during the second half of the dark phase. Plasma FFA levels in trout on a long photoperiod similarly showed a significant diurnal variation and there was a significantdirectcorrelation between somatotrop activity and plasma FFA concentration, whereas in trout acclimated to a short daily photoperiod plasma FFA levels did not vary diurnally and there was a significantinversecorrelation between somatotrop activity and plasma FFA levels. There were no consistent diurnal changes in liver, muscle or carcas lipid content with the possible exception of an increase in muscle lipid content in the second half of the dark period in trout acclimated to the short daily photoperiod.

ISSN:0022-1945    

DOI:10.1080/09291018209359780

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Female goldfish were acclimated to an 8 h light photoperiod and 14–15°C, and, in separate experiments, injected daily for 18 and 14 days with low doses of a partially purified salmon gonadotropin (sGtH) or a highly purified carp gonadotropin (cGtH), respectively at either the onset of light, or 4 or 8 h after the onset of light. The response to GtH injection was measured by the gonadosomatic index (GSI) and by histoiogical analyses of oocy te development. There was a response to sGtH injected at 8 h and to cGtH at 4 h and 8 h after the onset of light. Female goldfish acclimated to a 16 h light photoperiodand injected with low doses of cGtH at either the onset of light or at 4, 8, 12 or 16 h after the onset of light for 14 days had an increased GSI in response to the cGtH injected at 12 h after the onset of light. These results demonstrate that there is a daily variation in responsiveness of the ovary of goldfish to GtH.

ISSN:0022-1945    

DOI:10.1080/09291018209359781

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The circadian levels of serotonin (5‐HT) in the cerebral cortex and midbrain of adult male mice adapted to an LD 12:12 cycle were determined in control animals and in animals treated with 10 mg/kg intraperitoneally of amphetamine sulfate at 03.00 h, 07.00 h, 15.00 h or 19.00 h.

ISSN:0022-1945    

DOI:10.1080/09291018209359782

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018209359776

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor