Michela d'Istria

Cell Biology of the Harderian Gland

The harderian gland is an orbital gland of the majority of land vertebrates. It is the only orbital gland in anuran amphibians since the lacrimal gland develops later during phylogenesis in some reptilian species. Perhaps because it is not found in man, little interest was paid to this gland until about four decades ago. In recent years, however, the scientific community has shown new interest in analyzing the ontogenetic and morphofunctional aspects of the harderian gland, particularly in rodents, which are the preferred experimental model for physiologists and pathologists. One of the main characteristics of the gland is the extreme variety not only in its morphology, but also in its biochemical properties. This most likely reflects the versatility of functions related to different adaptations of the species considered. The complexity of the harderian gland is further shown in its control by many exogenous and endogenous factors, which vary from species to species. The information gained so far points to the following functions for the gland: (1) lubrication of the eye and nictitating membrane, (2) a site of immune response, particularly in birds, (3) a source of pheromones, (4) a source of saliva in some chelonians, (5) osmoregulation in some reptiles, (6) photoreception in rodents, (7) thermoregulation in some rodents, and (8) a source of growth factors.

Aggressive Behavioral Characteristics and Endogenous Hormones in Women with Bulimia nervosa

Increased aggressiveness frequently occurs in patients with bulimia nervosa (BN), but its neurobiological correlates have been poorly investigated. In this study, we investigated possible relationships between such clinical measure and blood levels of endogenous hormones in patients with BN. Morning plasma levels of testosterone, 17β-estradiol, prolactin (PRL) and cortisol were measured in 33 bulimic women and 22 healthy female controls. The eating-related psychopathology, depression and aggressiveness were rated by specific psychometric scales. Bulimic patients showed decreased plasma levels of PRL and 17β-estradiol, and increased concentrations of cortisol and testosterone. Moreover, patients scored higher than healthy controls on rating scales assessing eating-related psychopathology, depressive symptoms and aggressiveness. A significant positive correlation was found between testosterone plasma levels and aggressiveness in patients but not in controls. These findings suggest that in BN, increased plasma levels of testosterone may play a role in the modulation of aggressiveness.

ADJUVANT THERAPY WITH TAMOXIFEN IN OPERABLE BREAST CANCER: 10 year results of the Naples (GUN) study

Treatment with tamoxifen (TM), alone or in combination with cyclophosphamide, methotrexate, and fluorouracil (CMF), was used as an adjuvant to surgery in 433 patients with stage I, II, or III(T3a) breast cancer. Oestrogen receptors (ER) and progesterone (PgR) receptors were assayed in most cases. 308 premenopausal node-negative and postmenopausal node-negative or node-positive patients were randomised to receive TM, 30 mg daily for 2 years, or no further therapy. 125 premenopausal node-positive patients were randomised to receive either CMF for nine courses plus TM or CMF alone. After a median follow-up of 63 months TM significantly reduced the incidence of relapses and deaths compared with no therapy. A significant interaction between treatment effect and ER/PgR status was seen. Disease-free and overall survival were similar after treatment with CMF+ TM or CMF.

Expression of melatonin (MT1, MT2) and melatonin-related receptors in the adult rat testes and during development

It is well known that melatonin provokes reproductive alterations in response to changes in hours of daylight in seasonally breeding mammals, exerting a regulatory role at different levels of the hypothalamic-pituitary-gonadal axis. Although it has also been demonstrated that melatonin may affect testicular activity in vertebrates, until now, very few data support the hypothesis of a local action of melatonin in the male gonads. The aim of this study was to investigate whether MT1, MT2 melatonin receptors and the H9 melatonin-related receptor, are expressed in the adult rat testes and during development. A semi-quantitative RT-PCR method was used to analyse the expression of MT1, MT2 and H9 receptors mRNAs in several rat tissues, mainly focusing on testes during development and adult life. Our results provide molecular evidences of the presence of both MT1 and, for the first time, MT2 melatonin receptors as well as of the H9 melatonin-related receptor in the examined tissues, including adult testes. During development MT1 and MT2 transcripts are expressed at lower levels in testes of rats from 1 day to 1 week of age, lightly increased at 2 weeks of age and remained permanently expressed throughout development until 6 months. These data strongly support the hypothesis that melatonin acts directly in male vertebrate gonads suggesting that rat testes may be a suitable model to verify the role of indolamine in vertebrate testicular activity.

Prolactin receptor does not correlate with oestrogen and progesterone receptors in primary breast cancer and lacks prognostic significance. Ten year results of the Naples adjuvant (GUN) study

The correlation between prolactin (PRLR) and oestrogen (ER) or progesterone receptors (PgR) in breast cancer and a possible prognostic significance of PRLR at 10 year follow-up have been investigated in the Naples (GUN) adjuvant trial. A total of 308 pre- and post-menopausal patients with early breast cancer, who entered the trial from 1 February 1978 to 31 December 1983, received randomly Tamoxifen (TM), 30 mg per die for 2 years, or no therapy. PRLR status was known in 229 (74.3%) patients. Values of specific binding less than 1% were considered negative. PRLR was positive in 75/229 (32.8%). ER was assayed in 210/229 (91.7%) patients and PgR in 188/229 (82.1%). No significant correlation, by the Spearman test, was found between PRLR and ER or PgR, while ER status was highly interrelated with PgR status. By the Cox model no evidence of an independent prognostic role of PRLR on disease-free survival (DFS) was observed, nor an interaction between PRLR and adjuvant treatment with TM was found.

Influence of light and temperature on the secretory activity of the harderian gland of the green frog, Rana esculenta

1. The secretory activity of the Harderian gland in Rana esculenta varies during the year, reaching its highest activity during the hottest period (July-August). Therefore, secretion may be modulated by temperature and/or photoperiod. 2. Adult males and females were placed under several combinations of light and temperature in two different periods of the year (February and July) in order to elucidate their respective roles, if any, on the stimulation of secretion. 3. Under experimental conditions, high temperature (24 degrees C), irrespective of the photoperiod selected, stimulates secretion shown both at histological and histochemical levels. 4. Low temperature (8 degrees C) impairs secretory activity, again independently of the photoperiod selected. 5. This data suggests that the secretion of the Harderian gland in Rana esculenta is modulated mainly by temperature.

Receptors for sex hormones in the skin of the amphibia

Abstract The retention of [ 3 H]-testosterone and the occurrence of specific receptors for sex hormones in the skin of males of Rana esculenta and Triturus cristatus were studied. In R. esculenta a selective uptake of testosterone and a receptor for androgens were observed, whereas in T. cristatus only a receptor for estrogens was found. These findings suggest that the body skin may be a secondary sex character in R. esculenta .

Evidence for the involvement of prothymosin α in the spermatogenesis of the frog Rana esculenta

Prothymosin alpha (PTMA) is a small acidic protein abundantly and ubiquitously expressed in mammals and involved in different biological activities. Until now, its specific function in spermatogenesis has never been properly investigated. Recently, the isolation of a cDNA encoding for PTMA from the testis of the frog Rana esculenta has been reported: ptma transcript is highly expressed throughout the frog reproductive cycle, peaking in September/October, in concomitance with the germ cell maturation; it is specifically localized in the cytoplasm of primary and secondary spermatocytes and, at a lower level, in the interstitial compartment, in Leydig cells.In this article we support the involvement of PTMA in the meiotic phases of frog spermatogenesis. The expression of ptma mRNA increases in the testis of frogs treated with the antiandrogen cyproterone acetate, which blocks the II meiotic division and induces an increase in SPC cysts; on the contrary, it highly decreases in the testis of animals kept at 4 degrees C and treated with human corionic gonadotropin, in concomitance with the induced block of spermatogenesis and the disappearance of meiotic cells in the tubules. Furthermore, for the first time we have also evidenced by immunohistochemistry the expression of PTMA in the nuclei of secondary spermatocytes, spermatids, and spermatozoa, as well as in the cytoplasm of interstitial Leydig cells. Taken together our data suggest for an important role of PTMA in germ cell maturation and/or differentiation during R. esculenta spermatogenesis.

Inhibition of the increased 17beta-estradiol-induced mast cell number by melatonin in the testis of the frog Rana esculenta, in vivo and in vitro.

SUMMARY In the present study, we have utilized 17β-estradiol to induce the increase of mast cell number in order to verify the melatonin effect on mast cell accumulation in the frog testicular interstitium. Data obtained from in vivo experiments confirm that 17β-estradiol increases the mast cell number and indicate a melatonin-inhibitory role in their accumulation in the frog testis. In addition, melatonin interferes with the effects of estradiol on the increase of mast cell number in short-term cultured testes, and this result has also been obtained in a dose-response experiment at physiological concentration. The data suggest that melatonin acts on mast cell number directly via its local action in the frog gonads. In conclusion, our study shows, for the first time, that melatonin may interfere, probably via estrogen receptors, with the differentiation and/or proliferation of mast cells induced by estradiol treatment either in vivo or in vitro in the testis of the frog Rana esculenta.

The effects of gonadectomy and testosterone treatment on the Harderian gland of the green frog, Rana esculenta

The effects of gonadectomy and testosterone treatment on the fine structure of the Harderian gland in male and female green frogs were investigated in different periods of the year. Gonadectomy, carried out when the glands are in the lowest secretory phase (September), causes degenerative changes consisting of a reduction of the rough endoplasmic reticulum, the appearance of autolysosomes, and an increase of nuclear heterochromatin. These effects can be prevented by testosterone treatment. No castration effects are found during the recovery (November) and enhancement (April-May) phases of secretory activity. The results suggest that the frog Harderian glands sensitivity to testosterone changes during the annual cycle. The androgen dependence of the Harderian gland is correlated with the presence of androgen receptors in both male and female forgs.