Helodermin-like peptides in thyroid C cells: stimulation of thyroid hormone secretion and suppression of calcium incorporation into bone. |
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Authors: | T Grunditz, P Persson, R H kanson, A Absood, G B ttcher, C Rerup, F Sundler |
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Affiliation: | Department of Otolaryngology, Malm? General Hospital, Sweden. |
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Abstract: | Helodermin is a vasoactive intestinal peptide-like peptide in the salivary gland venom of the lizard Heloderma suspectum. Helodermin-like immunofluorescence was observed in the parafollicular (C) cells in several mammals and in the C cell homologues of the chicken ultimobranchial gland. Thus, helodermin-like peptides coexist with calcitonin. The results of radioimmunoassay agreed with the immunocytochemical findings. HPLC of rat thyroid extracts revealed one major peak of helodermin-like immunoreactivity, which eluted in a position close to that of lizard helodermin. Helodermin stimulated basal thyroid hormone secretion and colloid droplet formation in conscious mice. The effect of large doses of helodermin was quite long-lasting and the maximal response occurred after 2-6 hr. In addition, helodermin suppressed the incorporation of calcium into bone in conscious rats. The findings suggest that helodermin-like peptides in C cells may be involved in the local regulation of thyroid hormone secretion and in the maintenance of calcium homeostasis. |
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