Adrenocorticotropin, beta-endorphin, and beta-lipotropin in normal thyroid and lung: possible implications for ectopic hormone secretion.

Abstract:

:The expression of the proopiomelanocortin (POMC) gene by normal lung and thyroid was examined by measurement of the content of ACTH, beta-lipotropin (beta LPH), and beta-endorphin (beta EP) in porcine lung and thyroid tissue. Acid extracts of normal porcine lung and thyroid tissue each contained appreciable amounts of immunoreactive (ir) ACTH, ir-beta LPH, and ir-beta EP. The content of ir-beta LPH in both tissues exceeded by severalfold, on a molar basis, the content of ir-ACTH and ir-beta EP, suggesting that the common precursor POMC was processed predominantly to peptides other than ir-ACTH and ir-beta EP. A porcine thyroid extract (Calcitare, porcine calcitonin, Armour) showed equivalent levels of beta EP-like immunoreactivity and bioactivity, measured by opiate radioreceptor assay; in contrast, ACTH-like bioactivity, measured by rat zona fasciculata steroidogenesis, was only 4% of ACTH-like immunoreactivity. On reversed phase high performance liquid chromatography, Calcitare showed multiple peaks of ACTH-like immunoreactivity, one of which coeluted with porcine ACTH-(1-39), and two much smaller peaks of beta EP-like immunoreactivity, of which the smaller coeluted with porcine beta EP. These data suggest that both lung and thyroid gland synthesize POMC, which in normal tissue is usually predominantly processed to species other than ACTH and beta EP. Ectopic secretion of ACTH and beta EP by lung and thyroid neoplasms may thus represent the loss of a system(s) normally responsible for processing the precursor beyond ACTH and beta EP.

journal_name

Endocrinology

journal_title

Endocrinology

authors

Clements JA,Funder JW,Tracy K,Morgan FJ,Campbell DJ,Lewis P,Hearn MT

doi

10.1210/endo-111-6-2097

subject

Has Abstract

pub_date

1982-12-01 00:00:00

pages

2097-102

issue

6

eissn

0013-7227

issn

1945-7170

journal_volume

111

pub_type

杂志文章