A study of corticotrophic and melanotrophic activities in the pituitary and brain of the lamprey Lampetra fluviatilis.
Biological and radioimmunological assay methods were used in an attempt to detect and determine corticotrophic and melanotrophic activity in the pituitary gland and the central nervous system of the lamprey, Lampetra fluviatilis. The activities of various corticotrophin (1-39 ACTH)-related peptides in the cytochemical assay for ACTH could be readily distinguished on the basis of their dose-response lines. Extracts of the pituitary gland and brain but not of spinal cord were also active in this test. The dose-response lines of the pars distalis extracts were parallel with those of 1-39 ACTH; those of the neurointermediate lobe and the brain resembled des-Ac-alpha-MSH and alpha-MSH, respectively, although subsequent tests showed that the active molecules in the extracts differed from these standard peptides in other respects. Pituitary extracts were active in the Anolis bioassay for melanotrophin but not in a radioimmunoassay for alpha-MSH. Moreover, the electrophoretic Rf value of lamprey melanotrophic activity was distinct from both alpha-MSH and des-Ac-alpha-MSH. Brain extracts showed only low melanotrophic bioactivity and again no immunoreactivity. The results suggest that small amounts of corticotrophin occur in the pars distalis of the lamprey and that the melanotrophic factors in the neurointermediate lobe and brain are not identical to mammalian alpha-MSH and des-Ac-alpha-MSH.
D000324:Adrenocorticotropic Hormone / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D001681:Biological Assay; D001921:Brain / Q000378:metabolism*; D005399:Fishes / Q000378:metabolism*; D006651:Histocytochemistry; D007798:Lampreys / Q000378:metabolism*; D009074:Melanocyte-Stimulating Hormones / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism*; D010902:Pituitary Gland / Q000378:metabolism*; D011863:Radioimmunoassay
D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones