{'fraction_non_alphanumeric': 0.027985074626865673, 'fraction_numerical': 0.012437810945273632, 'mean_word_length': 4.915441176470588, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Endothelin-1 within the Corpus Luteum during Spontaneous Luteolysis in the Cow: Local Interaction with Prostaglandin F2α and Angiotensin II

It is generally accepted that endothelin-1 (ET-1) is involved in the regression of the corpus luteum (CL) in cows, but there are few in vivo data available on the local release of vasoconstrictors, including ET-1. Thus, we aimed to determine in detail the local secretion of ET-1, angiotensin II (Ang II) and prostaglandin F2α (PGF2α) within the CL during spontaneous luteolysis in the cow. To observe real-time dynamics of the releasing profile of CL-derived factors, a microdialysis system was surgically implanted in the CL on day 15 of the estrous cycle and continuously perfused with Ringer's solution. Local secretion of ET-1, Ang II and PGF2α increased immediately after the onset of luteolysis (the time point when progesterone release started to decrease within the CL) and was maintained at high levels. A positive relationship was observed in intra-luteal changes among ET-1, Ang II and PGF2α release. This is the first real-time and in vivo evidence that the secretion of ET-1 together with Ang II and PGF2α immediately increases within the CL after the onset of spontaneous luteolysis. Consequently, we suggest that the activation of a local positive feedback mechanism among ET-1, Ang II and PGF2α might play a functional role in the paracrine modulation of luteolytic cascade and, simultaneously, the elevated ET-1 with Ang II and PGF2α should induce a strong vasoconstriction, thereby reducing the blood supplying the CL during spontaneous luteolysis.