Cyclic changes in the glycogen content of the liver and the muscles of rats and mice

Ågren, Gunnar; Wilander, Olof; Jorpes, Erik

doi:10.1042/bj0250777

Cited by 102 publications

(16 citation statements)

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“…An awareness of the influence of the time of day at which an experiment is conducted upon its ultimate outcome is increasing (Agren, Wilander & Jorpes, 1931;Scheving & Pauly, 1966;Mills, 1966;Krieger & Krieger, 1967;von Mayersbach, 1967). Any attempt to quantify biological data must be made with the realization that variations occur during the course of a day and that such changes vary from a few per cent to several fold.…”

Section: Introductionmentioning

confidence: 99%

Circadian rhythms in rat mid‐brain and caudate nucleus biogenic amine levels

Friedman¹,

Walker²

1968

The Journal of Physiology

156

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SUMMARY1. The circadian rhythms of rectal temperature and biogenic amine levels in mid-brain and caudate nucleus have been measured in normal and adrenalectomized rats adapted to and maintained under fixed illumination cycle.2. Rectal temperature reaches a peak value between 24.00 hr and 06.00 hr during the dark phase of the illumination cycle at a time when motor activity is maximal. In adrenalectomized rats, the pattern is similar but the peak is significantly lower.3. Highest histamine levels in the caudate nucleus and mid-brain of normal and adrenalectomized rats are found at the time when body temperature and motor activity is maximal.4. Similarly, caudate nucleus and mid-brain noradrenaline levels reach their peak during the dark phase of the illumination cycle. These levels are significantly different from those found during the light phase of the illumination cycle. The rise in noradrenaline in the mid-brain of adrenalectomized rats, however, was not significant.5. Peak 5-hydroxytryptamine (5-HT) levels in the caudate nucleus of normal rats and the mid-brain of adrenalectomized rats were found to be 12 hr out of phase with peak values obtained for other parameters that were measured.6. The significance ofthese circadian rhythms in relation to states of sleep and wakefulness, general metabolism, and motor activity is discussed.

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Section: Introductionmentioning

confidence: 99%

Circadian rhythms in rat mid‐brain and caudate nucleus biogenic amine levels

Friedman¹,

Walker²

1968

The Journal of Physiology

156

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“…Removal of the adrenal gland abolishes eosinophil rhythm and glycogen rhythm in the liver, according to Agren.l.5. 13 The central nervous system has no effect on adrenal rhythm, as Halberg noted that the cycle is found in brainless animals.…”

Section: • 15mentioning

confidence: 97%

“…18 Extirpation of the adrenal gland, however, abolishes the glycogen rhythm in the liver. 13 The well-known seasonal rhythms occurring in pathologic states cause a seasonal mortality rhythm. Many infectious diseases have seasonal peaks.…”

Section: • 15mentioning

confidence: 99%

Circadian Rhythms

Mitchell

1968

Postgraduate Medicine

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“…THE preparation of crystalline secretin has already been described [Hammarsten et al 1928;Agren & Wilander, 1932;Hammarsten et al 1933a, b] and a full description of its properties has been given [Agren, 1934, 1935a, b, Agren et al 1936a, b, c, 1937a. The secretin used for the experiments described in the present paperwas the chloride or phosphateprepared from crystalline secretin.…”

Section: Institutet Stockholm (Received 3 April 1937)mentioning

confidence: 99%

“…The CRYSTALLIZED SECRETIN determinations were carried out by the micro-methods of LinderstromLang [1931]. The standardizations of the digested secretin were made on cats by our own method [Agren & Wilander, 1932] Carefully made standardizations on cats showed that the activity was absolutely unaffected by digestion in this, as in all similar experiments. 4*1 c.mm.…”

Section: Institutet Stockholm (Received 3 April 1937)mentioning

confidence: 99%

The behaviour of crystallized secretin when digested with proteolytic enzymes

Ågren¹,

Hammarsten²

1937

The Journal of Physiology

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THE preparation of crystalline secretin has already been described [Hammarsten et al. 1928;Agren & Wilander, 1932; Hammarsten et al. 1933a, b] and a full description of its properties has been given [Agren, 1934, 1935 a, b, Agren et al. 1936 a, b, c, 1937a. The secretin used for the experiments described in the present paperwas the chloride or phosphateprepared from crystalline secretin. These salts were amorphous.An analytical digestion of secretin with aminopolypeptidase and with carboxypolypeptidase seemed to us to be of special interest on account of the ninhydrin reaction with secretin before and after hydrolysis, its isoelectric point, and the fact that one amino-group can be split off by van Slyke determination without loss of activity. Secretin is a basic polypeptide, which does not give the ninhydrin reaction. It can be hydrolysed with pepsin or trypsin, and at higher temperatures in alkaline or acid solution. In consequence it is inactivated and now gives a strong ninhydrin reaction. As far as we know, this combination is unique, and we have compared the ninhydrin reaction of amino-acids with that of secretin in a series of concentrations, secretin not giving the slightest trace of colour, even in very high concentrations and after evaporation to dryness. The reaction is very sensitive to the hydrogen-ion concentration and pH 6-8 is the optimum for development of colour. This was therefore used. After, the determination of the isoelectric point, it was clear that secretin was an amphoteric substance and by means of digestion with carboxypolypeptidase we hoped to determine the nature of the acid group. Aminopolypeptidase was prepared according to Agren [1937]. The preparation was made from hog's gastric mucosa in order that a trypsin-free glycerine solution might be obtained. The

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Cyclic changes in the glycogen content of the liver and the muscles of rats and mice

Cited by 102 publications

References 1 publication

Circadian rhythms in rat mid‐brain and caudate nucleus biogenic amine levels

Circadian rhythms in rat mid‐brain and caudate nucleus biogenic amine levels

Circadian Rhythms

The behaviour of crystallized secretin when digested with proteolytic enzymes

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