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VIP enhances TRH‐stimulated prolactin secretion of pituitary tumours
Author(s) -
Prysor-Jones R.A.,
Silverlight J.J.,
Jenkins J.S.,
Stevens A.N.,
Rodrigues J.L.,
Griffiths J.R.
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)80983-7
Subject(s) - medicine , vasoactive intestinal peptide , endocrinology , prolactin , thyrotropin releasing hormone , secretion , chemistry , hormone , metabolite , intracellular , pituitary gland , basal (medicine) , biology , neuropeptide , biochemistry , receptor , insulin
Intravenous thyrotrophin releasing hormone (TRH) caused a 6.5‐fold increase in plasma prolactin (PRL) in rats carrying implanted pituitary tumours. Vasoactive intestinal polypeptide (VIP) had no effect, but TRH given after VIP raised TRH stimulated secretion 13‐fold above basal. 31 P NMR spectroscopy showed that VIP caused a decrease in high energy metabolites (depleted phosphocreatine, elevated inorganic phosphate and lowered intracellular pH). TRH alone caused a similar but smaller effect; given after VIP, it caused no detectable depletion. We suggest that the changes in high energy metabolite cencentrations reflect increased cellular energy consumption consistent with a priming process (stage 1) in PRL secretion, followed by hormone release (stage 2). VIP induces stage 1 whereas RTH induced both stages.