TY - JOUR
T1 - SUBCELLULAR LOCALIZATION OF α‐MELANOCYTE‐STIMULATING HORMONE IN THE RAT HYPOTHALAMUS
AU - Barnea, A.
AU - Oliver, C.
AU - Porter, J. C.
PY - 1977/10
Y1 - 1977/10
N2 - Homogenates of male rat hypothalami were fractionated by means of differential centrifugation, and α‐melanocyte‐stimulating hormone (α‐MSH) in the various fractions was quantified by radioimmunoassay. Of the total quantity of α‐MSH in the homogenate, 36% was recovered in the 11,500 g pellet and 31% sedimented between 11,500 and 105,000 g. α‐MSH was not detected in the 105,000 g supernatant fluid. When the 900 g supernatant fluid was fractionated on continuous sucrose density gradients at non‐equilibrium conditions, two populations of particles containing α‐MSH were observed. When fractionated at equilibrium conditions, the two populations were recovered in a single band. These sedimentation characteristics indicate that the particles that contain α‐MSH differ in size but are similar in density. After hypo‐osmotic shock, the large particles containing α‐MSH were not demonstrable, whereas the small particles appeared to be resistant to such treatment. In their sedimentation, the particles containing α‐MSH were indistinguishable from particles containing thyrotropin releasing hormone (TRH) but were separable from those that contained luteinizing hormone releasing hormone (LHRH). It is suggested that the large particles containing α‐MSH are synaptosomes.
AB - Homogenates of male rat hypothalami were fractionated by means of differential centrifugation, and α‐melanocyte‐stimulating hormone (α‐MSH) in the various fractions was quantified by radioimmunoassay. Of the total quantity of α‐MSH in the homogenate, 36% was recovered in the 11,500 g pellet and 31% sedimented between 11,500 and 105,000 g. α‐MSH was not detected in the 105,000 g supernatant fluid. When the 900 g supernatant fluid was fractionated on continuous sucrose density gradients at non‐equilibrium conditions, two populations of particles containing α‐MSH were observed. When fractionated at equilibrium conditions, the two populations were recovered in a single band. These sedimentation characteristics indicate that the particles that contain α‐MSH differ in size but are similar in density. After hypo‐osmotic shock, the large particles containing α‐MSH were not demonstrable, whereas the small particles appeared to be resistant to such treatment. In their sedimentation, the particles containing α‐MSH were indistinguishable from particles containing thyrotropin releasing hormone (TRH) but were separable from those that contained luteinizing hormone releasing hormone (LHRH). It is suggested that the large particles containing α‐MSH are synaptosomes.
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U2 - 10.1111/j.1471-4159.1977.tb07777.x
DO - 10.1111/j.1471-4159.1977.tb07777.x
M3 - Article
C2 - 412919
AN - SCOPUS:0017726699
SN - 0022-3042
VL - 29
SP - 619
EP - 624
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
IS - 4
ER -