GnRH-associated peptide (GAP) is cosecreted with GnRH into the hypophyseal portal blood of ovariectomized sheep

• Published in: Biochemical and biophysical research communications Vol. 143; no. 2; p. 665
• Main Authors: Clarke, I J, Cummins, J T, Karsch, F J, Seeburg, P H, Nikolics, K
• Format: Journal Article
• Language: English
• Published: United States 13-03-1987
• Subjects: Animals; Female; Gonadotropin-Releasing Hormone - metabolism; Hypothalamo-Hypophyseal System - blood supply; Hypothalamus - metabolism; Luteinizing Hormone - blood; Ovariectomy; Periodicity; Protein Precursors - metabolism; Sheep
• ISSN: 0006-291X
• DOI: 10.1016/0006-291X(87)91405-7

The secretion of gonadotropin-releasing hormone (GnRH) and GnRH-associated peptide (GAP) into sheep hypothalamo-hypophyseal portal blood was investigated in ovariectomized ewes. GAP and GnRH were cosecreted into portal blood as determined in pooled 'peak' and 'trough' samples. The temporal pattern of GAP secretion into portal blood was coincidental with that of luteinizing hormone (LH) secretion into peripheral blood in three individual animals. The data provide the first evidence that GAP is a secretory product from mammalian hypothalamus and establish the temporal coexistence of the two peptides which appears to be of physiological significance in the regulation of pituitary function.