Biomedical subjects

A Lanzone

Publications and source records attributed to A Lanzone.

At least 109 records · Page 6Linked to original sources

PubMed1995

The growth hormone response to growth hormone-releasing hormone is blunted in polycystic ovary syndrome: relationship with obesity and hyperinsulinaemia.

This study was designed to investigate the growth hormone (GH) secretory response to the growth hormone-releasing hormone (GHRH) test in women with polycystic ovary syndrome (PCOS). A total of 25 patients with PCOS (13 obese and 12 non-obese) and 15 normal ovulatory women (seven obese and eight non-obese) were included in this study. In the follicular phase patients were subjected to an oral glucose tolerance test (OGTT); 2 days later they underwent a GHRH test. Basal plasma concentrations of gonadotrophins, steroids and sex hormone-binding globulin were measured. Insulin and GH were assayed under the OGTT and GHRH test respectively. Based on the insulin response to OGTT in the PCOS group, nine patients were classified as normoinsulinaemic and 16 as hyperinsulinaemic; none of the patients of the control group had a hyperinsulinaemic response to OGTT. Obese patients showed a trend towards a lower GH response to GHRH. Moreover, hyperinsulinaemic patients showed a significantly (P < 0.05) lower area under the curve for secretion of GH (AUC-GH) as compared to normo-insulinaemic patients. All PCOS patients exhibited a markedly decreased response of GH to GHRH compared with the control population. Obese and hyperinsulinaemic PCOS patients were both found to have a lower response of GH to GHRH than all other groups. Despite the fact that obesity and hyperinsulinaemia have an additive influence on the impairment of GH secretion, our results suggest that other factors may also negatively affect GH secretion in PCOS.

Adult↗

PubMed1995

Epidermal growth factor receptors in placentae and fetal membranes from hypertension-complicated pregnancies.

Epidermal growth factor receptor concentrations (EGFR) in placentae and fetal membranes from 25 normal and 25 hypertension-complicated pregnancies were analysed by a radioreceptor technique. Higher EGFR concentrations were found in placentae from hypertension-complicated pregnancies than in those from normal pregnancies (median 125.0 fmol/mg protein, range: 33.4-190.7 versus median 50.3 fmol/mg protein, range 21.4-184.0) (P = 0.0002). EGFR concentrations were significantly lower in fetal membranes than in placental tissue, both in normal membranes (median 31.7, range 4.8-92.0 versus median 50.3, range 21.4-184.0) (P = 0.0004) and in hypertension-complicated pregnancies (median 65.0, range 16.8-125.0 versus median 125.0, range 33.4-190.7) (P = 0.0001). A statistically significant inverse correlation between EGFR concentrations and gestational age was found in placentae (r = 0.53, P = 0.0061) and fetal membranes (r = 0.56, P = 0.0032) from hypertension-complicated pregnancies. Multiple regression analyses demonstrated that hypertensive disease is more closely associated with EGFR concentrations than gestational age and fetal weight in placental tissue and fetal membranes. Our findings suggest that hypertensive disorders in pregnancy are associated with elevated EGFR concentrations in both the placenta and fetal membranes.

Epidermal Growth Factor↗

PubMed1995

Somatostatin action on rat ovarian steroidogenesis.

To date, very few studies on the effect of somatostatin on female reproductive function have been reported. In our study, we examined the effects of somatostatin on (i) androgen biosynthesis using whole ovarian dispersates, and (ii) aromatase activity and progesterone production using granulosa cells. Whole ovarian dispersates obtained from immature rats were cultured for 96 h in serum-free medium with human chorionic gonadotrophin (HCG; 25 ng/ml) and insulin (10 micrograms/ml) in the presence or absence of an increasing concentration of somatostatin (0.03-3.00 ng/ml). HCG- and insulin-stimulated accumulation of androsterone by these cells was inhibited significantly by somatostatin. Granulosa cells from diethylstilbestrol-treated rats were cultured for 48 h in serum-free medium with follicle-stimulating hormone (FSH; 20 ng/ml) and FSH plus insulin (1 microgram/ml) with or without somatostatin (0.03-3.00 ng/ml). Both aromatase activity and progesterone production stimulated by FSH and FSH plus insulin were significantly inhibited by somatostatin. Somatostatin by itself (1 ng/ml) did not have an effect on any of the evaluated parameters. The action of somatostatin could be immunoneutralized and did not influence the plated viable cell mass. These findings indicate that somatostatin can regulate ovarian steroidogenesis by mediating gonadotrophin and growth factor action on different ovarian cell types.

Androgens↗

PubMed1995

Effect of opioid blockade on insulin metabolism in polycystic ovarian disease.

A total of 17 women affected by polycystic ovarian disease (PCOD) were studied to evaluate the involvement of endogenous opioids in the pathophysiology of the hyperinsulinism in PCOD by administering naltrexone, an oral opioid antagonist. An oral glucose tolerance test (OGTT) was performed at baseline (on day 5 of the cycle) and repeated after 6 weeks of naltrexone administration. Plasma glucose, insulin and connecting peptide (c-peptide) concentrations were evaluated in all samples. Based on their insulinaemic response to OGTT, patients were classified as hyperinsulinaemic or normoinsulinaemic. Naltrexone treatment significantly (P < 0.007) reduced the insulin response to OGTT in the hyperinsulinaemic group without affecting the c-peptide incremental area; in the normoinsulinaemic group there was a slight, but not significant, increase in both c-peptide and insulin incremental areas. The two groups showed similar c-peptide incremental areas after naltrexone treatment. There was no significant difference in the c-peptide:insulin incremental areas molar ratio between the two groups; after treatment, a significant increase in this ratio was observed in both groups. When we considered the data as an expression of the fractional hepatic extraction of insulin, we found a lower value for hyperinsulinaemic in comparison with normoinsulinaemic patients (not significant), and a significant (P < 0.01) improvement of this parameter in the hyperinsulinaemic group after naltrexone administration. In conclusion, we suggest that the contribution to hyperinsulinaemia in PCOD patients may be at least in part due to both increased pancreatic secretion and reduced hepatic removal of insulin. Chronic pharmacological inhibition of opioid tone could improve the insulin plasma concentration by acting chiefly on the liver metabolism of insulin in hyperinsulinaemic patients.

Adolescent↗

PubMed1995

Evidence of a distinct derangement of opioid tone in hyperinsulinemic patients with polycystic ovarian syndrome: relationship with insulin and luteinizing hormone secretion.

Recent data indicate that an altered opioid tone could be involved in the LH hypersecretion and metabolic alterations seen in polycystic ovary syndrome (PCOS). The aim of the present study was to investigate the presence of a common mechanism of action of opioids on altered insulin and gonadotropin release in patients suffering from PCOS. Twenty-eight women affected by PCOS and 8 normal ovulatory women were studied; an oral glucose tolerance test (OGTT) and GnRH tests were performed during the follicular phase before and after 6 weeks of naltrexone treatment (50 mg/day, orally). Plasma levels of sex hormone-binding globulin and steroids were assayed in the basal samples, whereas FSH and LH were analyzed during the GnRH stimulus. Insulin and glucose were assayed by the OGTT. Based on the insulinemic response to OGTT, 17 women were classified as hyperinsulinemic and 11 as normoinsulinemic. No difference in glucose and hormone plasma concentrations was observed before and after naltrexone treatment in both groups. Only basal sex hormone-binding globulin values were higher in normoinsulinemic compared to hyperinsulinemic subjects. Administration of the opioid antagonist significantly reduced the insulin response to OGTT only in the hyperinsulinemic group. No difference were found in the LH increment after the GnRH stimulus in both group of patients before treatment; on the contrary, naltrexone administration reduced the LH response to GnRH in hyperinsulinemic women but failed to be effective in normoinsulinemic subjects. Only 5 patients showed no concordance of drug-induced changes in insulin and LH secretion. In control subjects, naltrexone failed to have any effect on insulin or LH secretion. These data support the involvement of endogenous opioids in the regulation of insulin and LH secretion in a specific group of PCOS patients exhibiting an exaggerated insulin response to OGTT.

Adult↗

PubMed1995

In vitro human growth hormone increases human chorionic gonadotropin and progesterone secretion by human placenta at term: evidence of a modulatory role by opioids.

We examined the in vitro effect of human growth hormone (hGH) on hormone placental production and the modulation by opioids of this function. Small placental fragments from 12 term placentas were incubated at 37 degrees C in a 95% air and 5% CO2 atmosphere for 4 h with various concentrations of hGH (1-1000 ng/ml) or naloxone (3-500 ng/ml). Both hGH and naloxone increased the concentrations of human chorionic gonadotropin (hCG) and progesterone in the media. The effect of the hGH was dose-dependent and statistically significant at 10 ng/ml, while naloxone was able to increase hCG and progesterone production only at the highest doses (250-500 ng/ml). The concomitant treatment with ineffective doses of naloxone and hGH was able to enhance hCG and progesterone secretion reaching levels similar to those obtained with the highest doses of hGH alone. High naloxone concentrations significantly decreased both hCG and progesterone secretion induced by high doses of hGH. This study confirms the relevance of growth hormone in sustaining placental endocrine activities and indicates an effect of opioids in modulating these functions.

Chorionic Gonadotropin↗

PubMed1995

Effect of corticotropin-releasing factor on the pituitary-ovary axis in human luteal phase.

In order to test the possible negative effect of corticotropin-releasing factor (CRF) on the pituitary-gonadal axis, two gonadotropin-releasing hormone (GnRH) tests, on two consecutive days, were performed in five normally cycling women in the midluteal phase of the menstrual cycle. The first GnRH test was performed after 2 h during which time basal blood samples were collected every 10 min. On the second day, the GnRH test was repeated after a 2-h CRF infusion which was continued throughout the GnRH test. Our results demonstrate that while CRF increases cortisol levels it affects neither the basal nor the GnRH-stimulated gonadotropin levels. Similarly, both basal and luteinizing hormone (LH)-stimulated progesterone concentrations were not modified by the CRF infusion thereby also excluding a possible direct effect of the peptide on corpus luteum steroidogenesis.

Adult↗

PubMed1995

Polycystic ovary disease. A risk factor for gestational diabetes?

We investigated the impact of pregestationally elevated insulin plasma levels on glycemic control in pregnant women with polycystic ovary disease (PCOD). Twelve patients with PCOD who became pregnant within six months following evaluation of their metabolic status were the study subjects. Four were obese and six (two obese) had a hyperinsulinemic response to the oral glucose tolerance test (OGTT). They were tested with the OGTT at 28-30 weeks of gestation. We also tested 12 normal patients and 10 consecutive patients with gestational diabetes; all were at the same gestational age. Plasma levels of insulin and glucose were determined in the samples collected for a period of four hours after glucose load (100 g). All PCOD patients significantly increased their insulin secretion in pregnancy. The hyperinsulinemic PCOD patients developed gestational diabetes (two patients) and impaired gestational glucose tolerance (three patients). The area under the insulin curve was greater in PCOD patients than in control and gestational diabetes patients (P < .01). In spite of their large increase in insulin secretion observed during pregnancy, patients with PCOD may develop a derangement of glycemic control, probably related to their pregestational insulinemic status.

Analysis of Variance↗

PubMed1994

Growth hormone induction of rat granulosa cell tissue-plasminogen activator expression and progesterone synthesis.

The plasminogen activator (PA) system is present in the ovary and appears to be involved both in follicular growth and ovulation. Similarly, the growth hormone (GH) has been demonstrated to positively affect some ovarian activities. Interestingly, GH appears not only as a mediator of gonadotropin effects, but also as having an independent action of its own on the ovary. In the present study we wanted to investigate if GH could affect ovarian plasminogen activator (PA) activity and steroidogenesis. Granulosa cells from immature rats, injected with pregnant mare serum gonadotropin (PMSG) for inducing follicular growth, were cultured for 24 h with increasing concentrations of GH. A significant dose-dependent increase in tPA activity was observed in the GH-treated cells. This effect was exerted at the mRNA level and the use of cycloheximide, a protein synthesis inhibitor, suggested that GH did not require any other intermediary protein for inducing tPA-mRNA. Furthermore, cAMP levels were not affected by GH treatment. Finally, GH was found to increase progesterone (P) synthesis by granulosa cells. The correlation between the PA system and ovulation and the importance of a normal steroidogenesis for the ovarian physiology claim for a key role of GH in the ovarian activities.

Animals↗

PubMed1994

Effect of gonadotropins, insulin and IGF I on granulosa luteal cells from polycystic ovaries.

The aim of this work is to evaluate the gonadotropin and growth factor effects in vitro on steroidal response in human granulosa luteal cells from polycystic ovaries compared with normal granulosa luteal cells in humans. The granulosa cells from polycystic (polycystic ovarian granulosa cells, POGC) and normo-ovulating women (normal cells, NC) were collected in the preovulatory phase after oocyte retrieval during the GIFT program. The cells were cultured serum-free for 24, 48 and 96 h. Estradiol and progesterone production was determined with or without HCG (1-200 ng/ml), FSH (10-300 ng/ml), insulin (1-50 micrograms/ml) and IGF I (1-50 ng/ml) addition. All treatments significantly induced a 2-3 fold estradiol increase at the 48-h and 96-h time points in POGC. The progesterone production was unaffected by HCG, FSH, insulin and IGF I addition, respectively, in POGC, whereas the NC were responsive at the 48-h and 96-h time points. FSH did not stimulate progesterone production in granulosa cells either from polycystic or normovulating subjects. Our findings indicate that POGC are hypersensitive to all substances in terms of estradiol production, whereas they show a reduced capacity of progesterone production with some treatments.

Adult↗

PubMed1994

Growth hormone induces in vitro maturation of follicle- and cumulus-enclosed rat oocytes.

The aim of this study was to assess the possible role of growth hormone (GH) on rat oocyte maturation. This effect was analyzed in follicle-enclosed, cumulus-enclosed and denuded oocytes obtained from immature pregnant mare's serum gonadotropin (PMSG)-treated rats. The addition of GH to the cultures significantly accelerated maturation in both follicle- and cumulus-enclosed oocytes while no effect was seen on denuded oocytes maturation. Also, GH accelerated meiotic maturation in follicle-enclosed oocytes from immature untreated rats. The GH action was not mediated by lactogenic receptors since prolactin (Prl) did not affect the maturation process while it was mediated by insulin growth factor-I (IGF-I) as suggested by the block of GH action observed in the presence of antibodies anti-IGF-I. Finally, no GH effect was found when dbcAMP was added to the cultures. Our results demonstrate that GH is capable of inducing maturation in oocytes from both primed and unprimed rats. Since the presence of physiological levels of GH in the ovary is now well established, the present data strongly suggest a potential relevance of GH in the reproductive biology.

Animals↗

PubMed1994

Gonadotropin-releasing hormone agonist versus human chorionic gonadotropin as a trigger of ovulation in polycystic ovarian disease gonadotropin hyperstimulated cycles.

OBJECTIVE: To compare the use of GnRH agonist (GnRH-a) versus hCG in triggering the follicular rupture in patients with polycystic ovarian disease (PCOD) in whom ovulation was induced by gonadotropins. DESIGN: Polycystic ovarian disease gonadotropin hyperstimulated cycles outcome was investigated in a prospective study. PATIENTS AND INTERVENTIONS: Thirty-three PCOD patients (40 cycles) with gonadotropin-induced mild to moderate degree of ovarian hyperstimulation received 5,000 IU IM hCG or 200 microg [corrected] SC GnRH-a. A subgroup of GnRH-a-treated patients received P for luteal support. Five GnRH-a-treated patients underwent a GnRH test during luteal phase. MAIN OUTCOME MEASURES: Echographic and endocrine characteristics both during the therapy and the luteal phase. RESULTS: There was a similar percentage of ovulation and pregnancy rate in both groups of patients. The ovarian enlargement during the luteal phase in the GnRH-a-treated patients was lower than in the hCG group. Progesterone plasma levels (at midluteal phase) and the length of luteal phase was significantly lower in GnRH-a-treated patients with respect to the hCG-treated group. These differences disappeared in patients receiving luteal support. After GnRH injection, LH secretion decreased in GnRH-a-treated patients with respect to controls; however, corpus luteum was able to respond with a normal increase of P production. CONCLUSION: The GnRH-a appears to be an effective alternative to hCG for inducing the follicular rupture in stimulated cycles in women who are at risk for developing ovarian hyperstimulation syndrome. However, GnRH-a administration can induce short luteal phase. This defect may be ascribed to the pituitary desensitization rather than to a direct effect on corpus luteum. Luteal phase support is needed to prevent luteal phase deficiency.

Adult↗

PubMed1994

Effect of activin-A on progesterone synthesis in human luteal cells.

OBJECTIVE: To examine the effect of activin-A on basal and hCG-stimulated P production by human luteal cells. DESIGN: Mixed luteal cell cultures and distinct cultures of two luteal cell types: small and large luteal cells from early and midluteal phase. SETTING: Corpora lutea (CL) were obtained from the Obstetrics and Gynecology Department of the Catholic University, Rome, Italy. PATIENTS: Fifteen nonpregnant women between 30 and 45 years of age underwent surgery for nonendocrine gynecological diseases. INTERVENTIONS: Corpora lutea were obtained at the time of hysterectomy. The luteal cells were dispersed in Ham's F-12 medium containing collagenase at 37 degrees C in shaking water bath for 2 hours, filtered, centrifuged, and resuspended in fresh medium. MAIN OUTCOME MEASURES: The cells diluted to a final concentration of 60,000 to 100,000 cells/mL of medium. After 24 hours, the cells attached to the wells and were incubated with or without hCG and/or activin-A at different concentrations. RESULTS: Activin-A starting from 25 micrograms/L significantly decreased basal and hCG (250 mIU/mL [conversion to SI unit, 1.00])-induced P production by mixed luteal cells. The small luteal cells responded to hCG (250 mIU/mL), and the treatment with activin-A (from 25 to 100 micrograms/L) reduced their basal and hCG-induced P production. Activin-A addition did not change the amount of P release by large luteal cells at any concentration. CONCLUSIONS: These results imply that activin-A plays a role in the local regulation of human CL.

Activins↗

PubMed1994

Differential androgen response to adrenocorticotrophin hormone stimulation and effect of opioid antagonist on insulin secretion in polycystic ovarian syndrome.

To investigate the effect of a chronic anti-opioid treatment on the adrenal steroid production in polycystic ovarian syndrome (PCOS), 20 women affected by PCOS were studied before and after 6 weeks of treatment with an opioid antagonist. All women had an oral glucose tolerance test (OGTT) (75 g) on day 5 of the cycle. At 11.00 p.m. 2 mg of dexamethasone was orally administered and blood samples collected the following day at 7.00 a.m. Then 250 micrograms of adrenocorticotrophin hormone (ACTH) was injected i.v. and samples collected 60 min later. At this time a 6 week course of naltrexone treatment (50 mg/day orally) was started, following which the protocol was repeated on day 6-7 of the menstrual cycle. According to OGTT responses, 10 patients were classified as hyperinsulinaemic and 10 as normoinsulinaemic. No difference in baseline hormone concentrations was found, except for sex hormone-binding globulin, which was significantly greater in normoinsulinaemic patients (P < 0.02). The plasma concentration of all steroids after dexamethasone and ACTH administration was similar in both groups, except for androstenedione (P < 0.02) and 17 alpha-hydroxyprogesterone (17-OHP) (P < 0.05), which were significantly greater after ACTH injection in hyperinsulinaemic compared with normoinsulinaemic PCOS patients. Naltrexone treatment significantly (P < 0.001) reduced insulin response to OGTT in the hyperinsulinaemic group, while it did not affect the response in the normoinsulinaemic group; thus at the end of the treatment the two groups had the same insulin concentrations. Similarly, naltrexone abolished the difference between normoinsulinaemic and hyperinsulinaemic patients regarding androstenedione and 17-OHP response to ACTH.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗

PubMed1994

Insulin secretion in patients with gestational diabetes: relationship with pregnancy outcome.

The authors observed that there is wide variability in insulin response to an oral glucose tolerance test in women developing carbohydrate intolerance during pregnancy. This variability ranges from a reduction of pancreatic islet function to a normal or exaggerated secretory pattern of insulin. Moreover the results also suggest that exaggerated insulin secretion and/or high insulin resistance may play a role in the regulation of gestational blood pressure and that a higher glucose/insulin ratio may be positively related to birth weight. Clearly, further studies are needed to investigate the impact of this metabolic situation on the optimization of the clinical control of glucose metabolism and fetal homeostasis.

Adult↗

PubMed1994

In vitro production of plasminogen activator by human granulosa cells.

Plasminogen activator (PA) production by granulosa cells has been demonstrated in several species. In the human ovary, tissue-type PA and urokinase-type PA antigens have been found in the follicular fluids, but neither PA activity nor mRNA for both enzymes was found in granulosa cells of preovulatory follicles. All of these studies were performed on granulosa cells collected from follicles immediately before ovulation, when the cells were already in the luteal phase. In the attempt to better characterize the PA/plasminogen system in the human ovary, we examined PA and PA inhibitor (PAI) production in cultures of granulosa cells obtained from normally cycling untreated women at different stages of the cycle. In addition, we analyzed granulosa-luteal cells obtained from hormonally stimulated women undergoing gamete intrafallopian tube transfer, as a model of late phase follicular development. Zymographic analysis as well as immunoprecipitation with specific antisera revealed that granulosa cells from follicles at early phases of antral stages secreted high levels of PA of the urokinase type in the medium. No free tissue-type PA activity was found in any of the examined samples. On the contrary, free PAI was undetectable in medium obtained from granulosa cell cultures, and it was abundant in granulosa-luteal cell cultures, where it was found in two forms. These data show that in the human ovary as in that of the rat, PAs and PAIs are tightly time regulated. The timing of PA production in human granulosa cells suggests a role for PA activity at early stages of follicular maturation.

Adult↗

PubMed1993

Ovarian sensitivity to follicle-stimulating hormone during the follicular phase of the human menstrual cycle and in patients with polycystic ovarian syndrome.

OBJECTIVE: To investigate the existence of a different sensitivity of ovaries to follicle-stimulating hormone (FSH) during the follicular phase of the human menstrual cycle and in patients with polycystic ovarian syndrome (PCOS). DESIGN: Thirty-four normal subjects and 13 patients with PCOS were treated intravenously by FSH (75 or 225 IU) or saline at different stages of follicular phase. MAIN OUTCOME MEASURES: Plasma levels of luteinizing hormone (LH), FSH, estradiol (E2), and testosterone (T) in samples collected for a period of 26 hours after the injection. RESULTS: In patients at the early stages of follicular phase (baseline E2 < 50 pg/mL), FSH increased in dose-dependent manner E2 and E2:T-stimulated area under curve (AUC) in respect to saline experiments. In PCOS subjects, saline E2, and E2:T-stimulated AUC were significantly lower than normal women. Follicle-stimulating hormone (75 IU) dramatically increased these values, and no difference was seen in respect to 75 and 225 IU FSH-treated controls. In patients with E2 baseline plasma levels > 50 pg/mL, FSH (75 or 225 IU) failed to increase both E2 and E2:T-stimulated AUC in comparison with saline studies. CONCLUSIONS: Early stages of follicular phase in normal and polycystic ovaries are the most responsive to the elevation of circulating FSH levels, whereas the ovarian sensitivity spontaneously decreases as follicular maturation enhances.

Adult↗

PubMed1993

Long-term naltrexone treatment normalizes the pituitary response to gonadotropin-releasing hormone in polycystic ovarian syndrome.

OBJECTIVE: To investigate the influence of opioid system on the exaggerated LH response to GnRH test in the polycystic ovarian syndrome (PCOS). DESIGN: Pituitary stimulation (GnRH 100 micrograms) in a group of PCOS patients under basal condition and after 4 weeks of treatment with naltrexone. RESULTS: In the PCOS group, the naltrexone treatment determines a significant reduction of the LH response (calculated as the area under curve) to GnRH test, with a similar significant decrease of the LH:FSH. CONCLUSION: Naltrexone normalizes in the PCOS group the pituitary response to GnRH test, abolishing every statistical differences with the control group.

Adolescent↗