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V Santiemma

Publications and source records attributed to V Santiemma.

At least 19 recordsLinked to original sources
PubMed2002

Angiotensin II stimulates contraction and growth of testicular peritubular myoid cells in vitro.

Seminiferous tubule contraction, an important step in the regulation of spermatogenesis and testicular sperm output, is regulated by several agonists. In the present paper, we investigated whether angiotensin II (Ang II) may have a place among them. In binding experiments performed to assess the presence of specific receptors in rat peritubular myoid cells (TPMC), binding of (125)I-Ang II to TPMC was saturable in a time-dependent manner. Competition binding experiments performed with Losartan and PD 123319 showed that Losartan was able to inhibit the binding of (125)I-Ang II, whereas PD 123319 was ineffective. Ang II induced a dose-dependent rise in intracellular Ca(2+). Depletion of intracellular calcium stores by thapsygargin resulted in a lower rise of intracellular calcium, and the L-type voltage-operated calcium channel (VOCC-L) blocker verapamil abolished the Ca(2+) influx in rat TPMC. Altogether, these findings indicate that the Ang II-induced increase in [Ca(2+)](i) involves both extracellular influx and Ca(2+) release from intracellular stores. Ang II induced a dose-dependent TPMC contraction, and Losartan and not PD 123319 inhibited the response. Ang II-induced contraction was inhibited by adrenomedullin, previously shown to antagonize endothelin 1-provoked contraction in those cells. Ang II elicited (3)H-thymidine DNA incorporation and proliferation in a dose-dependent manner in TPMC. Losartan and both MAPK inhibitor PD 98059 and tyrosine kinase inhibitor AG18 were able to inhibit Ang II-induced (3)H-thymidine uptake and cell proliferation. In conclusion, the present study documents that angiotensin II, the active mediator of the tissue and circulating renin-angiotensin system present in the mammalian testis, induces contraction, growth and rise in intracellular calcium in rat peritubular myoid cells via angiotensin II type 1 receptors, and suggests that Ang II is involved in the paracrine regulation of the seminiferous tubule function.

Angiotensin II↗
PubMed2001

Adrenomedullin inhibits the contraction of cultured rat testicular peritubular myoid cells induced by endothelin-1.

The present study documents that adrenomedullin (AM), a vasoactive peptide originally identified in pheochromocytoma tissue and present in the testis, in vitro affects the function of testicular peritubular myoid cells (TPMC), a contractile cell type located in the seminiferous tubule wall. AM stimulated cAMP production by cultured TPMC taken from 16-day-old rats, and this effect was completely inhibited by the AM antagonist AM-(22-52) and partially by the CGRP (calcitonin gene-related peptide) antagonist CGRP-(8-37). Studies on TPMC contractile activity documented that AM inhibits TPMC contraction induced by endothelin-1 (ET-1) and that its effect is antagonized by AM-(22-52). Neutralizing AM produced by TPMC with the addition of anti-AM antibody induced a significant increase of ET-1-induced contraction. When exposed to the protein kinase A inhibitor H-89, AM inhibitory activity on ET-1-induced TPMC contraction was suppressed, whereas the nitric oxide synthase inhibitor N:(G)-nitro-L-arginine methyl esther did not modify AM activity. In conclusion, our study indicates that AM stimulates cAMP production and inhibits the contraction induced by ET-1 in TPMC in vitro, and that AM produced by TPMC has an autocrine effect. We propose that AM may have a role in the control of seminiferous tubule contraction.

Adrenomedullin↗
PubMed2001

Integrin pattern and effect on contraction in cultured testicular peritubular myoid cells.

PROBLEM: Neither the integrin pattern nor the biological functions of integrins have been extensively documented in human cultured testicular peritubular myoid cells (TPMC). The integrin pattern and the presence of some proteins of the immunoglobulin superfamily on human TPMC as well as the role of integrins in TPMC contraction were examined. METHOD OF STUDY: Integrin expression was evaluated by immunofluorescence and FACS analysis. To assess the role of integrin in TPMC contraction, human and rat cells were added to a collagen gel system and exposed to contractile stimuli. RESULTS: The immunofluorescence and cytofluorimetric analysis showed that human cultured TPMC express alpha1, alpha2, alpha3, alpha4, alpha5, alpha6, alphav, beta1, beta3, and beta4 integrin subunits, and significant amounts of intercellular adhesion molecule-1 (ICAM-1), whereas they do not present alpha4, beta2, beta7 subunits, nor intercellular adhesion molecule-2 (ICAM-2) and neural cell adhesion molecule (NCAM). The preincubation of human cells with an anti-beta1 mAb and of rat cells with a polyclonal anti-beta1 antibody inhibited TPMC contraction induced by different contractile stimuli. CONCLUSION: Our investigation documented a broad integrin pattern on human cultured TPMC as well as a role for integrins in human and rat TPMC contraction.

Adult↗
PubMed2000

Follicle-stimulating hormone, testosterone, and hypoxia differentially regulate UDP-glucuronosyltransferase 1 isoforms expression in rat sertoli and peritubular myoid cells.

Uridine diphosphoglucuronosyltransferases (UGTs) are detoxifying enzymes responsible for the metabolism of endogenous and xenobiotics compounds. UGT isoforms are widely distributed in rat tissues showing a constitutive and inducible gene expression. However, little information is available concerning UGTs expression in testis. The UGT1A1, UGT1A2, and UGT1B1 mRNAs expression in whole rat testis, in Sertoli and peritubular myoid cells in basal conditions, and after hormonal and hypoxic stimulation were investigated by reverse transcriptase-polymerase chain reaction (RT-PCR). Constitutive expression of each UGT1 isoform was present in rat testis with higher levels of UGT1A2. UGT transcripts were also detected in Sertoli and peritubular myoid cells. After FSH stimulation, Sertoli cells showed an increase in UGT1B1 mRNA expression, whereas the levels of UGT1A1 and UGT1A2 resulted unmodified. The main effect induced by testosterone was a decrease of UGT1B1 mRNA expression in peritubular myoid cells, whereas in Sertoli cells an increase in UGT1A1 and UGT1B1 was observed. In hypoxic conditions, a reduction in UGTs mRNA levels was detected in both cell types. These findings suggest that rat UGT1 isoforms are regulated in testis by hormonal and environmental factors. Thus, it was speculated that alterations in UGTs expression and/or activity may be involved in the pathogenesis of testis injury.

Animals↗
PubMed2000

[Adrenal adenoma and myelolipoma in an elderly patient with Conn's syndrome].

Adrenal myelolipoma is an uncommon benign tumor usually discovered by chance in patients with hypertension, obesity, atherosclerosis, cancer or endocrine disorders. The association with adrenal endocrine dysfunctions appears to be the most frequent. Myelolipoma has been found in patients affected by Cushing's syndrome, hyperaldosteronism, Addison's disease, virilization. We report herein a case of association, based on clinical and radiological signs, between myelolipoma and adrenal adenoma in a patient with Conn's disease. The myelolipoma was localized in the opposite adrenal gland to that of adenoma, at difference with the other cases described.

Adenoma↗
PubMed1996

Luteinizing hormone pulsatility and computer-assisted analysis of sperm features in patients with Hodgkin's disease.

The aim of this work was to characterize further the impairment of the reproductive function reported in untreated male patients with Hodgkin's disease. We evaluated the pattern of luteinizing hormone pulsatility and unconventional sperm features by computer-assisted sperm analysis (CASA) in 20 adult patients affected by biopsy-proven Hodgkin's disease before they were submitted to any therapeutic approach. Changes of luteinizing hormone pulsatility were documented and consisted mainly in an increase in pulse number in comparison with control subjects (P < 0.05). On CASA, 1/3 of the patients showed a reduction in the sperm number but, when motility, velocity and linearity of progression were evaluated, the number of patients with seminal alterations rose to 2/3. Sperm velocity and linearity were already impaired in stages I and II, whereas sperm number was reduced only in stage III. Symptomatic patients, regardless of the stage, showed a significant deterioration of all parameters. Our study supports the view that in Hodgkin's disease, before any treatment, a disorder of the reproductive system is present, both at hypothalamic/hypophysial and the gonadal level, having a pathogenesis that deserves to be elucidated by further study.

Adult↗
PubMed1996

Endothelin-1 stimulates deoxyribonucleic acid synthesis and contraction in testicular peritubular myoid cells.

In the testis, endothelin-1 (ET-1) is produced by Sertoli cells, and it has been proposed to be a paracrine factor participating in the regulation of tubular and interstitial function. The response of purified testicular peritubular myoid cells (TPMC) to ET-1 was investigated in the present study. TPMC expressed a single class of high-affinity receptors that were shown by competitive binding experiments with sarafotoxin-6c to belong to the ETA subtype. The binding of ET-1 to TPMC was followed by rapid internalization of the receptor-ligand complex. ET-1 induced a prompt rise in intracellular Ca2+ concentration that was blunted in Ca(2+)-free medium and in the presence of Mn2+ or of voltage-operated-calcium-channel (VOC) blockers, indicating that both Ca2+ mobilization from intracellular stores and extracellular Ca2+ influx were involved. Thymidine uptake was promoted by ET-1 in a time-dependent manner, and the use of cyclo[D-Asp-L-Pro-D-Val-L-Leu-D-Trp] (BQ123) reduced the incorporation of thymidine. Protein kinase C (PKC) inhibition (100 nM calphostin C) abolished the ET-1 mitogenic effect. ET-1 also promoted TPMC contraction, as evaluated in collagen lattices, in a dose-related manner, with the half-maximal response observed at 1 nM. As in the case of mitogenesis, BQ123 blunted ET-1-induced contraction. PKC inhibition abolished ET-1-induced contraction. These findings indicate that ET-1 promotes DNA synthesis and contraction of TPMC and that both effects are mediated by PKC; they suggest as well that ET-1 may have a physiological role in the interaction between Sertoli cells and TPMC.

Amino Acid Sequence↗
PubMed1996

[Alteration of luteinizing hormone pulsatility in patients with arterial hypertension].

The pattern of luteinizing hormone (LH) secretion in men with mild and moderate hypertension was studied. LH pulsatility was evaluated for eight hours in 14 male patients, who were subdivided into two groups: group A, consisting of 8 patients, whose systolic blood pressure ranged between 180-160 mmHg and the diastolic between 104-95 mmHg; group B, 6 patients whose systolic blood pressure ranged between 220 and 180 mmHg and the diastolic between 115-105 mmHg. Seven healthy adult males were evaluated as a control. The major changes of LH pulsatility in group A included an increased peak width (p < 0.05), increased peak amplitude (p < 0.001) and increased peak area (p < 0.001). In group B the changes followed the same pattern as in group A, but were more pronounced. The number of LH peaks was reduced (p < 0.01), the peak width was increased (p < 0.05), and both peak amplitude and peak area were increased as compared to the control group (p < 0.001). Our study demonstrates that the pattern of LH pulsatility is altered in essential hypertension and the main feature is represented by the prolonged duration of LH peaks and their greater amplitude. The altered pattern of LH secretion is likely to reflect a primary hypothalamic derangement with the gonadotropin releasing hormone (Gn-RH) secreting neurons remaining synchronized for longer times and secreting larger Gn-RH masses than in normal subjects.

Adult↗
PubMed1992

Human Sertoli cells in vitro: morphological features and androgen-binding protein secretion.

Sertoli cells play a pivotal role in the regulation of spermatogenesis as they provide the anatomical basis of the blood-testis barrier. In the present paper we report some results of our studies on the ultrastructural features, the responsiveness to FSH, and the ability to secrete androgen-binding protein (ABP) of human Sertoli cells in vitro. The nucleus showed the characteristic foldings of the nuclear membrane, scattered chromatin, and a fibrillar nucleolus. In the cytoplasm Charcot-Boettcher crystals were present and active phagocytic activity was documented by the presence of vacuoles containing lipids and cellular debris. Human Sertoli cells in culture responded to FSH with a maximal rise in cAMP that was approx. 3-fold. This response to FSH is comparable to that reported for the adult rat but lower than that of the immature rat, and suggests that human as well as rat Sertoli cells could have a reduced response to FSH since sexual maturation was achieved. As no evidence has been reported on ABP secretion by human Sertoli cells in culture we evaluated the concentration of this protein in the Sertoli cell spent media. Human Sertoli cells in culture produced ABP and the response to FSH was dose-related. The Kd value of human ABP (hABP) was approx. 7.5 nM, being slightly higher than that of the rat ABP and an order of magnitude different from that of sex hormone-binding globulin (SHBG) present in human plasma. We also measured the association and dissociation rates of dihydrotestosterone-hABP complexes and the Kd/Ka ratio was very close to the value of Kd of the Scatchard analysis. The differences between hABP and SHBG may open the way to the selective measurement of ABP in many conditions of male infertility.

Androgen-Binding Protein↗
PubMed1988

Patterns of lateralization and performance levels for verbal and spatial tasks in congenital androgen deficiency.

The effects of congenital deficiency of gonadal hormones on verbal and spatial performance and on the establishment of hemispheric asymmetries were investigated in a group of patients with idiopathic hypogonadotropic hypogonadism. The patients showed a left hemispheric advantage for verbal material and were mildly impaired, mainly on tasks involving a short-term memory load, in comparison with a matched control group. These results do not indicate a specific role of gonadal hormones on the establishment of hemispheric asymmetries. Lack of exposure during brain development results in a decrease in memory functions which is not specific for verbal or spatial material.

Adolescent↗
PubMed1987

Light microscopic, immunocytochemical and ultrastructural study of a case of Sertoli cell tumor of the testis.

A case of testicular specialized gonadal stroma tumor was evaluated by histologic, ultrastructural and immunohistochemical techniques in a young adult male patient. The neoplastic cells were organized in cords or tubular structures delimited by a basement membrane. The ultrastructural findings suggested a diagnosis of a partially differentiated Sertoli cell tumor. This was also supported by the presence of a vimentin rich cytoskeleton, which is normally present in Sertoli and Leydig cells. The tumor cells did not secrete steroid hormones, as suggested by clinical findings, as well as by hormonal, immunohistochemical, and ultrastructural observations.

Adult↗
PubMed1987

Lactate dehydrogenase and malate dehydrogenase of Sertoli cells in rats.

Lactate-dehydrogenase (LDH) and malate-dehydrogenase (MDH) activities and isozyme patterns of maturing Sertoli cells were investigated in cultured cells obtained from 2-5-week-old rats. Both enzymes, and more strikingly LDH, increased between 2 and 3 weeks of age. LDH isozyme complement included all five isozymes and, in the more mature rats, had a shift toward the isoforms rich in subunit. These data are consistent with an increasing production of lactate/pyruvate and with a finer regulation of this production occurring during the maturing of Sertoli cells. Since lactate/pyruvate are important energy substrates for germ cells, the changes of LDH activity and isozyme patterns of maturing Sertoli cells support their nutritional role in the seminiferous epithelium.

Animals↗
PubMed1986

Quantitative evaluation of Leydig cells in testicular biopsies of men with varicocele.

A quantitative analysis of Leydig cells was performed in 23 testicular biopsies of men with left varicocele and sperm count ranging from zero to 95,000 sperm/mm3. The oligozoospermic patients had more Leydig cells and higher FSH and LH serum levels than the patient group with more than 10,000 sperm/mm3. The Leydig cell density appeared tightly correlated (p less than 0.01) with the serum level of LH. In oligozoospermic subjects, an altered Leydig cell function could trigger an increased LH secretion; this seems likely to be responsible for the stimulation of interstitial cells resulting in an exaggerated recruitment of mature Leydig cells from their precursors. The comparative analysis of left and right testes failed to show differences in Leydig cell density and spermatogenesis in normozoospermic and oligozoospermic patients. This suggests that the two testes are equally involved by a possible, although unknown, detrimental effect of left side varicocele.

Adult↗
PubMed1984

Effects of Lonidamine on pituitary-gonadal axis in man.

Lonidamine was given for 3 weeks at the dose of 150 mg three times daily to 6 male cancer patients. Serum follicle-stimulating and luteinizing hormone levels were significantly higher as compared to pretreatment values after 1 and 3 weeks of Lonidamine administration, while testosterone, prolactin, and thyroid-stimulating hormone levels remained unchanged.

Aged↗
PubMed1981

Acute cadmium intoxication: influence of cyproterone acetate on the testis and epididymis of the rat.

The changes resulting from treatment with cadmium were studied following the histological changes, the modification of both vascular permeability to vital dyes and of alkaline phosphatase activity in rat testis and epididymis. The testicular extravasation of acriflavine started 90 min following parenteral injection of cadmium and increased thereafter synchronous with an increase in testicular and epididymal weights due to edema. At 14 and 24 hr a striking decrease of interstitial fluorescence and tubular degeneration were noted in testis and caput epididymis due to thrombosis of the microvascular circulation. The barrier noted at 8 hr following cadmium injection. No changes of alkaline phosphatase activity was detected in testicular and epididymal blood vessels after cadmium injection. Previous treatment with cyproterone acetate accelerated the appearance of such alterations. The interstitial nuclear staining with acriflavine appeared in the testis at 1 hr and was diffuse at 90 and 120 min. cyproterone acetate seemed to accelerate the appearance of tubular degeneration at 8 hr after cadmium injection. The changes of the male rat gonad following cadmium treatment were characterized by an increased vascular permeability and generalized thrombosis. An inbalance of androgen stimulation seems to increase the blood vessels susceptibility to cadmium.

Acriflavine↗