Dehydration decreases plasma level of α-melanocyte stimulating hormone (α-MSH) and attenuates suckling-induced β-endorphin but not ACTH response in lactating rats

G. M. Nagy, M. Vecsernyes, J. Julesz, I. Barna, J. I. Koenig

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When lactating rats are exposed to a short term dehydration, anterior lobe (AL) prolactin (PRL) secretion is immediately depressed. Since tuberohypophysial dopaminergic (THDA) neurons are osmosensitive and regulate the secretion of POMC peptides (α-MSH and β-endorphin) form the intermediate lobe (IL) and dopamine is known to be the major physiological regulator of PRL secretion we have investigated the effect of dehydration on plasma levels of α-MSH, ACTH and β-endorphin detected after suckling stimulus in lactating rats. Changes in the hydromineral balance induced by salt loading severely attenuated plasma level of α-MSH. This effect seems to be specific on peptides secreted by melanotropes because neither basal nor suckling-induced ACTH secreted by corticotropes changed during dehydration. Reduction in plasma level of β-endorphin due to 4 h separation was intensified and the suckling-induced response was attenuated in dehydrated mothers. In summary, the simultaneous and resembling changes in the release of α-MSH, β-endorphin and PRL support our assumption that the regulation of AL and IL is closely coupled and THDA system is one of the common hypothalamic pathways.

Original languageEnglish
Pages (from-to)275-284
Number of pages10
JournalNeuroendocrinology Letters
Issue number5-6
Publication statusPublished - Dec 1 1994


ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Neurology
  • Endocrine and Autonomic Systems
  • Clinical Neurology
  • Psychiatry and Mental health

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