Estrogens modulate the circadian rhythm of hypothalamic beta-endorphin contents in female rats.

The aim of the present study was to evaluate the changes in the diurnal rhythm of the hypothalamic beta-endorphin (beta-EP) contents in female rats as a function of circulating estrogens. With this purpose we evaluated the diurnal hypothalamic beta-EP changes (1) during the estrous cycle, and (2) in ovariectomized rats with and without acute and chronic estrogen replacement. Ovariectomized rats were treated either acutely with 10 micrograms of estradiol benzoate (EB) or chronically with 2 micrograms/day of EB for 15 days. beta-EP concentrations were measured in acid extracts of medial basal hypothalamus by a specific radioimmunoassay. During the estrous cycle, hypothalamic beta-EP concentrations showed a significant nocturnal increase, with no difference between the 4 days of the cycle. On the day of estrus, beta-EP concentrations between 12.00 and 18.00 h resulted significantly lower than in the other days of the cycle. After ovariectomy, the night-related changes in hypothalamic beta-EP disappeared. The acute administration of EB induced a significant increase in hypothalamic beta-EP after 21 h (18.00 h). On the other hand, the chronic replacement restored the nocturnal peak of hypothalamic beta-EP (18.00, 21.00, 24.00 h). The present data emphasize the role of central beta-EP in regulating the reproductive functions. Moreover, the effect of estrogen in modulating the circadian changes in hypothalamic beta-EP supports the important role of estrogens in brain function.

Melanosis of the larynx: a case report.

A case of diffuse melanosis, associated with an epidermoid carcinoma of the larynx, is reported. The case appears to be unique, the pigmentation being detectable at the gross examination.

The effect of melatonin and other indole derivatives in maintaining ovulation in rats kept in continuous light and the influence of these indoles on HIOMT activity in the pineal gland.

The aim of the present study was to investigate whether the ovulation-maintaining effect of melatonin in rats, exposed to continuous light (LL), was also exerted by other pineal indoles which have been reported to influence the reproductive processes of mammals. The effect of 10 micrograms melatonin was compared with that of similar amounts of either N-acetylserotonin, 5-methoxytryptophol, 5-methoxyindole-3-acetic acid, 5-hydroxytryptophol, 5-methoxytryptamine or 5-methoxytryptophan. All these compounds appeared to be significantly less effective than melatonin in preventing the effect of LL, ovulation being preserved in only 20--33% of the rats investigated, with melatonin this percentage being 60--75%. Investigations were also carried out to assess the effect of these indole derivatives on HIOMT (hydroxyindole-O-methyl transferase) activity in synthesizing different 5-methoxyindoles in the abnormally influenced pineal gland due to LL. Melatonin, the compound the effect of which on ovarian cyclicity is strongest, stimulates 5-methoxytryptophol synthesis; while other less active compounds stimulate the synthesis of melatonin and inhibit that of O-acetyl-5-methoxytryptophol. The possibility that the effect of other indoles than melatonin on ovarian cyclicity might be due to stimulation of melatonin synthesis was considered. A possible functional relationship of the different indoles cannot be excluded.

Changes in pituitary LHRH incorporation during the rat estrous cycle, and in rats made anovulatory by various experimental procedures.

Variations in anterior pituitary incorporation of LHRH in various experimental conditions have been investigated by administering tritiated LHRH. The pretreatment of animals with unlabelled LHRH significantly decreased the isotope incorporation in the pituitary gland. On the other hand, the incorporating capacity of the glands appeared to significantly change in relation to the different phases of the estrous cycle, the higher grade of radioactivity being detectable during the diestrous and proestrous phases. However, the amount of 3H-LHRH incorporated in the pituitary gland of rats bearing different types of constant estrous-anovulatory syndrome did not present significant variations in relation to the procedures employed in sterilization. Only rats neonatally androgenized with 1250 micrograms testosterone propionate showed a marked decrease of the incorporating capacity of the pituitary. One can conclude that the variations in pituitary responsiveness previously demonstrated among rats with the same anovulatory states are independent of LHRH incorporating capacity of the pituitary.

Atypical hyperplasia of the prostate. A pitfall in the cytologic diagnosis of carcinoma.

The cytomorphologic features of atypical hyperplasia were studied in fine-needle aspiration biopsies of the prostate. Atypical hyperplasia material was found in 31 cases. The most usual and distinctive cytologic features of atypical hyperplasia were clustering of poorly-differentiated epithelial cells with acinic pattern and fairly regular nuclei. Another relevant feature was the lack of cytoplasmic fluorescence after acridine orange staining. These features make possible the diagnosis of atypical hyperplasia and the distinction from poorly-differentiated carcinoma. The recognition of atypical hyperplasia cells in fine-needle aspiration biopsies of the prostate is important in the avoidance of cytodiagnostic errors.

Effect of melatonin on induction of ovulation in the light- induced constant estrous-anovulatory syndrome and possible role of the brain serotoninergic system.

Continuous light (CL) induces constant estrous anovulatory (CEA) syndrome and blockade of pineal gland activity. Chronic treatment with metatonin is able to overcome the anovulatory state in about 70% of CL-CEA rats, and the luteinizing effect of melatonin is significantly counteracted either by feeding the animals with a tryptophan-poor diet or by injecting methiothepin, a blocker of central serotoninergic receptors. It appears that melatonin elicits luteinization in CL-CEA rats through the brain serotoninergic system.

Primary gastric lymphoplasmacytoid malignant lymphoma (gastric plasmacytoma): an endoscopic cytologic diagnosis.

A case of primary gastric plasmacytoma in which diagnosis was made preoperatively by an endoscopic technique is presented. Exfoliative cytology using a brush under direct visual control enabled the case to be classified as lymphoplasmacytoid malignant lymphoma. Data which favor the diagnosis of plasmacytoma are: 1) plasma cells in various stages of maturation, 2) abnormal plasma cells often in mitotic division, 3) the presence of atypical immunoblasts.

Gastric angioendothelioma: a cytologic evaluation.

A rare case of gastric angioendothelioma is presented in which diagnosis was performed preoperatively by an endoscopic technique. Exfoliative cytology using a brush under direct visual control revealed characteristics, which may well be diagnostic. Data which favor the diagnosis of angioendothelioma are: 1) elongated or polygnal cells with ill-defined cytoplasmic borders and small cytoplasmic vacuoles; 2) ovoid or rounded, nucleolated nuclei with fine chromatin network; 3) concentric disposition of the cells and, above all, the presence of small capillary-like structures.

Ovulation induced by LH-RH in rats made anovulatory by various experimental procedures.

The injection of LH-RH induced ovulation in constant estrous rats (CEA), made anovulatory either by frontal hypothalamic deafferentation (FHD), or by exposure to continuous light (CL), or by neonatal androgenization (NA) with 0.500 mg testosterone propionate (NA500). Rats neonatally treated with 1.250 mg testosterone (NA1250) were almost unable to ovulate. 100% of FHD-CEA rats ovulated in response to 10 ng LH-RH, which is 1/3 of the lowest dose able to determine 100% of full ovulation in control proestrous rats. NA500-CEA rats, on the other hand, ovulated in response to doses comparable to those effective in the controls, whereas in CL-CEA rats the doses required for full ovulation were 2-3 times higher than in the controls. The results of these experiments demonstrate that the pituitary glands of CEA rats respond to the stimulation by the specific hypothalamic releasing factor. The pituitary response, however, appears enhanced in FHD-CEA rats and markedly depressed in CL-CEA animals.

Effect of pinealectomy and of bilateral cervical ganglionectomy on serum LH levels in constant estrous-anovulatory rats.

PIP: The effects of pinealectomy or bilateral superior cervical ganglionectomy on serum luteinizing hormone (LH) levels and ovulation were studied in constant estrous-anovulatory rats bearing a frontal hypothalamic deafferentation (FHD). Ovulation returned in 65% of the animals undergoing pinealectomy or bilateral superior cervical ganglionectomy. Almost 50% of these ovulating animals showed elevated serum levels of LH on the day of vaginal proestrus, while the remainder ovulated without appreciable changes in serum LH concentrations. It is suggested that the absence of an LH peak in the latter cases was due to an insufficient sampling size. The results suggest that pinealectomy and cervical sympathectomy may result in LH release by interference with the hypothalamic and brain stem serotonergic system involved in the inhibition of LH release.^ieng

Luteinization induced by p-chlorophenylalanine treatment in constant oestrous anovulatory rats.

PIP: Luteinization induced by p-chlorophenylalanine (p-CPA) treatment in constant estrous anovulatory rats was investigated. 52 constant estrous anovulatory rats with frontal hypothalamic deafferentation (FHD) or suprachiasmatic lesions (HL) were treated intraperitoneally 4 times, on alternate days, with 300 mg p-CPA/kg. The ovaries showed fresh corpora lutea in 52.5% of FHD rats and in 58.3% of HL rats. Therefore p-CPA was able to permit the release of luteinizing hormone-releasing hormone (LH-RH) in an amount sufficient to induce luteinization throught the depletion of brain serotonin. These results indicate that the serotoninergic mechanism of the hypothalamus and/or the midbrain is an inhibitory mediator for the release of LH-RH, and the ovulation-inducing effect of pinealectomy might be mediated by the central-nervous serotoninergic mechanism.^ieng