Study of the Luteinizing Hormone-Induced Increase of Ovarian Blood Flow During the Estrous Cycle in the Rat

Autor: Varga, B., Horváth, Edit, Folly, G., Stark, E.
Zdroj: Biology of Reproduction; April 1985, Vol. 32 Issue: 3 p480-488, 9p
Abstrakt: CYF rats were anesthetized on various days of the 4-day cycle and blood samples were collected at 5-min interals from the ovarian vein before and after i.v. administration of 5 μg/100 g BW of luteinizing hormone (LH). Ovarian venous outflow, blood pressure and hematocrit were continuously recorded, and from the blood samples progesterone (P) and 17β-estradiol (E2) were determined by radioimmunoassay (RIA). Ovarian blood flow and P secretion showed a parallel increase on Day 1 (estrus), on Day 2, and on the afternoon of Day 4 (proestrous). LH increased ovarian blood flow each day of the cycle together with P and E2secretion; however, no relationship was seen between the initial value of hormone secretion and the LH-induced increase of ovarian blood flow. Inhibition of hormone secretion by cycloheximide prevented the LH-induced increase of ovarian blood flow; moreover, a decrease in ovarian blood flow parallel with the diminution of hormone secretion was observed. Indomethacin pretreatment abolished the hyperemic effect of LH and partially inhibited the LH-induced increase of hormone secretion. Propranolol blocked the LH-induced increase of ovarian blood flow and blunted the effect of LH on hormone secretion.It was concluded that in LH-induced hyperemia, cAMP, prostaglandins and other vasoactive metabolites released during the process of hormone synthesis, and also a β-adrenergic mechanism, are involved in the regulation of ovarian blood flow.
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