Adrenocorticotropic hormone increases hydrolysis of B-6 vitamers in swine adrenal glands
1999
Mahuren, J.D. | Dubeski, P.L. | Cook. N.J. | Schaefer, A.L. | Coburn, S.P.
Shipping stress is an economic problem because of its effect on meat quality. Because shipping increases plasma cortisol and pyridoxal 5'-phosphate interacts with steroid hormones, we examined the interaction between adrenocorticotropic hormone (ACTH) and vitamin B-6 metabolism in pigs. Six crossbred pigs with ear vein catheters received 50 IU of porcine ACTH intravenously at 3-h intervals from 0800 to 2100 h on d 1-3 and 100 IU intramuscularly at 0800, 1400 and 2000 h on d 6 and 7. Controls received saline. ACTH had no effect on pyridoxal 5'-phosphate in adrenal tissue but decreased pyridoxamine 5'-phosphate from 6.1 +/- 0.7 to 4.7 +/- 1.0 nmol/g (P<0.05). Adrenal pyridoxal and pyridoxamine concentrations were 0.4 +/- 1.0 nmol/g in controls and 1.1 +/- 0.3 and 1.3 +/- 0.5 nmol/g, respectively, in ACTH-treated pigs (P<0.01). Pyridoxal 5'-phosphate phosphatase activity [median (25-75 percentile value)] at pH 7.4 in adrenal tissue was 66.6 (47.8-75.5) nmol/(g x min) in the controls and 764 (626-771) in the ACTH-treated pigs (P<0.01). There was no significant difference in pyridoxal kinase activity. However, kinase activity in the adrenals was about twice as high as in other tissues. These data suggest an active turnover of vitamin B-6 in adrenal tissue.
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