title: Differential response of neuropeptide Y, substance P and vasoactive intestinal polypeptide in the rat anterior pituitary gland to alterations in thyroid hormone status.
abstract: We have compared the effects of thyroidectomy with those of thyroxine (T4) replacement and excess T4 treatment on neuropeptide Y (NPY) in the rat anterior pituitary, and compared these with the effects on substance P (SP) and vasoactive intestinal peptide (VIP). Thyroidectomy produced large increases in the peptide content of NPY (335 +/- 58 fmol/gland vs 15 +/- 4 fmol/gland in controls), SP (581 +/- 90 vs 199 +/- 32 fmol/gland) and VIP (1386 +/- 395 vs 417 +/- 77 fmol/gland) together with large increases in the respective prohormone encoding mRNAs, NPY 21,760% +/- 1290%, preprotachykinin-A (PPT-A; which encodes the substance P precursor) 1744% +/- 190% and VIP 680% +/- 129%. Thyroidectomy together with T4 replacement produced an increase in both NPY peptide (426 +/- 72 vs 15 +/- 4 fmol/gland) and mRNA content (970% +/- 156% of controls). The peptide contents of SP and VIP were not significantly different from controls. PPT-A and VIP mRNA levels were decreased relative to controls (31% +/- 8% and 23% +/- 10% respectively). In intact animals treated with excess T4 (hyperthyroid animals), SP and VIP peptide contents were significantly reduced (55 +/- 13 vs 199 +/- 32 fmol/gland and 226 +/- 24 vs 417 +/- 77 fmol/gland respectively) and the SP and VIP encoding mRNAs were also decreased (8% +/- 3% and 11% +/- 4% respectively). In this group there was no detectable alteration in either the peptide or mRNA content of NPY.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, Francis Fraser Laboratory, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
authors.forename: P M
authors.initials: PM
authors.lastname: Jones
authors.forename: M A
authors.initials: MA
authors.lastname: Ghatei
authors.forename: S C
authors.initials: SC
authors.lastname: Wallis
authors.forename: S R
authors.initials: SR
authors.lastname: Bloom
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D008297:Male; D009478:Neuropeptide Y / Q000032:analysis / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011916:Rats, Inbred F344; D013373:Substance P / Q000032:analysis / Q000378:metabolism; D013963:Thyroid Hormones / Q000378:metabolism*; D013965:Thyroidectomy; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000032:analysis / Q000378:metabolism
chemical_list: D009478:Neuropeptide Y; D009479:Neuropeptides; D013963:Thyroid Hormones; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D013972:Thyrotropin; D013974:Thyroxine