Data/hora: 10/06/2024 15:21:33

Provedor de dados: | 19
País: | Japan
Título: | A cooperative action of endothelin-1 with prostaglandin F-2 alpha on luteal function in the cow
Autores: | Shirasuna, Koumei; Watanabe, S.; Oki, N.; Wijayagunawardane, M. P. B.; Matsui, Motozumi; Ohtani, M.; Miyamoto, Akio; 白砂, 孔明; 松井, 基純; 宮本, 明夫.
Data: | 2006-08
Ano: | 2006
Palavras-chave: | Endothelin-1; Prostaglandin F-2 alpha; Luteolysis; Corpus luteum; Cow.
Resumo: | Prostaglandin F-2 alpha (PGF(2 alpha)) is the primary luteolysin in the cow, and luteal endothelin-1 (ET-1) interacts with PGF(2 alpha) during the process of luteolysis. In contrast, a developing corpus luteum (CL) is refractory to exogenous administration of PGF(2 alpha). Thus, the present study was aimed to investigate the functional relationship between ET-1 and PGF(2 alpha) in the mid-CL (PGF(2 alpha)-sensitive) and early-CL (PGF(2 alpha)-refractory). In the mid-CL model, cows (n = 6/treatment) were assigned to receive one of five types of treatments on day 10 of the estrous cycle: (1) an injection of saline; control, (2) a 500 jig of PGF2. analogue (sufficient dose to induce luteolytis); full-PG, (3) an intraluteal injection of 0.25 mg ET-1; ET-1, (4) a 125 mu g of PGF2. (insufficient dose to induce luteolytis); 1/4PG or (5) an intraluteal injection of 0.25 mg ET-I after administration of a insufficient dose of PGF2. analogue; 1/4PG/El In the early-CL model, cows were assigned to receive one of two types of treatments on day 5 of the estrous cycle: (1) a sufficient dose of PGF2. analogue; PG (n = 5) or (2) an intraluteal injection ET-I after a sufficient dose of PGF(2 alpha); PG/ET (n = 7). In the mid-CL model, 1/4PG/ET resulted in a rapid reduction of progesterone (P) concentrations similar to that in full-PG from the next day. However, the levels of P in 1/4PG/ET (1.5-2.5 ng/ml) kept significantly higher than that in full-PG (&lt; 0.5 ng/ml). ET-1 or 1/4PG did not decrease plasma P concentrations (4-6 ng/ml). The plasma ET-1 levels increased with the full-PG administration. In the early-CL model, both treatments had no effect on plasma P increase and ET-1 levels. The overall results indicate that the intraluteat ET-1 injection after administration of insufficient dose of PGF(2 alpha) induces the depression of P secretion in vivo during the mid luteal phase in the cow, supporting the concept that ET-1 is one of a local mediator of functional luteolysis in the cow. The result further indicates that the early-CL is not only PG-reftactory but also ET-1-refractory.
Idioma: | Inglês
Identificador: | http://ir.obihiro.ac.jp/dspace/handle/10322/825
Editor: | ELSEVIER SCIENCE INC
Formato: | application/pdf