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We used three putative vasoactive intestinal peptide (VIP) antagonists: 1) [4C1-D-Phe6,Leu17]VIP, 2) [N-Ac-Tyr1,D-Phe2] GRF(1-29)-NH2, and 3) VIP(10-28) to assess the involvement of endogenous VIP in the regulation of thyroid hormone secretion and thyroid blood flow (BF). We measured thyroid BF in ketamine-pentobarbital-anesthetized rats using the microsphere technique. Increases in thyroid BF induced by VIP administration (30 pmol-1.5 nmol/100 g b.wt.) were not affected by any of the three compounds tested at doses 10-100 times higher than that of VIP. These compounds (3-15 nmol/100 g b.wt.) also failed to affect basal thyroid BF or hormone secretion. Increases in pancreatic and salivary gland BFs induced by VIP (30 pmol/100 g b.wt.) were also not affected by [4C1-D-Phe6,Leu17]VIP or [N-Ac-Tyr1,D-Phe2]GRF(1-29)-NH2 (3 nmol/100 g b.wt.). These results indicate that the three compounds tested are not effective inhibitors of VIP receptors in the thyroid vasculature and, therefore, they cannot be used in the investigation of the functional significance of endogenous VIP in the regulation of thyroid BF.
M Michalkiewicz, and
L J Huffman, and
G A Hedge
November 1993,
European journal of pharmacology,
M Michalkiewicz, and
L J Huffman, and
G A Hedge
February 1986,
Endocrinology,
M Michalkiewicz, and
L J Huffman, and
G A Hedge
July 1980,
The American journal of physiology,
M Michalkiewicz, and
L J Huffman, and
G A Hedge
January 1986,
Nihon Shokakibyo Gakkai zasshi = The Japanese journal of gastro-enterology,
M Michalkiewicz, and
L J Huffman, and
G A Hedge
November 1991,
European journal of pharmacology,
M Michalkiewicz, and
L J Huffman, and
G A Hedge
August 1990,
Nihon Naibunpi Gakkai zasshi,
M Michalkiewicz, and
L J Huffman, and
G A Hedge
April 1986,
Neuropeptides,
M Michalkiewicz, and
L J Huffman, and
G A Hedge
June 1988,
Neuroendocrinology,
M Michalkiewicz, and
L J Huffman, and
G A Hedge
November 1985,
The American journal of physiology,
M Michalkiewicz, and
L J Huffman, and
G A Hedge
January 1988,
Peptides,
