The effect of spinal cord section on rat liver tryptophan pyrrolase activity

Vaptzarova, K. I.; Davidov, M; Markov, D; Popov, P.G.; Galabov, G

doi:10.1016/0024-3205(69)90152-0

Cited by 7 publications

(1 citation statement)

References 6 publications

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“…A variation of this is obtained on treatment with haem (Badawy & Evans, 1973, 1975) and haem precursor (Wetterberg et al, 1969), but without stabilization of the apoenzyme. The little-known third mode involves the autonomic nervous system in which stimulation of the enzyme activity was obtained on spinal section at C7-8 (Vaptzarova et al, 1969). This may be accounted by a reversal of inhibition of cortisol induction by noradrenaline (Sitaramam & Ramasarma, 1974), identified to function through a-adrenergic receptors (Sitaramam & Ramasarma, 1975b).…”

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confidence: 99%

Stimulation of liver tryptophan pyrrolase during heat exposure

Manjunath¹,

Ramasarma²

1985

Biochemical Journal

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Exposure of rats to heat (39 +/- 1 degree C) stimulated liver tryptophan pyrrolase 2-fold between 3 and 48 h. Plasma corticosterone increased 2-fold after 1 h of heat exposure and decreased to a low value of 50% by 16 h. The effect of heat exposure on the enzyme was obtained in adrenalectomized animals. Stimulation by cortisol and tryptophan of the enzyme was also obtained in heat exposure, and the effects seemed to be additive. The concentration of tryptophan in the liver remained unchanged, and that in the plasma decreased to about 50% at 8 h exposure to heat and reverted to normal by 46 h. Simultaneous administration of noradrenaline to heat-exposed rats had no effect, whereas that of thyroxine partly prevented the stimulation of the enzyme activity. Hypothyroid conditions obtained by thyroidectomy or treatment with propylthiouracil significantly stimulated the enzyme activity. Cycloheximide treatment of heat-exposed rats did not prevent the stimulation of the enzyme activity. The results indicate that the effect of heat exposure on liver tryptophan pyrrolase is obtained, due to the accompanying hypothyroid condition, by increasing the activity of the existing protein by a mechanism possibly different from those known at present.

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confidence: 99%