摘要:

Liver glycogen, liver lipid, liver triglycerides, plasma glucose, plasma total lipid, plasma cholesterol, plasma corticoids, hypothalamic serotonin and pituitary pro‐lactin levels were assayed at five times over a 24‐h period inCarassius auratusmaintained under a specific photoperiod regime at various times throughout the year. Diurnal variations were observed in all parameters monitored. Daily variations of liver glycogen, plasma glucose, plasma lipid, plasma corticoids and hypothalamic serotonin were affected by time of feeding. Liver glycogen, plasma lipid and plasma corticoid levels were also affected by time of feeding. Diurnal variations of liver glycogen, plasma glucose and plasma lipid were influenced by light‐dark cycles. These data illustrate that feeding time, photoperiod and time of sacrifice are important considerations in the study of metabolic and hormonal parameters in fishes.

ISSN:0022-1945    

DOI:10.1080/09291017809359626

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Endogenous ACTH and cortisol was suppressed in horses with dexamethasone. Exogenous ACTH‐123I was infused for 3 h at a concentration to produce physiological levels of plasma cortisol. After reaching a plateau concentration of ACTH‐123I, cortisol concentration was constant throughout the remaining infusion period. Ultradian rhythms in cortisol secretion were abolished by the constant concentration of ACTH supporting the concept mat ACTH secretion is the primary regulator of cortisol rhythms. The half‐life of ACTH‐12’I in three horses was 4, 5 and 8 min following cessation of ACTH‐125I infusion.

ISSN:0022-1945    

DOI:10.1080/09291017809359627

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Photoperiodic effect on mitotic activity of buds from dwarfPharbitishas been analyzed. No significant differences in mitotic activity were found in plants grown under long days or diurnal (24 h) light break photoperiodic treatments. Differences in both mitotic activity and flowering were seen in plants subjected to diurnal short days, bidiurnal (48 h) short days, or bidiurnal short days with light breaks. An elevation of mitotic activity occurs in plants grown in bidiurnal photoperiodic treatments compared to diurnal treatments. The differences in mitotic activity of buds, both vegetative and floral, seem to indicate that both phytochrome and light effect on an endogenous rhythm influence meristematic activity. Also, the extended dark period of a bidiurnal short day enhances both mitosis and flowering.

ISSN:0022-1945    

DOI:10.1080/09291017809359628

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Use of intermittent white noise (60 and 70 dB) as an additional synchronizer in the light period (12 h) gave a rise in the level of mitotic index and moved the maximal values 1 to 3 h forward in time. The effects increased with the sound level. Unskilled handling of the animals in itself could produce a significant decrease in mitotic index. Independent of the various external conditions injection of ‘HTdR (1 /μCi/g body weight; 6 Ci/m mol) increased the mitotic index during the first hours after injection.

ISSN:0022-1945    

DOI:10.1080/09291017809359629

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

As part of studies on the interactive effects of light and endocrine factors on hepatic mixed‐function oxidases, the aminopyrine demethylase activity of liver microsomes and the serum concentrations of corticosterone and testosterone were measured in adult male rats (sham‐operated, castrated or adrenalectomized) exposed for 21 days to one of the following types of environmental lighting: (1) Normal light cyle (L from 09.00 to 21.00 h); (2) Reverse light cycle; (3) Constant light (LL) or (4) Constant darkness (DD). One half of the animals in each of the 12 groups was killed at 06.00 h and the other at 18.00 h on the last day of treatment. A 3‐way analysis of variance, multiple comparisons and correlations allowed the following conclusions: (1) The type of lighting had the most significant effect on demethylase activity, its highest values correspondingtoperiods of darkness (particularly in the rats exposed to a reverse light cycle) and its lowest to LL. (2) Castrated rats as a group had the lowest demethylase activity. (3) Time of death was a significant factor, particularly for the rats in a reverse light cycle (higher activity at 18.00 than at 06.00 h). (4) There was a significant and positive correlation between aminopyrine demethylase and the rates of 7α‐hydroxylation of 3β‐hydroxy‐5‐androsten‐17‐one previously reported for the same animals. (5) There was no significant correlation between demethylase activity and serum corticosterone or testosterone.

ISSN:0022-1945    

DOI:10.1080/09291017809359630

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Intact and hypophysectomized goldfish(Carassius auratusL.) were given intra‐coelomic injections of ovine prolactin at cither 09.00 h or 16.00 h (2 h and 9 h after the onset of the photoperiod, respectively). The effects of prolactin on plasma Na+, K+, Cl‐and osmotic pressure, total body water content, liver lipid content, total body lipid content and liver glycerol‐3‐phosphate acyltransferase activity were determined in an attempt to detect circadian variability in the response to exogenous prolactin.

ISSN:0022-1945    

DOI:10.1080/09291017809359631

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Locomotor activity in hamsters,Mesocricetus auratus.in 24‐h LD cycles with light from 06.00 to 18.00 h, and simultaneously in imposed 26‐h weak magnetic cycles (ranges varying from 0.260 to 0.008 gauss), significantly reflected both periods. A 24‐h circadian pattern (ca. 200% of mean) was modulated by a concurrent 26‐h circadian pattern (range ca. 14% of mean).

ISSN:0022-1945    

DOI:10.1080/09291017809359632

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291017809359625

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor