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.
|Number of pages||10|
|Publication status||Published - Dec 1 1994|
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Endocrine and Autonomic Systems
- Clinical Neurology
- Psychiatry and Mental health