Maternal adrenalectomy eliminates a surge of plasma dehydroepiandrosterone in the mother and attenuates the prenatal testosterone surge in the male fetus.

Previous work has established a number of sex-related deficits in immune function, behavior, and endocrine responses to stress in the offspring of dams exposed to ethanol. To examine the potential role of maternal glucocorticoids as a mediator of these sexually dimorphic effects in the fetus, we examined the influence of prenatal alcohol exposure in the presence or absence of maternal glucocorticoids on fetal plasma corticosterone (CORT) production. An additional question to be addressed by these studies was whether maternal adrenalectomy could eliminate the known inhibition by ethanol of the prenatal surge of plasma testosterone in male fetuses. Pregnant dams were adrenalectomized (ADX) or sham-adrenalectomized on gestational day (G) 7 and placed on a liquid diet containing 35% ethanol-derived calories or pair-fed an isocaloric control diet throughout the experiment. On G18, G19, and G21, plasma levels of CORT, testosterone, and dehydroepiandrosterone (DHEA) were measured in male and female fetuses and their mothers. Ethanol administration consistently increased maternal plasma CORT levels but did not significantly alter CORT levels in the fetus. Maternal ADX resulted in compensatory increases in fetal CORT levels that were lower in fetuses of ADX dams on alcohol, suggesting a direct effect of ethanol on fetal pituitary-adrenal activity. There were no significant sex differences in fetal plasma CORT levels in response to any of these manipulations. A novel surge of maternal plasma DHEA was found on G19 that was absent in plasma from ADX dams. In spite of the absence of a surge on G19, plasma DHEA levels of ADX dams rose from very low levels at G18 to levels on G21 that were significantly higher than in Sham dams. A normal testosterone surge was observed in male fetuses on G18 and G19 from sham-adrenalectomized dams administered the pair-fed diet. However, this surge was greatly attenuated in males administered ethanol and also in male fetuses from ADX dams. These results reveal a direct inhibitory influence of ethanol on fetal CORT secretion as well as on the prenatal testosterone surge in males. Furthermore, these studies demonstrate the presence of a surge of DHEA in the pregnant rat. Overall, these data suggest that there is a critical adrenal factor in the rat that regulates the maternal surge of DHEA on G19 and the prenatal testosterone surge of male fetuses on G18-19.

Pituitary irradiation is ineffective in normalizing plasma insulin-like growth factor I in patients with acromegaly.

Pituitary irradiation suppresses GH hypersecretion in patients with acromegaly. Within 10 yr after radiotherapy, up to 80% of patients achieve plasma GH levels below 5 micrograms/L. Whether this is sufficient to normalize plasma insulin-like growth factor I (IGF-I) levels, is unknown. We examined the effect of radiotherapy on plasma IGF-I concentrations in patients with acromegaly. We reviewed hospital charts of 140 patients with acromegaly seen in our institution between 1975 and 1996. Data on plasma GH and IGF-I were extracted and tabulated longitudinally together with the information about the concomitant medical therapy. We included data from the patients who received radiotherapy as a part of their treatment and whose IGF-I was monitored for more than 1 yr afterward. To avoid the potential bias, the data for patients who were referred to us for medical therapy, having failed radiation elsewhere, were excluded. A total of 38 datasets were submitted for the final analysis. The average follow-up was 6.8 +/- 0.8 yr (range, 1-19). Only 2 patients achieved age- and sex-adjusted normal IGF-I levels while off medical therapy. Noncured patients had a mean plasma GH level of 4.6 +/- 1.1 micrograms/L but still elevated plasma IGF-I levels (219 +/- 26% of the upper normal limit) at the last follow-up visit. A random GH concentration below 1.5 micrograms/L was associated with a pathologically high plasma IGF-I concentration in 43% of instances. Radiotherapy appears to be ineffective in normalizing plasma IGF-I levels in acromegaly. A multicenter study to reevaluate the future use of this modality in patients with acromegaly is warranted.

Sexually dimorphic effects of maternal adrenalectomy on hypothalamic corticotrophin-releasing factor, glucocorticoid receptor and anterior pituitary POMC mRNA levels in rat neonates.

The stress hyporesponsive period (SHRP) occurs during the first two weeks of life (from day 4 to day 14) in the rat. SHRP may occur due to immature hypothalamic-pituitary-adrenal (HPA) regulatory mechanisms of the neonate. Decreased expression of corticotropin-releasing factor (CRF) has been observed during this period, and this decreased hypothalamic 'drive' may contribute to the manifestation of SHRP in the rat neonate. Since maternal corticosteroids are elevated toward the end of gestation they may suppress fetal CRF expression leading to a less than adequate activation of the neonatal hypothalamus in response to stress. Therefore, the purpose of the present study was to clarify the contribution of maternal glucocorticoids to the decreased CRF expression observed during SHRP in the neonatal rat. We investigated the effects of maternal adrenalectomy on hypothalamic CRF, glucocorticoid receptor (GR) and anterior pituitary proopiomelanocortin (POMC) mRNA levels in male and female neonates. Maternal adrenalectomy, or sham surgery, was performed on day 8 of gestation and the mRNA levels of CRF, GR and POMC were measured by Northern blotting in the offspring on their postnatal days 1, 7, 14, and 21. The observed changes in the mRNA levels of these genes suggests that an important developmental event occurs in the regulation of these HPA genes between neonatal days 7 and 14 corresponding to the termination of SHRP. Female offspring had significantly higher levels of CRF mRNA than males throughout this period. The lack of maternal corticosteroids evoked a gender-specific response in the neonates. In female offspring, maternal adrenalectomy resulted in a dramatic and correlated increase in mRNA levels of hypothalamic CRF and GR on day 14, with pituitary POMC expression not following this increase. There was no significant effect of maternal adrenalectomy on the expression of these genes in males. These results suggest a sex difference in response to maternal glucocorticoids in the fetus. However, the role of maternal corticosteroids in the low expression of CRF during SHRP could not be established from this study, since their removal by adrenalectomy did not advance the expression profile of CRF toward an earlier increase in the neonatal hypothalamus.

Corticotropin-releasing hormone and proopiomelanocortin gene expression is altered selectively in the male rat fetal thymus by maternal alcohol consumption.

The present study was carried out to investigate how hormonal changes caused by chronic alcohol exposure of rats during the late period of gestation are coordinated with neuroendocrine functions of the fetal thymus, namely thymic expression of CRH and POMC genes. Alcohol consumption by pregnant dams led to a 5-fold elevation of plasma corticosterone (CORT) levels and significantly decreased fetal CORT levels. This generally inverse correlation between maternal and fetal CORT was absent in alcohol-consuming dams and their male fetuses on day 19 of gestation. These day 19 fetuses also had an attenuated plasma testosterone surge that occurred in the male control (pair-fed) fetus on day 19 of embryonic life. Furthermore, fetal alcohol exposure (FAE) resulted in a significant increase in thymic CRH and a decrease in thymic POMC expression in the male fetuses only, specifically on embryonic day 19. Thus, the strong positive correlation between CRH and POMC gene expression in the thymus of pair-fed male and female FAE fetuses was abolished in the FAE males. However, regardless of embryonic age or treatment, a strong positive correlation between thymic POMC gene expression and plasma testosterone levels in the male fetuses was detected. These data suggest that the sexually dimorphic effect of FAE on the fetal thymic POMC and CRH expression in males is driven by testosterone and may be related, therefore, to the presence of alcohol at the time of the prenatal testosterone surge in the male fetuses.

Ontogeny of hypothalamic corticotropin-releasing factor and anterior pituitary pro-opiomelanocortin expression in male and female offspring of alcohol-exposed and adrenalectomized dams.

This study was designed to determine whether the previously described sexually dimorphic changes in rat hypothalamic corticotropin-releasing factor (CRF) and anterior pituitary pro-opiomelanocortin (POMC) mRNA expression in response to fetal alcohol exposure (FAE) are present prepubertally and whether they are altered by maternal adrenalectomy. Hypothalamic CRF and anterior pituitary POMC mRNA levels were determined in male and female offspring of adrenalectomized (ADX) and sham-adrenalectomized (Sham) dams exposed to alcohol (FAE) or a pair-fed (PF) control diet during the last 2 weeks of gestation. CRF and POMC mRNA levels were measured by Northern blotting at 1, 7, 14, and 21 days of age. In offspring of control PF dams, CRF mRNA levels increased faster in females, increasing by day 7, followed by a decrease at days 14 and 21, whereas in males there was a gradual increase from days 1 to 21. FAE altered the ontogenic profile of CRF mRNA in female offspring by delaying and exaggerating the rise of CRF expression to day 14, but produced no effect in males. Maternal adrenalectomy, combined with FAE, resulted in an early rise of CRF mRNA on day 14 in male offspring. In females, the combined ADX/FAE treatment resulted in significantly increased CRF mRNA levels, compared with those of ADX/PF offspring, on days 7 and 14. By day 21, these differences in CRF mRNA levels between the ADX/FAE and ADX/PF offspring had disappeared. POMC mRNA levels generally increased by day 7, followed by a dramatic decrease by day 14 and another increase by day 21. FAE male offspring showed decreased levels of POMC mRNA, whereas females were not affected. Maternal adrenalectomy reversed this inhibition in male offspring, resulting in POMC mRNA levels similar to those measured in male offspring of PF control animals. In contrast, POMC mRNA levels of female offspring of ADX dams decreased in response to FAE. These data suggest that the previously observed switch from suppressed to enhanced POMC expression in FAE males is the result of developmental events beyond weaning. Because this sexually dimorphic regulation of CRF and POMC expression by prenatal alcohol exposure and maternal adrenalectomy occurs before the presence of adult levels of sex steroids, this suggests an organizational effect on the developing hypothalamic-pituitary-adrenal function.

Fast glucocorticoid feedback inhibition of ACTH secretion in the ovariectomized rat: effect of chronic estrogen and progesterone.

The purpose of this study was to determine whether estrogen and progesterone influence fast glucocorticoid negative feedback regulation of the ACTH and corticosterone (CORT) responses to stress. Mature rats were ovariectomized and 6 weeks later implanted with 17 beta-estradiol (E2, 0.5 mg), E2 and progesterone (P, 100 mg; E2 + P group) or placebo pellets (OVX). Seven days later rats were subjected to a single or repeated intermittent footshock stress (0.2 mA, 15 s duration, 0.5 s on). The repeated stress was of the same intensity and duration, and was applied either during the time domain of the rate-sensitive fast glucocorticoid feedback when plasma CORT levels are rising (5 min after the onset of the first stress), or at the time of peak CORT response (15 min) to the initial stress. Plasma ACTH and CORT were measured from serial samples. Estrogen replacement alone or in combination with progesterone lowered the immediate (t = 5) ACTH and CORT response to a single stress in ovariectomized animals. The second stress applied 5 min after the initial stress produced net ACTH responses similar to those obtained after a single stress in the OVX and E2 + P-replaced hormone groups, while total ACTH responses were lower in the E2-treated group. In ovariectomized animals, a facilitation of ACTH response by a prior stress is apparent in response to a footshock 15 min later, when the integrated ACTH secretion is significantly greater than the response measured after a single shock, or after a repeated shock 5 min apart. Anterior pituitary proopiomelanocortin (POMC) mRNA levels were lower in groups with E2 or E2 + P replacement compared to OVX animals. In contrast, hypothalamic corticotropin-releasing factor (CRF) mRNA levels did not increase significantly. However, hypothalamic glucocorticoid receptor (GR) mRNA levels increased after 17 beta-estradiol treatment, and this increase was reversed by progesterone. These results suggest that prior stress leads to both a fast-feedback inhibition and a facilitation of the subsequent stress response. In the absence of gonadal hormones this facilitation is balanced by fast-feedback inhibition during the glucocorticoid fast-feedback time domain, and is unmasked outside of this time domain. Estrogen suppresses POMC mRNA synthesis leading to a decrease in the availability of releasable ACTH, thereby reducing the facilitation. Progesterone may counter this effect of estrogen by decreasing the efficacy of the fast rate-sensitive glucocorticoid negative feedback.

Maternal adrenalectomy alters the immune and endocrine functions of fetal alcohol-exposed male offspring.

Exposure to ethanol in utero compromises the offspring's developing immune and endocrine systems. Persistent functional changes, particularly in T-cell-dependent aspects of immunity and in hypothalamic-pituitary-adrenal activity, are commonly seen. The present study examined the degree to which fetal alcohol exposure (FAE) during development suppressed the lymphocyte proliferative response to Concanavalin-A (Con A). We also examined the effect of maternal adrenalectomy on the expression of glucocorticoid-regulated genes and the response to Con A in FAE offspring. Con A-stimulated lymphocyte proliferation was stably suppressed (between 28-46%) in FAE males compared to isocalorically pair-fed offspring at 7, 21, 40, and 60 days of age. In contrast, lymphocyte proliferation in the immature or peripubertal FAE female was totally unaffected. In 60-day- old male rats, maternal adrenalectomy reversed the FAE-induced suppression of Con A-stimulated proliferation, but had no effect on lymphocyte proliferation. FAE increased anterior pituitary POMC (the precursor of ACTH) mRNA levels dramatically in males, and this increase was also reversed by maternal adrenalectomy. In both sexes, anterior pituitary glucocorticoid receptor mRNA levels were unaffected by prenatal alcohol exposure alone, but were significantly decreased in male and increased in female offspring of adrenalectomized dams ingesting alcohol. Furthermore, in male, but not female, offspring, hypothalamic levels of glucocorticoid receptor and CRF mRNA were increased significantly by FAE alone or in combination with maternal adrenalectomy. In female, but not male, offspring, maternal adrenalectomy with concomitant alcohol exposure increased anterior pituitary POMC mRNA levels compared to that in sham/pair-fed offspring. In summary, FAE induced a gender-specific impairment of Con A-stimulated lymphocyte proliferation. This deficit is present both before and after puberty, demonstrating its stability into adulthood. Furthermore, in males, maternal adrenalectomy reversed these FAE-induced deficits in T-cell function as well as the effect of FAE on anterior pituitary POMC expression. This supports the hypothesis that maternal adrenal hormones participate in the immunosuppressive "imprinting" of the FAE fetus and are, therefore, causally implicated in the sexually dimorphic T-cell dysfunction found in FAE offspring.

Sexually dimorphic effects of alcohol exposure in utero on neuroendocrine and immune functions in chronic alcohol-exposed adult rats.

Maternal ethanol consumption has deleterious effects on the offspring's neuroendocrine and T-cell-dependent functions. Chronic alcohol consumption in adulthood has also been associated with activated hypothalamic-pituitary-adrenal (HPA) function and immunosuppression which is demonstrable at the T-cell level. Our aim was to establish whether prenatal alcohol exposure alters the neuroendocrine and immune responses to chronic alcohol challenge in adult male and female offspring. Adult male rats placed on a liquid alcohol diet for 5 weeks had significantly decreased thymus weight, hypertrophied adrenals, and elevated plasma ACTH and corticosterone levels. Splenic lymphocyte Concanavalin A (Con A)-stimulated proliferation in the ethanol-treated rats was decreased compared to that in pair-fed controls. Thus, prolonged alcohol exposure activated the HPA axis and suppressed T-cell function. The effects of prenatal alcohol exposure, as a predispositional factor, on the HPA axis and on the T-cell functions of adult chronic alcohol-exposed rats were examined in the offspring of dams fed ethanol (FAE) or an isocaloric liquid (PF) diet during the last 2 weeks of gestation. The adult offspring of both sexes and prenatal treatment groups were then placed on an alcohol-containing liquid diet for 5 weeks. Fetal alcohol exposure decreased anterior pituitary proopiomelanocortin mRNA levels and increased glucocorticoid receptor (GR) mRNA levels in males and decreased GR mRNA levels in females. There were no differences in hypothalamic CRF mRNA and GR mRNA levels between the prenatal treatment groups. There was no significant difference in Con A-stimulated lymphocyte proliferation between FAE and PF males. However, FAE females showed Con A-stimulated lymphocyte proliferation significantly higher than those of all other groups, including pair-fed females. Prostaglandin E(2) (PGE(2)) suppressed lymphocyte proliferation to a lesser degree in FAE males than in any other group. Furthermore, T-cell response to Con A was enhanced by indomethacin, a prostaglandin biosynthesis inhibitor, in FAE males suggesting that increased prostaglandin synthesis may occur in FAE males after chronic alcohol exposure. Increased levels of endogenous PGE(2) could also be inferred from the enhanced levels of interleukin-2 receptor alpha (IL-2Ralpha) mRNA in activated lymphocytes of male but not of female FAE offspring compared to PF. In summary, the results of this study demonstrate that prenatal alcohol exposure leads to a specific HPA-related vulnerability in males to the deleterious effects of ethanol in adulthood. Although prenatal alcohol did not further aggravate the effects of chronic alcohol exposure on lymphocyte proliferation response to Con A in adult male offspring, altered T-cell responses could be unmasked.