Normal age-dependent values of serum insulin growth factor-I: results from a healthy Italian population.

Serum IGF-I levels were measured in 547 non-hypopituitaric, non-acromegalic healthy subjects of both sexes in Italy to develop reference values in relation to age and sex. Participant subjects were stratified in three age classes (25- 39, 40-59 and >or=60 yr) and IGF-I assay was carried out by double-antibody radio immunoassay. Pearson's correlation coefficient between age and IGF-I values was calculated by sex and predefined age ranges. IGF-I levels significantly decreased with age (p<0.001, Kruskal-Wallis test) while sex was not a significant factor. The median IGF-I levels were 206 ng/ml in the 25-39 yr range, 147 ng/ml in the 40-59 yr range and 103 ng/ml in the >or=60 yr range. Pearson's correlation coefficient confirmed the negative correlation between age and IGF-I levels in the total sample of subjects (r=-0.529). The r coefficient between age and IGF-I levels did not differ between sexes (r=-0.570 in males and r=-0.529 in females), thus reflecting no sex-effect on IGF-I levels decline over years. No correlations were found in the 25-39 yr range (r=-0.036) or in the 40-59 yr range (r=-0.080) either, while in subjects aged >60 yr, IGF-I levels tended to further decrease with increased age (r=0.389). Ranges of normal values set at the 2.5th-97.5th percentile in the three age ranges were 95.6-366.7 ng/ml between 25 and 39 yr, 60.8-297.7 ng/ml between 40 and 59 yr and 34.5-219.8 ng/ml in subjects aged >or=60 yr. This study may contribute to the development of age-specific reference ranges for IGF-I determination in serum of normal subjects of both sexes in Italy.

Effects of dihydrotestosterone and hydroxyflutamide on androgen receptors in cultured human breast cancer cells (EVSA-T).

The purpose of our study was to evaluate the effects of 5 alpha-dihydrotestosterone (DHT) and hydroxyflutamide (HF), alone or in combination, on androgen receptor (AR) dynamics and on cellular growth in cultured breast cancer cells (EVSA-T). The incubation of cells with DHT increased the concentration of nuclear AR after 24 and 48 h. HF was also able to promote the nuclear accumulation of AR after 24 and 48 h of treatment. When HF-treated cells are incubated with DHT, the nuclear AR concentration is lower than that found in cells treated with DHT alone. We conclude that HF acts by increasing nuclear accumulation of receptor-antiandrogen complexes. Moreover, DHT stimulates cell growth while HF has an inhibitory effect. Thymidine incorporation in cells also increased after DHT treatment and decreased after HF incubation. The HF-induced inhibition of cell growth persisted both after renewal of the medium and after the addition of DHT to cultures. It may be hypothesized that either DHT is converted to inactive metabolites or that HF exerts a persistent inhibitory effect. In the latter case, the antiandrogen action of HF could be exerted by retention of high levels of antiandrogen in cells or by such a depressed protein synthesis that the renewal of growth is slower than the 48 h period studied.

Relationship between PRL levels and steroid receptors in breast cancer.

The role of PRL in human breast cancer is still debated. We examined 259 women undergoing surgery for breast cancer (K = 183) and for other diseases (n = 76). In all subjects blood samples were taken for the RIA assay of PRL, during the preanaesthesia. In the breast cancer specimens, estrogen (ER) and progesterone (PGR) receptors were assayed and T.N.M. was evaluated. PRL mean values were assayed and T.N.M. was evaluated. PRL mean values were found to be above the normal range in both groups. PRL values in ER+ and PGR+ were lower than in ER- and PGR-. We also divided the patients into two groups (PRL values greater than 50 or less than 50 ng/ml). The difference between the two groups was significant for ER (p less than 0.005) and PGR (p less than 0.05), using Student's unpaired t-test. Besides this, we observed a significant negative linear correlation between PRL values and receptor values. The finding of this correlation suggests that high PRL values could be associated with unfavourable prognosis in breast cancer.

Cytosolic and nuclear androgen receptors in colorectal adenomas.

The aim of this study was to verify the presence of androgen receptors (AR) in human colorectal adenomas and in normal adjacent mucosa, and to determine whether there is any difference in AR tissue content between females and males. Our data show higher levels of nuclear AR in normal mucosa than in adenomas (p less than 0.001). A significant difference was also present in males between normal and pathological tissue both in cytosolic (p less than 0.05) and nuclear receptors (p less than 0.01). In female subjects this difference was also evident, but not significant. Our results seem to support the hypothesis of protective effects of androgens in colonic mucosa.

Manipulation of the growth rate of human breast cancer cells by antiandrogen followed by chemotherapy.

The effects induced by the antiandrogen Cyproterone Acetate (CPA) on the proliferation of EVSA-T human breast cancer cells endowed with androgen receptors were studied. Kinetic analyses were carried out by two autoradiographic techniques measuring the percentage of cells in S-phase and the growth fraction (GF). The exposure of the cultures to CPA for 24 h caused a marked inhibition on S-phase cells without significantly affecting the CF. The accumulation of cells in G1-phase, confirmed by cytometric analysis, was rescued to the S compartment by replacing the culture medium 24 h after CPA administration. Exposure of EVSA-T to Doxorubicin or Methotrexate after CPA and medium change at the time of maximal proliferative recruitment, led to an enhancement of cytotoxicity as demonstrated by colony survival assay.

Responsiveness to hormone, growth factor and drug treatment of a human breast cancer cell line: comparison between early and late cultures.

Growth rate, morphology, and responsiveness to mitogenic stimuli and pharmacological treatments were evaluated in early and late cell passages derived from the same clone of the widely used MCF-7 human breast adenocarcinoma cell line. Our results indicate dissimilarities between early (E) and late (L) passages for some of the parameters analyzed. The cells that underwent many subcultivations grew faster than the others; both appeared homogeneous in size and shape. The E cells, subcultured for almost 1 yr, displayed higher sensitivity to the mitogenic action of both estradiol, according to the level of estrogen receptor, and insulin-like growth factor-I than did the L cells, kept in culture for more than 10 yr. Cell responsiveness to two drugs, a novel steroid antiestrogen and a polysulfonated distamycin A derivative, was more pronounced in the early cultures only at the longer time of exposure to the higher concentration of the estrogen antagonist. In addition, a drug-induced inhibition of insulin-like growth factor-I binding to its receptor was shown in both E and L cells, the latter being less sensitive than the former when exposed to the antiestrogen. Finally, MCF-7 E and L cells showed similar behavior when drug-induced apoptosis was tested.

Prostaglandin E2 and F2 alpha levels in the duodenal and antral mucosa of non-ulcer dyspeptic and duodenal ulcer patients.

In the present study we evaluated the contents of endogenous prostaglandins type E2 and F2 alpha in the antral mucosa, and the type E2 in the duodenal mucosa in a group of thirty non-ulcer dyspeptics in comparison with a group of thirty duodenal ulcer patients. A significantly reduced concentration of duodenal and antral PGE2 was found in ulcer patients as compared with dyspeptic subjects. A significantly increased concentration of antral PGE2 was observed in cases with active superficial antral gastritis, either in dyspeptics or in duodenal ulcer patients, as compared with normal antrum cases. A significantly increased level of PGF2 alpha was found in active superficial gastritis of the dyspeptic group.

[Behavior of the pituitary-thyroid axis in acromegalic subjects during prolonged intermittent and pulsatile treatment with octreotide]. / Comportamento dell'asse ipofiso-tiroideo in soggetti acromegalici durante prolungato trattamento intermittente e pulsatile con octreotide.

Octreotide, as well as endogenous somatostatin, inhibits GH and TSH secretion. The drug is employed in the medical therapy of acromegaly. We studied the effects of a long-term (1-120 months; median 12 months) therapy with octreotide (300 micrograms/day) given in 3-times intermittent s.c. administration or in pulsatile s.c. (25 micrograms/120 min) way, upon the pituitary-thyroid axis. Thirteen patients (11 with normal thyroid function, 1 with secondary hypothyroidism, 1 with toxic goiter) with active acromegaly were studied. In the euthyroid patients no significative variations in both TSH levels and thyroid hormones were found during octreotide therapy. In the non-euthyroid patients octreotide did not induce changes in the dosages of drugs acting to thyroid function. The 24-hour IC-TSH levels did not show any variation during octreotide. TSH response to TRH was reduced (P < 0.05) during octreotide therapy. No correlation among TSH, IGF-I and GH levels was observed. Long-term treatment of acromegaly with octreotide reduces TSH response to TRH but do not interfere with both 24-hour IC-TSH levels and thyroid function.

[An increased prevalence of thyroid echographic and autoimmune changes in hyperprolactinemic women on therapy with dopaminergic drugs]. / Aumentata prevalenza di alterazioni ecografiche e di autoimmunità tiroidea in donne iperprolattinemiche in terapia con farmaci dopaminergici.

Prolactin (PRL) possesses mitogenic and immunomodulatory properties. We evaluated the prevalence of ultrasonographic thyroid alterations and thyroid autoimmunity in hyperprolactinaemic (HPRL) women and correlated these with PRL levels. Furthermore, we studied the PRL binding in human benign nodular thyroid tissues. 133 HPRL patients (16-63 years) and 103 healthy female controls (16-63 years) with no known history of thyroid disease were studied. Blood samples were collected for PRL, FT3, FT4, TSH, thyroid peroxidase auto-antibodies (TPO Ab) and thyroglobulin auto-antibodies (Tg Ab) assays. All subjects underwent thyroid ultrasonography. PRL binding to thyroid membranes was determined by in-vitro radioreceptor assay in 5 human benign nodular thyroid fragments obtained from female patients. No difference in TSH levels was found, while FT3 (4.5 +/- 0.1 pmol/L) and FT4 (16.2 +/- 0.4 pmol/L) levels were significantly higher in controls than in HPRL (FT3: 3.8 +/- 0.1 pmol/L, p = 0.01, FT4: 15.4 +/- 0.2 pmol/L, p = 0.04). The prevalence of thyroid ultrasonographic alterations (simple goitre, uni-multinodular goitre, chronic thyroiditis) was significantly higher in HPRL (30.8%) than in controls (15.5%, p = 0.01) but did not correlate with mean initial and actual PRL levels or duration of the disease. The prevalence of autoantibodies was significantly higher in HPRL (29.6%) than in controls (14.3%, p = 0.04) but did not correlate with PRL levels. Very low specific PRL binding to thyroid membranes was detected. The high prevalence of thyroid ultrasonographic alterations and autoimmunity in HPRL suggests a possible role of PRL in the development of thyroid diseases. Clinical and instrumental thyroid screening may therefore be advisable in these patients.

Serum cytokines and steroidal hormones in polymyalgia rheumatica and elderly-onset rheumatoid arthritis.

BACKGROUND: Polymyalgia rheumatica (PMR) may create some difficulties in the differential diagnosis of elderly-onset rheumatoid arthritis (EORA) and of EORA with PMR-like onset (EORA/PMR). AIM: To investigate possible differences between three groups of patients, with regard to serum levels of inflammatory cytokines and steroidal hormones at baseline and after 1 month of treatment with glucocorticoids (prednisone 7.5-12.5 mg/day). PATIENTS AND METHODS: 14 patients with PMR, 15 with EORA and 14 with EORA/PMR, as well as 15 healthy, matched controls were analysed. Tumour necrosis factor alpha (TNFalpha), interleukin (IL)6, IL1 receptor antagonist (IL1Ra), cortisol, dehydroepiandrosterone sulphate (DHEAS) and 17-hydroxy-progesterone (PRG) were evaluated. RESULTS: Serum levels of both TNFalpha and IL6 were significantly higher in all three groups of patients than in controls (p<0.01). Serum IL6 levels were significantly higher in patients with both PMR and EORA/PMR than in patients with EORA (p<0.05). IL1Ra serum levels were significantly higher in patients with EORA than in controls (p<0.001) and in patients with PMR and EORA/PMR (p<0.05). DHEAS was significantly lower in patients with EORA/PMR than in those with EORA (p<0.05). PRG was significantly higher in all patient groups (p<0.05). After glucocorticoid treatment, serum TNFalpha and IL6 levels significantly decreased in all patient groups; IL1Ra significantly increased in patients with PMR and in those with EORA/PMR; cortisol, DHEAS, and PRG significantly decreased in patients with PMR and in those with EORA/PMR (p<0.05). CONCLUSIONS: Different cytokine and steroidal hormone patterns suggest that patients with PMR and those with EORA/PMR seem to be have a more intensive inflammatory reaction and are more efficient responders to glucocorticoid treatment than patients with EORA.

Circulating nitric oxide in women affected by weight loss amenorrhea during pulsatile gonadotropin-releasing hormone therapy.

No specific markers of the severity or prognosis of hypothalamic-pituitary-gonadal axis disturbances associated with weight loss amenorrhea (WLA) are currently available. Circulating nitric oxide (NO), which is involved in the control of the reproductive function in women and is correlated with body mass index (BMI), at least in over-weight and obese subjects, might be a marker of the severity and/or progression of WLA. To test this hypothesis, we studied circulating NO levels in 11 women (age 27.1 +/- 1.59 yr) affected by WLA for 5.1 +/- 1.0 yr; in all patients hormonal therapy had been discontinued 10.0 +/- 3.15 months earlier. NO, determined by measuring its stable catabolite nitrite/nitrates (NOx), was compared with some clinical parameters and sex hormone levels. Subsequently, changes in NOx during pulsatile GnRH therapy (120 ng/kg bw sc every 120 min) were compared with the clinical and hormonal data. Fifteen normal women (27.3 +/- 1.6 yr) served as a control group. NOx was significantly lower (p<0.01) in WLA (8.8 +/- 2.0 micromol/l) than in control (18.7 +/- 2.5 micromol/l) subjects. No correlation between NOx and clinical parameters was noted in either WLA or control subjects. As a result of GnRH therapy, ovulatory cycles reappeared in 91% of WLA women. During the 1st cycle, periovulatory 17beta-estradiol levels were 110% higher than those noted in controls. During the 2nd cycle, NOx showed a slight increase in the follicular phase (+12% vs 1st cycle) followed by a drop during the luteal phase (-40% from the follicular phase); indeed, at that time, NOx correlated negatively with progesterone in both WLA (rS -0.32, p<0.05) and control (rS -0.48, p<0.05) subjects. NOx correlated with BMI at the time of the 2nd cycle (rS 0.71, p<0.05). In conclusion, this study shows that in WLA patients: 1) NO is low, as in other conditions of chronic anovulation; 2) it does not correlate with clinical data; 3) it takes longer than sex steroids to increase and show normal-like fluctuations; 4) its fluctuations are restored earlier in patients with greater BMI.

Circadian melatonin and cortisol levels in rheumatoid arthritis patients in winter time: a north and south Europe comparison.

BACKGROUND: Altered functioning of the hypothalamic-pituitary-adrenal axis and altered melatonin production might modulate the circadian symptoms in patients with rheumatoid arthritis. OBJECTIVE: To investigate the influence of different winter photoperiods on the circadian rhythms of serum melatonin, cortisol, tumour necrosis factor alpha (TNFalpha), and interleukin 6 (IL6) in patients with rheumatoid arthritis from a north Europe country (Estonia) and a south Europe country (Italy). METHODS: The patients from Estonia (n = 19) and Italy (n = 7) had similar disease severity and duration and were compared with healthy age and sex matched controls in the two countries. Blood samples were collected during the period January to February at 8 pm, 10 pm, midnight, 2 am, 4 am, 6 am, 8 am, and 3 pm. Melatonin was measured by radioimmunoassay using (125)I-melatonin. Serum cortisol, TNFalpha, and IL6 cytokines were assayed by standard methods. RESULTS: Higher circadian melatonin concentrations from 10 pm and an earlier peak were observed in Estonian patients than in their age and sex matched controls (p<0.01). Starting from midnight, melatonin concentrations were significantly higher in the Estonian patients than in the Italian patients. No significant differences were observed for serum cortisol. Serum TNFalpha was higher (p<0.05) in Estonian patients than in their controls and was correlated with the melatonin levels. CONCLUSIONS: In a north European country (Estonia), the circadian rhythm of serum concentrations of melatonin and TNFalpha in patients with rheumatoid arthritis were significantly higher than in matched controls or in rheumatoid patients from a south Europe country (Italy).

Circulating nitric oxide levels increase after anti-androgen treatment in male-to-female transsexuals.

Circulating nitric oxide is produced by the vascular endothelium under the influence of the sex steroid milieu and shows gender difference. Since data on hormonal manipulation in males are scant, the present study was designed to evaluate nitric oxide levels before and after anti-androgen treatment in young male-to-female (MF) transsexuals. Fifteen MF transsexuals aged 23.7 +/- 1.3 yr, with normal testicular volume and normal body mass index were studied. Twenty adult males aged 28.2 +/- 2.4 yr served as controls. A low nitrate diet was administered to all subjects throughout the study, starting 15 days before the beginning. Blood samples were drawn from all subjects on day 0; flutamide 750 mg/day was then administered to transsexuals for 30 days, and another sample was taken on day 30. In all subjects the concentration of nitrite plus nitrate (NOx), two stable compounds into which nitric oxide spontaneously decomposes, was determined; also total testosterone (T) and free testosterone (fT), 17(beta)estradiol (E2), SHBG, delta4-androstenedione (A), DHEAS, 17-hydroxy-progesterone (OHP), LH, FSH and PRL were assayed. All hormones determined in controls and transsexuals were comparable at the beginning of the study. NOx was also comparable in controls (11.0 +/- 1.0 microM/l) and transsexuals (11.1 +/- 1.2 microM/l) and did not significantly correlate with any of the hormones assayed. After 30 days of flutamide administration, LH, T, fT, A and E2 increased; DHEAS decreased, while FSH, SHBG and PRL were unchanged; NOx rose significantly (18.7 +/- 1.7 microM/l; p < 0.05), and its percentage increase with respect to pre-treatment levels correlated with that of E2 (R = 0.77; p < 0.01). Healthy males and MF transsexuals do not differ in terms of sex hormones and NOx levels. In neither group is NOx significantly correlated to any sex hormone assayed. Treatment with flutamide in MF transsexuals elicits an increase in androgens, which are not biologically active because of the androgen receptor blockade, and an increase in the estrogenic milieu, which correlates with the increase in NOx.

Circulating nitric oxide changes throughout the menstrual cycle in healthy women and women affected by pathological hyperprolactinemia on dopamine agonist therapy.

The aim of the study was to evaluate circulating nitric oxide (NO) levels throughout ovulatory cycles in healthy women and women under long-term treatment with dopamine agonists. Fifty women (aged 32.5 +/- 1.2 years) affected by pathological hyperprolactinemia (prolactin (PRL)-secreting microadenoma, 63%; idiopathic, 19%; 'empty sella', 12%; and PRL-secreting macroadenoma, 6%) and on dopamine-agonist therapy (range 1-10 years) were studied; 37 healthy women (aged 30.4 +/- 1.4 years) served as a control group. Blood samples were collected on days 7, 14 and 21 of the menstrual cycle in order to assay NO, PRL, 17 beta-estradiol and progesterone. In all subjects, ovulatory cycles were recorded. PRL levels were comparable between the two groups and significantly rose during the luteal phase. NO levels recorded throughout the menstrual cycles of healthy controls were significantly higher than those recorded in subjects treated with dopamine-agonist; NO levels in the latter were no different from those recorded in non-treated, non-ovulatory hyperprolactinemic women. However, in both healthy controls and dopamine-agonist-treated women, NO was negatively correlated with progesterone concentration and significantly reduced on day 21. In dopamine-treated patients, NO levels did not correlate with the dose or the duration of dopamine-agonist therapy. We conclude that, in our hyperprolactinemic women on therapy, physiological NO secretion is not fully restored, despite restoration of ovulatory cycles by dopamine-agonist therapy.

Studies on the mechanism of the carcinogenic activity of amitrole.

Amitrole, a widely used herbicide found to produce thyroid and liver tumors in rodents and classified as possibly carcinogenic to humans, was investigated to acquire further information about its mechanism of action. A 20-hr exposure to amitrole concentrations ranging from 5.6 to 18 mM did not induce DNA fragmentation, as measured by the alkaline elution technique, in primary cultures of human thyroid follicular cells and of human liver cells. Under the same experimental conditions a minimal frequency of DNA breaks was detected in primary cultures of rat hepatocytes, but this event was presumably the unspecific consequence of a cytotoxic effect. In rats given amitrole with drinking water for 12 successive days at a daily dose of approximately 200 mg/kg, plasma levels of triiodothyronine and thyroxine displayed a progressive reduction, and a concurrent increase of both the mitotic index and frequency of S-phase cells revealing a clear-cut follicular cell hyperplasia was observed. In a group of these rats euthanized after 8 days of treatment any evidence of DNA fragmentation was absent in both thyroid and liver cells. Taken as a whole these results provide further evidence that the mechanism of amitrole carcinogenic activity is most likely nongenotoxic but due to hormone imbalance.

Changes in binding of iodomelatonin to membranes of Leydig cells and steroidogenesis after prolonged in vitro exposure to melatonin.

The aim of the present study was to investigate the effects of prolonged exposure to melatonin (MLT) on the binding of iodomelatonin to membranes of rat Leydig cells and the subsequent modulation of testosterone and cyclic adenocine monophosphate (cAMP) secretion from these cells by MLT itself. Leydig cells were Percoll-purified from adult rats and cultured in vitro with MLT (1--100 nmol/L) for 16 h. Binding assays with 2(125I)iodomelatonin were then performed; moreover, testosterone and cAMP secretion during an acute challenge with lutenizing hormone (LH) (20 mIU/mL for 3 h) was assayed by RIA. As a result of prolonged MLT administration, a decrease in maximum binding density (Bmax) and equilibrium dissociation constant (Kd) of the binding of 2(125I)iodomelatonin to purified cell membranes was noted. Higher testosterone and cAMP secretion during LH challenge were recorded in cells pre-incubated with MLT; notwithstanding, the inhibitory effect of acutely administered MLT on LH-challenged secretions was not only retained but also reinforced, as the IC50 was 30% lower in cells pre-treated with the higher concentration of MLT (100 nM). Cycloheximide administration (10 microg/mL for 16 h) did not prevent hyper-sensitization to LH challenge or to acute MLT administration on LH challenge. Pertussis toxin (180 ng/mL for 16 h) prevented hyper-sensitization to LH, but not to acutely administered MLT. Forskolin (10 nmol/L) administration abolished either phenomena. In conclusion, prolonged exposure to MLT modulates the secretion of testosterone by cultured rat Leydig cells. Although MLT receptors were reduced, hyper-sensitization to LH challenge and to acutely administered MLT on LH challenge were observed with the higher concentration of MLT. Reduction in intracellular cAMP as a result of prolonged administration of MLT, could be the primary cause of both phenomena. On the one hand, reduced cAMP could start re-arrangement of the G-proteins and thus LH-dependent adenylate cyclase sensitization. On the other hand, reduced cAMP could render the Leydig cells more responsive to MLT itself through a mechanism which does not involve G-protein re-arrangement.

Androgen receptors in normal and pathological thyroids.

The purpose of this study was to determine the presence of cytosolic and nuclear androgen receptors (AR) in both normal and nodular thyroid tissues from twelve women and six men. Samples of benign thyroid nodules and corresponding surrounding normal tissue were processed by the single saturation point assay, using [3H] R1881 ([3H] Methyltrienolone) at final concentration of 5 nM. The results show the presence of AR (cytosolic and/or nuclear) in all examined tissue samples. The nuclear AR content was higher (p less than 0.01) in normal rather than in nodular thyroid tissues. The same pattern was observed when nuclear AR were analyzed according to the sex. In addition, nuclear AR content was significantly (p less than 0.05) higher in normal thyroid tissue from men than from women. Our data suggest an androgen influence on thyroid tissue. If androgens are supposed to exert an antagonist role on estrogen actions also in thyroid tissue, the presence of higher nuclear AR concentration in the male rather than in the female normal thyroid may justify the lower incidence of thyroid diseases in men. Moreover, the lower AR levels found in male as well as in female nodular and goitrous tissues support the hypothesis that androgens may act with an antagonist mechanism on thyroid growth.

Thyroid and steroid receptors.

Estradiol and progesterone receptor proteins (ER, PgR) have been demonstrated in neoplastic and non-neoplastic human thyroid. The aim of this study was to determine the sexual steroid receptor content of pathological non-malignant thyroid (solitary adenoma, simple nontoxic goiter), and the adjacent normal tissue of the thyroid. The results show the presence of ER and PgR (cytosolic and/or nuclear) in most of examined tissues both pathological and normal. Low levels of steroid receptors are found in the cytosol fraction, whereas the receptor content is higher in the nuclear fraction. No correlation could be found between receptor levels and patients' age, menstrual state in females, and sexual steroid circulating hormones. A significant difference has been observed between adenomas and simple goiters (p less than 0.001) in the nuclear ER, and between normal tissue surrounding adenoma and normal tissue in goiters (p less than 0.05). This result suggests that estradiol and progesterone receptors are present in thyroid tissue and may have a physiological function.