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Objective To examine the distribution of mast cells in human uterine tissue and to study the interactions between mast cell mediators (histamine and serotonin) and PGF,, in human myometrium contractile activity.Design Distribution of mast cells were analysed in cryostat sections of myometrium samples stained with Toluidine blue. Contractile activity was evaluated in an isolated organ bath preparation on myometrial strips obtained from women whose pregnancies ended in elective caesarean section.Setting Biological Science Laboratories at the University of Concepci6n.Subjects Twenty women undergoing elective caesarean and 10 women undergoing hysterectomy at the G. Grant Hospital.Main outcome measurements Cumulative concentration-response curves for histamine and serotonin before and after the addition of subumbral concentrations of the PGF,, or serotonin were performed.

Different studies in ovariectomized estrogen treated animals support the idea that cfos plays a role in the proliferation of uterine epithelial cells. However, these studies invite us to reassess the role played by c-fos in epithelial cell types of the endometrium during the estrous cycle. The present study was undertaken to determine the c-fos and estrogen receptor (ER) gene expression pattern in the rat uterine epithelium during the estrous cycle in which natural and cyclic changes of steroid hormones occur, and correlate these changes with the proliferation status of this cellular types. Proliferation was assessed during the estrous cycle using bromodeoxyuridine incorporation to DNA. ERa and b proteins were assessed by immunohistochemistry. The regulation of c-fos gene expression in the uterus of intact animals during the estrous cycle was evaluated using both in situ hybridization and immunohistochemistry. Estradiol (E 2 ) and progesterone (P 4 ) plasma levels were assessed by radioimmunoassay. The results indicated that luminal (LE) and glandular epithelia (GE) presented maximal proliferation during the metestrus (M) and the diestrus (D) days. However, during the proestrus (P) day only LE presented proliferation, and during the estrus (E) day only the stromal cells proliferated. A marked immunostaining for ERa was detected in both LE and GE cells during the early phases of the cycle but diminished on the P and the E day. In contrast, ERb was undetectable in both epithelia during all stages of the cycle. The highest cfos mRNA level was detected in both epithelia on the M day, followed by a significant reduction during the other days of the cycle. The highest protein content was observed on the M and D days, and the minimal value was detected on the E day. The c-Fos protein level in LE was increased during M and D days, presenting a high correlation with the cellular proliferation pattern of this cell type. In conclusion, the overall results indicate that c-Fos protein presented a good correlation with uterine epithelial cell proliferation of LE. In the case of GE, the same tendency was observed, although no significant correlation was found. Both in LE and GE, c-fos mRNA did not strictly correlate with its protein levels. c-fos seems to have a postranscriptional regulation in uterine epithelial cells during the rat's estrous cycle. Mol. Reprod. Dev. 64: 379-388,

The possible existence of peripheral asymmetry in the neuroendocrine mechanisms participating in the response of the ovary to gonadotrophins, and the participation of the vagus nerve, was investigated. At oestrus, the ovulation rate (number of ovulating/number of treated rats) of the left ovary in right unilaterally ovariectomized rats was lower than that in the right ovary in left unilaterally ovariectomized rats (42 vs 84%). No differences in the number of ova shed per ovulating animal nor in compensatory ovarian hypertrophy (COH) were observed. Bilateral section of the vagus nerve resulted in reduced COH only in those animals with the left ovary in situ (right unilaterally ovariectomized). Section of the left vagus nerve induced different effects depending upon which ovary was left in situ. When the left ovary was in situ an increase in ovulation rate, COH and number of ova shed was observed; however, when the right ovary was left in place the above three parameters decreased. Section of the right vagus nerve produced a decrease only in COH in both right and left unilaterally ovariectomized animals. It is concluded that in the unilaterally ovariectomized rat the right ovary seems more able to react to compensatory regulatory systems than does the left. The character of the information carried by the left and right vagus nerve is different.

The acute effects of hemiovariectomy on progesterone, testosterone, estradiol, and luteinizing hormone (LH) concentrations in serum were studied in rats under the following experimental conditions: control, shamoperated (left or right), hemiovariectomized, bilateral adrenalectomized, and hemiovariectomized plus bilateral adrenalectomized. One-hour after surgery, the concentration of progesterone and testosterone in the serum of right-side sham-operated rats was significantly higher than in control animals. Testosterone concentration in serum in rats with the right ovary in situ was higher than in sham-operated animals; injecting atropine sulfate 1 h before surgery blocked such increase, while the same treatment to rats with the left ovary remaining in situ resulted in a significant increase of testosterone concentration. Adrenalectomy resulted in an increase of testosterone concentration, which was higher when atropine sulfate was injected before surgery. Our results support the idea that left and right ovaries play different roles in the regulation of hormone secretion, and that such differences are related to ovarian innervation.

The effects were analysed, on ovulation at the next oestrus, of unilaterally implanting atropine in the anterior hypothalamus of rats on each day of the oestrous cycle. Implantation on day 1 of dioestrus on either side of the anterior hypothalamus blocked ovulation. Implantation on the left side of the hypothalamus on day 2 of dioestrus blocked ovulation in all animals, whereas implantation on the right side allowed 71% of the animals to ovulate (0/4 vs 5/7; P less than 0.05). Implantation at pro-oestrus on either side of the hypothalamus did not modify the rate of ovulation. When implantation was carried out on the day of oestrus on the right, none of the animals ovulated, but all ovulated when the implant was on the left (0/8 vs 8/8; P less than 0.01). The results suggest the existence of a cholinergic hypothalamic lateralization in the mechanism regulating ovulation which depends on the day of the oestrous cycle.

This study was designed to analyze the acute effects of unilateral or bilateral ovariectomy or adrenalectomy, performed on different days of the estrous cycle, on progesterone (P4) serum levels 1 h after surgery. The effects of blocking the cholinergic system by injecting atropine sulfate were also analyzed. Ether anesthesia treatment on diestrus 1 (D1) increased P4 serum levels. Compared to right sham-operated animals, right ovariectomy (left ovary in situ) performed on diestrus 2 (D2) or proestrus (P), resulted in P4 serum levels increase. Compared to animals with left sham surgery, left adrenalectomy (right adrenal in situ) performed on P day resulted in significantly lower P4 concentrations. Bilateral adrenalectomy resulted in a significant drop of P4 serum levels; the most remarkable drop was observed in animals treated on D2. Bilateral ovariectomy performed on D1 resulted in lower P4 serum levels, and the same treatment performed on P resulted in a significant rise of P4 serum levels. Injecting atropine sulfate to untouched (control group) rats resulted in significantly higher P4 concentrations. Blocking the cholinergic sys-tem on D1 or P to rats with the right adrenal removed resulted in lower P4 serum levels; while, in contrast, atropine sulfate treatment performed on D2 resulted in P4 serum levels increase. The results support the hypothesis of asymmetry in the ovaries' and adrenals' capacities to secrete P4; that this capacity varies along the estrous cycle; and that P4 secretion by the ovaries and adrenals is regulated by the cholinergic system.

The present study analyzed the participation of the left and right superior ovarian nerves (SON) in regulating progesterone, testosterone, and estradiol serum levels in unilaterally ovariectomized rats on each day of the estrous cycle. For this purpose, ovarian hormone concentrations in serum were measured in animals with either sham-surgery, unilateral ovariectomy (ULO), unilateral sectioning of the SON, or sectioning of the SON innervation of the in situ ovary in rats with ULO.This investigation results show that the right and left ovaries have different capacities to maintain normal hormone levels, that such capacity varies during the estrous cycle, and that it depends on the integrity of the SON innervation. In rats with only one ovary, the effects of ovarian denervation on hormone levels varied according to which ovary remained in situ, the specific hormone, and the day of the estrous cycle when treatment was performed. Present results support the idea that the ovaries send and receive neural information that is processed in the central nervous system and we propose that this information participates in controlling the secretion of gonadotropins related to the regulation of ovarian functions.