Abstract
Immunocytochemistry, radioimmunoassay and high-performance liquid chromatography (HPLC) techniques have been used in combination to investigate the presence of immunoreactive (ir)-alpha-MSH in the normal human pituitary gland, and to investigate the possible origin of these cells from the fetal pars intermedia. Two separate antisera to alpha-MSH were employed in immunocytochemistry to distinguish between authentic alpha-MSH and the desacetyl form. Only desacetyl alpha-MSH was detected in the pituitary gland of fetal and adult man, in both the pars (zona) intermedia and the pars anterior. In the fetus, a large proportion of the ACTH-containing cells of the anterior lobe also contained ir-alpha-MSH, while ir-alpha-MSH containing cells were more sparse in adults. Radioimmunoassay of acid extracts of adult pituitary tissue showed alpha-MSH levels representing less than 0.05% of the ACTH content of the gland. HPLC analysis of these extracts confirmed that only the desacetyl form was present. These results suggest that alpha-MSH peptides are synthesized by anterior lobe cells of the human pituitary gland, which are not derived from the fetal pars intermedia. Possible regulatory mechanisms affecting cells which contain ir-alpha-MSH are discussed, and by comparison with the intermediate lobe of other species it is concluded that there is little evidence for a true intermediate lobe in the human pituitary gland.
| Original language | English |
|---|---|
| Pages (from-to) | 525-530 |
| Number of pages | 6 |
| Journal | Journal of Endocrinology |
| Volume | 120 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 1989 |