{'fraction_non_alphanumeric': 0.02199528672427337, 'fraction_numerical': 0.018853102906520033, 'mean_word_length': 4.764705882352941, '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}}
Effect of an intrauterine silk thread in the rat on the amino acid content of the intraluminal fluid.

The mechanism ofthe contraceptive effect of an intrauterine silk thread in the rat uterus is not clearly understood. It has been suggested that such a device may act by releasing into the intraluminal fluid a blastotoxic substance which destroys the blastocyst before implantation (Batta & Chaudhury 1968a, b; Marston & Kelly, 1969; De Boer, Anderson & Melampy, 1970; Eckstein, 1970). In the present study the concentrations of amino acids in the intraluminal fluid of a horn containing a silk thread were compared to those in fluid from uteri without any devices. Cyclic adult Charles Foster rats were anaesthetized with ether and a 3/0 silk thread suture was introduced into the right horn of the uterus as described by Doyle & Margolis (1963). Fluid was aspirated from both uterine horns at oestrus and stored at —40°C until analysis. The amino acid content of the samples was determined with an Aminoacid Analyzer after precipitation of the pro¬ teins by sulphosalicylic acid. It can be seen from the that some amino acids were present only in the fluid from the uterine horn containing the silk and that the concentrations of others were increased in these samples.