S. Rubino

Effects of hormonal replacement therapy on plasma sex hormone-binding globulin, androgen and insulin-like growth factor-1 levels in postmenopausal women

Plasma sex hormone-binding globulin (SHBG) levels are important in the regulation of plasma free and albumin-bound androgens and estrogens. In postmenopausal women associated to the decrease of estrogen production, a decrease of plasma SHBG levels occurs. Hormone replacement therapy (HRT) in postmenopausal women modulates plasma SHBG levels, in relationship with the different regimens and routes of administration. The present study aimed to compare the effect of different HRT on plasma SHBG levels in relationship with the changes of plasma androgen [dehydroepiandrosterone sulphate (DHEAS), testosterone (T), androstenedione (A)] and insulin-like growth factor-1 (IGF-1) levels. In a retrospective study 443 postmenopausal women were studied and divided into 2 groups. The group 1 (n=170) was subdivided in 4 groups of women as follows: A) treated with transdermal 17-β estradiol + medroxyprogesterone acetate, B) treated with oral conjugated estrogens, C) treated with sequential HRT (estradiol valerate (EV) + norgestrel), and D) treated with a combined HRT (micronized estradiol (E2) + noretisterone acetate). Women of group 2 (n=273) did not receive HRT and served as controls. All groups of women treated with different HRT showed plasma estradiol levels significantly higher than controls (p<0.01), showing the highest values in women treated with oral HRT. Plasma SHBG levels were not significantly different between patients treated with transdermal 17-β estradiol + medroxyprogesterone acetate and controls. On the other hand, all the groups of patients treated with oral conjugated estrogen with or without progestagens showed plasma SHBG levels significantly higher than controls (p<0.01). Plasma SHBG levels were higher in the group treated with estrogen alone than in groups of women treated with sequential or combined HRT. Plasma DHEAS, T and A levels in patients treated with different HRT regimens were in the same range of levels as control women. Plasma IGF-1 levels were not significantly affected by the various HRT regimens and remained in the same range as controls. In conclusion, plasma SHBG levels increase following oral HRT while are not affected by transdermal HRT. Plasma IGF-1 and androgen levels are not influenced from oral or transdermal HRT.

Effects of estradiol and raloxifene analog on brain, adrenal and serum allopregnanolone content in fertile and ovariectomized female rats.

Allopregnanolone is a neuroactive steroid synthesized in rat gonads, adrenal cortex, and central nervous system. It has been suggested that sex steroid hormones might influence allopregnanolone concentrations but no clear data have ever been reported. The aim of the present study was to investigate the effects of administration of 17β-estradiol (17β-E2), the raloxifene analog LY-117018 or their combination on allopregnanolone levels in fertile and ovariectomized (OVX) rats. Thirteen groups of 12 Wistar female rats each received either 17β-E2 (0.1 or 1 µg/day) or LY-117018 (25, 250, and 1,250 µg/day), or 17β-E2 1 µg/day plus LY-117018: 25, 250, and 1,250 µg/day for 14 days. The rats were then sacrificed and allopregnanolone content was assessed in the hypothalamus, hippocampus, pituitary, adrenals, and serum. Ovariectomy determined a significant decrease in allopregnanolone content in the hypothalamus, hippocampus, pituitary, and serum, while increasing it in the adrenals (p < 0.01). In OVX rats, the administration of either 17β-E2 or LY- 117018 restored ovariectomy-induced allopregnanolone changes. The administration of LY-117018 in addition to 17β-E2 to OVX animals suppressed the increase in allopregnanolone levels determined by 17β-E2 in the hippocampus, hypothalamus, and pituitary, but not in the adrenals and serum. In fertile rats, the administration of LY-117018 reproduced the effects of ovariectomy. This study shows that the raloxifene analog LY-117018 has an estrogen-like action on the central nervous system of OVX rats when administered alone, while it acts as an antiestrogen in the presence of 17β-E2, both in OVX animals treated with 17β-E2 and in fertile rats. A different effect was observed in the adrenal glands. The mechanism of action of this compound has still to be clarified.

Endocrine ,neuroendocrine and behavioral effects of oral dehydroepiandrosterone sulfate supplementation in postmenopausal women

Aging in women and men is characterized by a progressive decline of circulating dehydroepiandrosterone (DHEA) levels and its sulfate ester (DHEAS). The improvement of wellbeing described in postmenopausal women treated with DHEA suggests that this steroid may exert specific actions on the central nervous system (CNS). The postmenopausal period is associated with several neuroendocrine modifications. The decrease of circulating levels of beta-endorphin is considered a hormonal marker of those changes. The aim of the present study was to investigate neuroendocrine and behavioral effects of three months of DHEAS supplementation in postmenopausal women. Postmenopausal women (n = 22) were divided in three groups: the first group was treated with oral DHEAS (n = 8) (50 mg/day), the second treated with the same dose of oral DHEAS + transdermal estradiol (n = 8) (DHEAS) 50 mg/day, estradiol 50 micrograms/patch) and the third with transdermal estradiol alone (n = 6) (50 micrograms/day). Before and after 1, 2 and 3 months of therapy, the following circulating steroid and protein hormone levels were evaluated: DHEA, DHEAS, androstenedione, testosterone, estrone, estradiol, 17-hydroxyprogesterone, sex hormone-binding globulin (SHBG), follicle-stimulating hormone (FSH), luteinizing hormone (LH), beta-endorphin, growth hormone (GH) and cortisol, and a Kupperman score was performed. Before and after treatments, plasma beta-endorphin levels were evaluated in response to three neuroendocrine tests: (a) clonidine, an alpha 2-presynaptic adrenergic agonist (1.25 mg i.v.) (b) naloxone, an opioid receptor antagonist (4 mg i.v.) and (c) fluoxetine, a serotonin selective reuptake inhibitor (30 mg p.o.). In both groups of women treated with DHEAS, mean basal serum DHEA, DHEAS, androstenedione, and testosterone levels significantly increased after treatment, while no changes were shown in the group receiving estradiol alone. Serum estradiol, estrone, GH and plasma beta-endorphin levels significantly increased progressively for the three months of treatment, with higher levels for estrone and estradiol in subjects receiving estradiol alone or plus DHEAS. Serum SHBG, cortisol, and 17-hydroxyprogesterone did not show significant variations under any treatment. Serum LH and FSH levels showed a significant decrease in groups treated with estradiol alone or plus DHEAS at the second and third months. The Kupperman score showed that all treatments were associated with similar and progressive improvement. Before therapy clonidine, naloxone and fluoxetine stimuli failed to modify circulating beta-endorphin levels. After each of the treatments, the beta-endorphin response was completely restored and was similar, independent of the kind of therapy. Restoration of the beta-endorphin response to specific stimuli suggests that DHEAS and/or its active metabolites modulates the neuroendocrine control of pituitary beta-endorphin secretion, which may support the therapeutic efficacy of the DHEAS on behavioral symptoms.

Neuroendocrine effects of different estradiol-progestin regimens in postmenopausal women

OBJECTIVE New regimens and routes of administration of hormonal replacement therapy (HRT) in climateric women are becoming available. Since there is no information on the neuroendocrine effects of sequential combined treatment with 17 beta-estradiol and a progestin, the present study evaluated the neuroendocrine, clinical vasomotor and psychological changes before and after different sequential combined HRT regimens (17 beta-estradiol plus nomegestrol acetate, or cyproterone acetate, or vaginal progesterone). Vasomotor and behavioral effects were evaluated by using the Kupperman score, while changes in plasma endorphin (beta-END) levels were used as marker of neuroendocrine effects. METHODS Postmenopausal women (n = 30) were randomly divided into three groups (ten women for each group); all women received continuous 17 beta-estradiol (50 mg, transdermal) and each group was sequentially treated with different progestins for 12 days/month: group A, cyproterone acetate (5 mg p.o.); group B, nomegestrol acetate (5 mg p.o.); and group C, progesterone (100 mg, vaginal cream). A group of healthy fertile women (n = 8) served as control. Before and after 6 months of HRT, postmenopausal women underwent an evaluation of subjective Kupperman score and two neuroendocrine tests: (a) naloxone (4 mg i.v.) and (b) clonidine (1.25 mg i.v.). Plasma beta-END levels were measured before and at 15, 30, 45, 60 and 90 min after drug injection. Control women were studied by administering the two neuroendocrine tests only once. RESULTS Postmenopausal women before HRT showed a pathological Kupperman and no changes of plasma beta-END levels in response to the clonidine and naloxone tests score. On the contrary the increase was significant in healthy women. In each of the three groups of treated women both naloxone and clonidine tests induced a significant increase in plasma beta-END levels (P < 0.01). After 6 months of HRT, an improvement of vasomotor and psychological symptoms was shown by a decrease of Kupperman score. CONCLUSIONS The present study indicates that sequential treatment with transdermal 17 beta-estradiol and progestin, no matter which progestin was used, restores the beta-END release, improves vasomotor and psychological symptoms.

Raloxifene analog LY 117018 effects on central and peripheral beta-endorphin.

Raloxifene is a selective estrogen receptor modulator with a benzothiophene structure, that exerts an estrogen-like action on some target tissues and an anti-estrogenic action on the uterus and breasts. A limited number of data are available on the effect of raloxifene on neuroendocrine function. Since beta-endorphin (beta-EP) is considered a marker of neuroendocrine function, the aim of the present study was to evaluate the effects of a 14 day treatment with a raloxifene analog, LY 117018, on beta-EP content in the hypothalamus, hippocampus, anterior and neuro-intermediate pituitary lobe, and in the plasma of fertile and ovariectomized (ovx) rats. The effect of LY 117018 in ovx rats was compared to that of 17 beta-estradiol. beta-EP contents were measured by a specific radioimmunoassay. While ovariectomy determined a significant decrease in beta-EP levels in the anterior and neurointermediate pituitary lobe and plasma (p < 0.01), no changes of beta-EP content in the hypothalamus and hippocampus were found. The administration of 17 beta-estradiol or LY 117018 in ovx rats significantly increased beta-EP concentration in the anterior and neurointermediate pituitary lobe, in the hypothalamus and plasma (p < 0.01), though they did not significantly modify hippocampal beta-EP content. When LY 117018 was administered together with 17 beta-estradiol in ovx animals, a clear anti-estrogenic effect in all organs and in plasma was observed, resulting in significantly lower beta-EP content with respect to the group treated with 17 beta-estradiol alone (p < 0.01). The chronic administration of LY 117018 in fertile rats significantly decreased beta-EP content in the anterior pituitary, hippocampus and plasma (p < 0.01), while it increased beta-EP hypothalamic content and did not change beta-EP content in the neurointermediate lobe. In conclusion, raloxifene analog LY 117018 has an estrogen-like action on neuroendocrine opiatergic pathways when administered alone in ovx rats, while it exerts an anti-estrogen effect in fertile or in ovx rats treated with 17 beta-estradiol.

Neuroendocrine effect of a short-term treatment with DHEA in postmenopausal women

OBJECTIVES A progressive decline of plasma dehydroepiandrosterone (DHEA) levels occurs in women during aging related to the reduction of adrenocortical secretion. A specific action of DHEA on the central nervous system (CNS) is suggested by the improvement of psychological and physical well-being in postmenopausal women after DHEA supplementation. The aim of the present study was to investigate the neuroendocrine effects of short-term DHEA supplementation in postmenopausal women, evaluating changes of plasma beta-endorphin (beta-EP) and growth hormone (GH) before and after oral DHEA (100 mg/day) for 7 days in postmenopausal women (n = 6). METHODS Before and after 7 days of DHEA supplementation, postmenopausal women underwent a neuroendocrine test with clonidine, an alpha 2 presinaptic agonist for adrenergic system (1.25 mg i.v.). Basal plasma DHEA, androstenedione (A), testosterone (T), estrone (E1) and estradiol (E2) levels were evaluated before and after treatment, while plasma beta-EP and GH levels were measured before and 15, 30, 45, 60 and 90 min after clonidine injection. RESULTS Basal plasma beta-EP and GH levels did not show a significant difference before and after short-term DHEA administration, while circulating A, T, E1 and E2 significantly increased after treatment. The clonidine test induced a significant increase of plasma beta-EP levels in women after receiving DHEA supplementation but not before; conversely, plasma GM levels increased both before and after treatment. CONCLUSIONS The present study indicates that short-term DHEA supplementation in postmenopausal women is able to restore the impaired response of pituitary beta-EP to clonidine, an alpha 2 presinaptic agonist. According to these data it is possible to hypothesize that DHEA could play a role in the psychological and physical well-being of postmenopausal women acting via a restoration of neuroendocrine control of antero-pituitary beta-EP secretion.

Beta-endorphin response to oral glucose tolerance test in obese and non-obese pre- and postmenopausal women

Beta-endorphin (beta-EP) is a neuropeptide involved in several brain functions, regulating the reproductive axis and behavioral changes. Estrogens play a modulatory role on circulating levels of beta-EP in women. Previous clinical studies have demonstrated high plasma beta-EP levels in obese subjects and increased beta-EP release after an oral glucose tolerance test (OGTT) in normal or obese women. The aim of the present study was to evaluate plasma beta-endorphin levels in response to an OGTT in pre- and postmenopausal obese and non-obese women, in order to investigate if the decrease in gonadal steroid levels at menopause could modify in a different manner the control of beta-endorphin release in response to glucose administration. A group of 24 normal women (age range 45-55 years) were included in the study. The patients were subdivided in four groups of six subjects each: group A, premenopausal women with body mass index (BMI) < 25 (control); group B, premenopausal women with BMI > 25 (obese); group C, post-menopausal women with BMI < 25 (control); group D, postmenopausal women with BMI > 25 (obese). All women were studied between 8.30 and 9.00 am, after overnight fasting, and underwent an OGTT. In obese premenopausal women, basal plasma beta-EP levels were significantly higher than in non-obese women (p < 0.01). In postmenopausal women, regardless of body weight, low basal plasma beta-EP levels were found. A significant increase in plasma beta-EP levels, at 30 and 60 minutes after oral glucose ingestion, was shown in control premenopausal women. No significant modifications to OGTT were shown in plasma beta-EP levels in the other three groups of women. In conclusion, while in premenopausal women the response of plasma beta-EP levels to OGTT is maintained, in postmenopause there is a lack of response to OGTT. This suggests that beta-EP release is dependent upon gonadal steroids, while it is only in part influenced by body weight.

Hormonal Replacement Therapy, Cognitive Disturbances, and Alzheimer’s Disease

Sex steroid hormones modulate the synthesis and release of neurotransmitters and neuropeptides through the binding with specific receptors in the central nervous system (CNS). In the last ten years, several epidemiological and clinical studies have shown an impairment of psychological and cognitive functions in postmenopausal women. The withdrawal of ovarian steroid production and neuroendocrine modifications have been directly related to an alteration of the cognitive function. Clinical studies have shown that hormone replacement therapy (HRT), especially that of estrogen, plays an important role in enhancing and maintaining short-term memory and abstract reasoning in postmenopausal women, whereas the performance of nontreated postmenopausal women decreases. The most severe decline of cognitive functions occur in Alzheimer’s disease (AD) patients. The incidence of AD is higher in women than in age-matched men and the cognitive function impairment is more pronounced in women than in men. An impairment of the cholinergic neuroendocrine system is involved in the pathogenesis of cognitive disturbances and of AD due to a reduction of choline acetyltransferase activity. Cholinergic pathway modifications occur in postmenopausal women with the cessation of ovarian activity. Experimental and clinical trials suggest that estrogen reverses the decrease of choline acetyltransferase in postmenopausal women, enhances cognitive functions, and may prevent the incidence of AD. Recent studies have demonstrated that glial cells and neurons are able to synthesize neuroactive steroids, starting from cholesterol, as well as metabolizing steroid hormones originating in the adrenal gland. Neurosteroids are active in modulating stress adaptive responses and memory.