Relationship between endogenous opioids and the oestrous cycle in the rat

G. K. Hulse, G. J. Coleman, D. L. Copolov, J. A. Clements

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The aim of this study was twofold: (1) to document changes in levels of immunoreactive β-endorphin (Ir-β-EP) in the hypothalamus, anterior pituitary gland, neurointermediate lobe and plasma during the oestrous cycle of the rat and (2) to investigate stress-induced changes in plasma Ir-β-EP at different stages of the oestrous cycle. Evidence was found that Ir-β-EP levels in the hypothalamus, anterior pituitary gland and plasma are not constant during the oestrous cycle and that the Ir-β-EP response to stress is a function of the phase of the oestrous cycle at which stress is applied. It is suggested that fluctuations in ovarian hormones may influence oestrous Ir-β-EP levels both under normal conditions and after exposure to stress.

Original languageEnglish
Pages (from-to)271-275
Number of pages5
JournalJournal of Endocrinology
Issue number3
Publication statusPublished - 1 Jan 1984
Externally publishedYes

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