The distribution of melanin-concentrating hormone-like immunoreactivity in the central nervous system of rat, guinea-pig, pig and man.
The distribution of melanin-concentrating hormone-like immunoreactivity was investigated by radioimmunoassay in the CNS of rat, guinea-pig, pig and man. Highest concentrations of melanin-concentrating hormone-like immunoreactivity were found in the hypothalamus of all the species: rat 204.4 +/- 14.9; guinea-pig 159.5 +/- 23.3; pig 10.9 +/- 4.5 and man 80.1 +/- 19.1 pmol/g. Gel chromatographic analysis of hypothalamic extracts showed five immunoreactive peaks of melanin-concentrating hormone-like immunoreactivity in the rat and pig and six in the guinea-pig and man. High-performance liquid chromatography analysis of hypothalamic extracts showed five immunoreactive peaks in rat, guinea-pig, pig and four in man. However, these peaks appeared at different retention times from that of the single peak of salmon melanin-concentrating hormone. Examination of subcellular fractions of whole rat brain showed that most of the melanin-concentrating hormone-like immunoreactivity is found in the synaptosome fraction. Stimulation of melanin-concentrating hormone-like immunoreactivity release from rat hypothalamic slices revealed that potassium in the presence of calcium stimulated melanin-concentrating hormone-like immunoreactivity release. These findings suggest that mammalian melanin-concentrating hormone-like immunoreactivity has a different amino acid sequence from salmon melanin-concentrating hormone and may exist in multiple molecular forms. It is possible that melanin-concentrating hormone may play a role as a neurotransmitter or modulator in the mammalian CNS.
Sekiya
K
K
Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, U.K.
Ghatei
M A
MA
Lacoumenta
S
S
Burnet
P W
PW
Zamir
N
N
Burrin
J M
JM
Polak
J M
JM
Bloom
S R
SR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001921:Brain / Q000378:metabolism*; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D007028:Hypothalamic Hormones; D008297:Male; D008543:Melanins / Q000378:metabolism*; D008875:Middle Aged; D010907:Pituitary Hormones / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; C019463:melanin-concentrating hormone