The acute asymmetric effects of hemiovariectomy on testosterone secretion vary along the estrous cycle. The participation of the cholinergic system

Bilateral ovariectomy and the extirpation of the left ovary performed on the day of proestrus resulted in significantly lower testosterone levels.Compared to the anesthetized group, the effects of perforating the peritoneum unilaterally varied according to the day of the estrous cycle and the side of the peritoneum surgery was performed on. Injecting atropine sulfate (ATR) to control or anesthetized rats on D1 resulted in a significant increase of testosterone serum levels.The effects of perforating the peritoneum on testosterone levels depended on the cholinergic innervation and varied along the estrous cycle. Blocking the cholinergic system before performing unilateral or bilateral ovariectomy had different effects depending on the day of the estrous cycle. Testosterone plasma levels increased significantly when surgery was performed on the day of diestrus and dropped when surgery was performed on proestrus. Similar effects were observed when the left adrenal was extirpated from animals with the cholinergic system blocked. The results presented herein support the hypothesis of asymmetry in the ovaries' abilities to secrete steroid hormones, and that the capacity to secrete testosterone varies along the estrous cycle.During the typical estrous cycle of common mono-ovulant animals, such as women, monkeys, cows, ewes, etc., the growth of a single dominant follicle is shown by only one of the ovaries, despite exposure to pituitary gonadotropins concentrations by perfusion of both ovaries with the same peripheral blood [1,2]. In the rat, a multi-ovulant animal, the left ovary releases more ova than the right one [3]. In gilts, the activities of cytochrome-c-oxidase, beta-N-acetyl-D-glucosaminidase, and glucose 6-phosphate dehydrogenase are quite dissimilar in the corpora lutea within the same ovaries, and in those from the right and the left ovary [4]. At present, no real explanation for these differences has been published, and it is possible that differences in ovari