A subcellular pool of hypo-osmotically resistant particles containing thyrotropin releasing hormone, α-melanocyte stimulating hormone, and luteinizing hormone releasing hormone in the rat hypothalamus

A. Barnea, W. B. Neaves, G. Cho, J. C. Porter

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Abstract

A 10% homogenate of male rat hypothalami, prepared in 0.32 M-sucrose-10 μM-CaCl2, was diluted either with one volume of 0.32 M-sucrose-10 μM-CaCl2 (iso-osmotic) or with 10 μM-CaCl2 (hypo-osmotic). A 900 g supernatant fluid fraction (0.9 K-S) was prepared from the diluted homogenates and fractionated on continuous sucrose density gradients under non-equilibrium and equilibrium conditions. In the iso-osmotic 0.9 K-S thyrotropin releasing hormone (TRH), α-melanocyte stimulating hormone (α-MSH), and luteinizing hormone releasing hormone (LHRH) were each found to be sequestered in two populations of particles which were different in size but similar in density. In the hypo-osmotic 0.9 K-S, TRH, α-MSH, and LHRH were each found to be sequestered in a single population of particles. In their sedimentation properties (as judged by differential, non-equilibrium, and equilibrium density centrifugations), the hypo-osmotically resistant particles and the small particles present in the iso-osmotic 0.9 K-S were identical. However, in their peptide content, the two sets of particles differed from each other. If the total quantity of particle-bound peptides recovered after gradient centrifugation of the iso-osmotic 0.9 K-S is taken as 100%, one finds that the amount of TRH, α-MSH, and LHRH recovered in the small particles is 39%, 50% and 39%, respectively, whereas the amount of TRH, α-MSH, and LHRH recovered in the hypo-osmotically resistant particles is 42%, 68%, and 67% respectively. This increase in the quantity of peptides sequestered in the small particles occurred concomitantly with the disappearance of peptides from the large synaptosome-like particles. It is estimated that within the large synaptosome-like particles 7% of the TRH, 35% of the α-MSH, and 45% of the LHRH are associated with hypo-osmotically resistant particles. Ultrastructural analysis of purified hypo-osmotically resistant particles containing TRH, α-MSH, or LHRH revealed a predominance of membrane-bounded packets of electron-dense material.

Original languageEnglish (US)
Pages (from-to)937-948
Number of pages12
JournalJournal of Neurochemistry
Volume30
Issue number5
StatePublished - 1978

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Melanocyte-Stimulating Hormones
Thyrotropin-Releasing Hormone
Gonadotropin-Releasing Hormone
Hypothalamus
Rats
Sucrose
Peptides
Centrifugation
Synaptosomes
Sedimentation
Population
Electrons
Membranes
Fluids

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

@article{14c51223fc0a48a2b0b6d97f6a3f1e2a,
title = "A subcellular pool of hypo-osmotically resistant particles containing thyrotropin releasing hormone, α-melanocyte stimulating hormone, and luteinizing hormone releasing hormone in the rat hypothalamus",
abstract = "A 10{\%} homogenate of male rat hypothalami, prepared in 0.32 M-sucrose-10 μM-CaCl2, was diluted either with one volume of 0.32 M-sucrose-10 μM-CaCl2 (iso-osmotic) or with 10 μM-CaCl2 (hypo-osmotic). A 900 g supernatant fluid fraction (0.9 K-S) was prepared from the diluted homogenates and fractionated on continuous sucrose density gradients under non-equilibrium and equilibrium conditions. In the iso-osmotic 0.9 K-S thyrotropin releasing hormone (TRH), α-melanocyte stimulating hormone (α-MSH), and luteinizing hormone releasing hormone (LHRH) were each found to be sequestered in two populations of particles which were different in size but similar in density. In the hypo-osmotic 0.9 K-S, TRH, α-MSH, and LHRH were each found to be sequestered in a single population of particles. In their sedimentation properties (as judged by differential, non-equilibrium, and equilibrium density centrifugations), the hypo-osmotically resistant particles and the small particles present in the iso-osmotic 0.9 K-S were identical. However, in their peptide content, the two sets of particles differed from each other. If the total quantity of particle-bound peptides recovered after gradient centrifugation of the iso-osmotic 0.9 K-S is taken as 100{\%}, one finds that the amount of TRH, α-MSH, and LHRH recovered in the small particles is 39{\%}, 50{\%} and 39{\%}, respectively, whereas the amount of TRH, α-MSH, and LHRH recovered in the hypo-osmotically resistant particles is 42{\%}, 68{\%}, and 67{\%} respectively. This increase in the quantity of peptides sequestered in the small particles occurred concomitantly with the disappearance of peptides from the large synaptosome-like particles. It is estimated that within the large synaptosome-like particles 7{\%} of the TRH, 35{\%} of the α-MSH, and 45{\%} of the LHRH are associated with hypo-osmotically resistant particles. Ultrastructural analysis of purified hypo-osmotically resistant particles containing TRH, α-MSH, or LHRH revealed a predominance of membrane-bounded packets of electron-dense material.",
author = "A. Barnea and Neaves, {W. B.} and G. Cho and Porter, {J. C.}",
year = "1978",
language = "English (US)",
volume = "30",
pages = "937--948",
journal = "Journal of Neurochemistry",
issn = "0022-3042",
publisher = "Wiley-Blackwell",
number = "5",

}

TY - JOUR

T1 - A subcellular pool of hypo-osmotically resistant particles containing thyrotropin releasing hormone, α-melanocyte stimulating hormone, and luteinizing hormone releasing hormone in the rat hypothalamus

AU - Barnea, A.

AU - Neaves, W. B.

AU - Cho, G.

AU - Porter, J. C.

PY - 1978

Y1 - 1978

N2 - A 10% homogenate of male rat hypothalami, prepared in 0.32 M-sucrose-10 μM-CaCl2, was diluted either with one volume of 0.32 M-sucrose-10 μM-CaCl2 (iso-osmotic) or with 10 μM-CaCl2 (hypo-osmotic). A 900 g supernatant fluid fraction (0.9 K-S) was prepared from the diluted homogenates and fractionated on continuous sucrose density gradients under non-equilibrium and equilibrium conditions. In the iso-osmotic 0.9 K-S thyrotropin releasing hormone (TRH), α-melanocyte stimulating hormone (α-MSH), and luteinizing hormone releasing hormone (LHRH) were each found to be sequestered in two populations of particles which were different in size but similar in density. In the hypo-osmotic 0.9 K-S, TRH, α-MSH, and LHRH were each found to be sequestered in a single population of particles. In their sedimentation properties (as judged by differential, non-equilibrium, and equilibrium density centrifugations), the hypo-osmotically resistant particles and the small particles present in the iso-osmotic 0.9 K-S were identical. However, in their peptide content, the two sets of particles differed from each other. If the total quantity of particle-bound peptides recovered after gradient centrifugation of the iso-osmotic 0.9 K-S is taken as 100%, one finds that the amount of TRH, α-MSH, and LHRH recovered in the small particles is 39%, 50% and 39%, respectively, whereas the amount of TRH, α-MSH, and LHRH recovered in the hypo-osmotically resistant particles is 42%, 68%, and 67% respectively. This increase in the quantity of peptides sequestered in the small particles occurred concomitantly with the disappearance of peptides from the large synaptosome-like particles. It is estimated that within the large synaptosome-like particles 7% of the TRH, 35% of the α-MSH, and 45% of the LHRH are associated with hypo-osmotically resistant particles. Ultrastructural analysis of purified hypo-osmotically resistant particles containing TRH, α-MSH, or LHRH revealed a predominance of membrane-bounded packets of electron-dense material.

AB - A 10% homogenate of male rat hypothalami, prepared in 0.32 M-sucrose-10 μM-CaCl2, was diluted either with one volume of 0.32 M-sucrose-10 μM-CaCl2 (iso-osmotic) or with 10 μM-CaCl2 (hypo-osmotic). A 900 g supernatant fluid fraction (0.9 K-S) was prepared from the diluted homogenates and fractionated on continuous sucrose density gradients under non-equilibrium and equilibrium conditions. In the iso-osmotic 0.9 K-S thyrotropin releasing hormone (TRH), α-melanocyte stimulating hormone (α-MSH), and luteinizing hormone releasing hormone (LHRH) were each found to be sequestered in two populations of particles which were different in size but similar in density. In the hypo-osmotic 0.9 K-S, TRH, α-MSH, and LHRH were each found to be sequestered in a single population of particles. In their sedimentation properties (as judged by differential, non-equilibrium, and equilibrium density centrifugations), the hypo-osmotically resistant particles and the small particles present in the iso-osmotic 0.9 K-S were identical. However, in their peptide content, the two sets of particles differed from each other. If the total quantity of particle-bound peptides recovered after gradient centrifugation of the iso-osmotic 0.9 K-S is taken as 100%, one finds that the amount of TRH, α-MSH, and LHRH recovered in the small particles is 39%, 50% and 39%, respectively, whereas the amount of TRH, α-MSH, and LHRH recovered in the hypo-osmotically resistant particles is 42%, 68%, and 67% respectively. This increase in the quantity of peptides sequestered in the small particles occurred concomitantly with the disappearance of peptides from the large synaptosome-like particles. It is estimated that within the large synaptosome-like particles 7% of the TRH, 35% of the α-MSH, and 45% of the LHRH are associated with hypo-osmotically resistant particles. Ultrastructural analysis of purified hypo-osmotically resistant particles containing TRH, α-MSH, or LHRH revealed a predominance of membrane-bounded packets of electron-dense material.

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JO - Journal of Neurochemistry

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