Expression of C-type natriuretic peptide in the bovine pineal gland.
Recent studies have pointed to membrane-bound guanylyl cyclases (GCs) type A and type B in the rat pineal gland, which augment levels of cyclic GMP (cGMP) in response to atrial natriuretic peptide (ANP), brain-type natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). The present report demonstrates for the first time the expression of CNP in the bovine pineal gland. The CNP prohormone transcript (unlike pre-pro-ANP) was found by reverse transcriptase (RT)-PCR in bovine pineal extracts. CNP immunoreactivity (ir) was revealed in a subpopulation of pinealocytes in situ and in nearly all pinealocytes in culture. Electron microscopic immunohistochemical investigations showed the presence of CNP-ir in cytoplasmic vesicles, providing evidence for the potential secretion of this peptide by pineal cells. Furthermore, the CNP receptor (GC-B) and GC-A (receptor for ANP and BNP) were identified by RT-PCR. Although melatonin secretion was unaffected, natriuretic peptides were able to elevate markedly cGMP production in cultured bovine pinealocytes with a rank order of potency of CNP > BNP = ANP. These findings describe a tissue CNP system in the bovine pineal gland and suggest that CNP may be a local auto- or paracrine modulator of pineal function.
Middendorff
R
R
Institute of Anatomy, University of Hamburg, Germany.
Maronde
E
E
Paust
H J
HJ
Muller
D
D
Davidoff
M
M
Olcese
J
J
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000502:physiology; D015870:Gene Expression; D006162:Guanylate Cyclase / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D008550:Melatonin / Q000378:metabolism; D020098:Natriuretic Peptide, C-Type; D010870:Pineal Gland / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D017461:Receptors, Atrial Natriuretic Factor / Q000378:metabolism*
D011506:Proteins; D012333:RNA, Messenger; D020098:Natriuretic Peptide, C-Type; D009320:Atrial Natriuretic Factor; D006162:Guanylate Cyclase; D017461:Receptors, Atrial Natriuretic Factor; C073616:atrial natriuretic factor receptor C; D006152:Cyclic GMP; D008550:Melatonin