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- Jörgensen, Jörgen Ch, et al.
(författare)
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The influence of neuropeptide Y and norepinephrine on ovulation in the rat ovary
- 1991
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Ingår i: Peptides. - 1873-5169. ; 12:5, s. 975-982
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Tidskriftsartikel (refereegranskat)abstract
- Neuropeptide Y (NPY) was measured in tissue extracts from ovaries of rats treated with pregnant mare serum gonadotropin (PMSG). The extracted NPY-immunoreactive material was identical to synthetic human NPY with regard to size and hydrophobicity as evaluated by gel filtration and high performance liquid chromatography. The concentration of NPY was related to the estrous cycle and a maximum was observed in relation to the endogenous luteinizing hormone (LH) peak. NPY immunoreactivity was demonstrated by immunohistochemistry to be localized within nerve fibers supplying blood vessels and follicles. The increase in the NPY content could not be related to accumulation around specific ovarian structures. Employing an in vitro set-up, NPY (10(-7) M) was unable to induce ovulation and did not increase the ovulation rate in LH-stimulated ovaries. The combination of NPY (10(-7) M) and NE (10(-7) M) did not significantly increase the number of ovulations compared to that induced by NE (10(-7) M) alone. In conclusion, NPY content in the ovary is related to the estrous cycle, but NPY does not seem to have any direct effect on the ovulatory process.
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2. |
- Liedberg, Fredrik, et al.
(författare)
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Effects of vasoactive intestinal polypeptide (VIP) on the neuromuscular complex in the bovine ovarian follicle wall
- 1993
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Ingår i: Journal of Autonomic Pharmacology. - : Wiley. - 0144-1795 .- 1365-2680. ; 13:3, s. 201-209
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Tidskriftsartikel (refereegranskat)abstract
- 1. When stimulating the local nerves in the bovine ovarian follicle wall preparation (4 Hz, 1 ms pulse duration and 7.5 V between the electrodes) vasoactive intestinal polypeptide reduced the neurogenic contraction and at the highest concentration tested (3 x 10(-7) M) almost abolished the response. Peptide histidine isoleucine only slightly reduced the contraction. 2. Strips from the follicle wall of bovine ovaries were incubated in Krebs-Ringer solution containing [3H]-noradrenaline for measurement of transmitter liberation during electrical field stimulation (5 Hz frequency, 1 ms pulse duration, 10 V between the electrodes). Vasoactive intestinal polypeptide had no effect on the electrically induced efflux of radioactivity. 3. Vasoactive intestinal polypeptide and its related peptide, peptide histidine isoleucine, relaxed precontracted follicle strips dose dependently with I(max) at 3 x 10(-7) M of 60% and 40% respectively. 4. Vasoactive intestinal polypeptide 10(-7) M did not alter the EC50 value of the noradrenaline-(10(-9)-10(-4) M) or carbachol-induced (10(-8)-3 x 10(-4) M) contraction in the follicle strips, but significantly reduced the E(max) value of the noradrenaline but not the carbochol-mediated contraction. 5. These results suggests that vasoactive intestinal polypeptide, and to some extent peptide histidine isoleucine, have a postjunctional role in ovarian follicle contractility and might further interfere with the ovulatory process.
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