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THE EFFECT OF THYROID DISEASE ON PROINSULIN AND C‐PEPTIDE LEVELS
Author(s) -
BEER S. F.,
PARR J. H.,
TEMPLE R. C.,
HALES C. N.
Publication year - 1989
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1989.tb00435.x
Subject(s) - proinsulin , medicine , endocrinology , c peptide , prohormone , peptide , peptide hormone , chemistry , insulin , hormone , biochemistry
SUMMARY C‐peptide and proinsulin levels were studied in hyper and hypothyroidism both pre and post‐treatment and in comparison to matched normals. Fasting C‐peptide was reduced in untreated hyperthyroidism (0.4 ± 0.2 (mean ± SEM) vs 0.7 ± 0.2 nmol/l, P<0.05) but returned to normal levels following treatment. Fasting proinsulin was elevated in untreated hyperthyroidism (3.6 ± 0.7 vs 2.4 ± 0.5 pmol/l, P <0.05) also returning to normal after treatment. A similar pattern was seen after oral glucose. The increased proinsulin and reduced C‐peptide suggest there may be a defect of proinsulin processing in hyperthyroidism. Fasting C‐peptide was reduced in untreated hypothyroidism (0.4 ± 0.1 vs 0.7 ± 0.1 nmol/l, P <0.05) and also returned to normal after treatment. Fasting proinsulin did not differ significantly from controls. However, proinsulin was reduced after oral glucose (4.7 ± 0.7 vs . 7.9 ± 2.0 pmol/l, P <0.05) as was C‐peptide (0.9 ± 0.2 vs 2.6 ± 0.3 nmol/l, P <0.05). Both returned to normal after treatment. These findings suggest there are abnormalities of proinsulin and C‐peptide levels in both hyper and hypothyroidism.