Relaxant effects of parathyroid hormone and parathyroid hormone-related peptides on oviduct motility in birds and mammals: possible role of nitric oxide
| Autor: | C.G. Dacke, M. Francis, J.F. Brown, L. Martin, Tim Butler, M. Arkle, G. Opare-Aryee, M.C. Cruz |
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| Rok vydání: | 2003 |
| Předmět: |
medicine.medical_specialty
Time Factors Arginine Muscle Relaxation Uterus Parathyroid hormone chemistry.chemical_element Gestational Age Coturnix Oviducts Biology Calcium Nitric Oxide Nitric oxide Contractility chemistry.chemical_compound Mice Uterine Contraction Endocrinology Pregnancy Internal medicine medicine Animals Humans Enzyme Inhibitors Fallopian Tubes Myometrium Parathyroid Hormone-Related Protein Peptide Fragments medicine.anatomical_structure chemistry Parathyroid Hormone Oviduct Animal Science and Zoology Female Nitric Oxide Synthase Muscle Contraction |
| Zdroj: | General and comparative endocrinology. 133(2) |
| ISSN: | 0016-6480 |
| Popis: | Parathyroid hormone (PTH) and PTH-related peptides (PTHrP) have previously been shown to modulate the contractile state of numerous types of smooth muscle. The effects of N-terminal PTH and PTHrP on spontaneous in vitro contractility of oviducal smooth muscle using tissues from egg-laying Japanese quail (10–15 h post ovulation), 4 and 9 days pregnant mouse uterus were investigated. Myometrial tissues from both species contracted vigorously for several hours, when incubated in organ baths in De Jalon’s solution gassed with 5%CO2/95%O2. Contractions were enhanced in high (1.2–2.5 mM) compared with low (0.1–0.5 mM) calcium (Ca) containing media. Bovine PTH(1–34) (bPTH(1–34)), human PTH(1–34 amide) (hPTHrP(1–34) amide), and hPTHrP(1–40) caused similar concentration-related inhibition of contractions in media containing 1.2 mM Ca over a range of 10−9 to 10−7 M, whereas C-terminal hPTHrP(107–139) was devoid of such activity. Responses to bPTH(1–34) in 4 and 9-day pregnant mouse tissues were similar but hPTHrP(1–40) showed substantial loss of activity in 9-day, compared with 4-day pregnant mouse tissues. Repeated exposure of mouse uterine tissue to the peptides resulted in desensitisation of responses. The EC50 responses of mouse tissues were inhibited by the PTH/PTHrP receptor antagonist, hPTHrP(7–34) amide. Responses to bPTH(1–34) were also inhibited by both non-selective and selective neuronal nitric oxide synthase (NOS) inhibitors Nω-nitro- l -arginine methyl ester (0.01–1 mM) and 7-nitroindazole (0.01–10 μM), respectively. Both NOS inhibitors were more effective in inhibiting bPTH(1–34)-induced relaxation in the absence of l -arginine compared with in the presence of 1 mM l -arginine (a NOS substrate) in the incubation media. It is concluded that relaxant responses to N-terminal PTH and PTHrP peptides are well conserved in oviducal and uterine tissues from avian and mammalian species. The results also suggest that NO may be responsible for mediating relaxant activities of these peptides in pregnant mouse uterine tissue. |
| Databáze: | OpenAIRE |
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