Evidence for the secretion of an antimineralocorticoid in congenital adrenal hyperplasia.

Plasma extracts from patients with congenital adrenal hyperplasia were found to contain substances that competed with aldosterone for mineralocorticoid receptor-binding sites in a rat kidney cytosol system. In normal subjects and patients with other disorders, the mineralocorticoid receptor-binding activity in such extracts could be entirely accounted for by the sum of the contributions of the steroids known to bind to the mineralocorticoid receptor. The secretion of these binding substances in patients with the C-21 hydroxylation defect was ACTH dependent. While these substances could be either mineralocorticoid agonists or antagonists, the latter is more likely. Production of mineralocorticoid antagonists would account for the compensatory hyperaldosteronism that occurs in the simple virilizing form, in which there is minimal impairment of aldosterone secretory reserve, and for the tendency to Addisonian crisis in patients with the salt-losing form, who have a more severe defect in aldosterone biosynthesis.

Abnormality of aldosterone and cortisol late pathways in glucocorticoid-remediable aldosteronism.

Patients with glucocorticoid-remediable aldosteronism (GRA) possess a chimeric gene resulting from fusion of the genes encoding steroid aldosterone synthase and 11 beta-hydroxylase. In the adrenal zona fasciculata, this may lead to ectopic expression under ACTH control of aldosterone synthase activity and increased formation of cortisol C18 oxidation products. We assessed mineralocorticoid and glucocorticoid pathways in three patients with GRA. Baseline plasma progesterone, 17 alpha-hydroxyprogesterone, corticosterone, and cortisol were normal in all patients, whereas 11-deoxycorticosterone, aldosterone, and 11-deoxycortisol were above normal. The ratios of both corticosterone/11-deoxycorticosterone and cortisol/11-deoxycortisol were abnormally low, and decreased further 60 min after administration of ACTH-(1-24) (250 micrograms) as an i.v. bolus. A low corticosterone/11-deoxycorticosterone ratio is consistent with an increased aldosterone synthase activity forming aldosterone by corticosterone. Similarly, a decreased cortisol/11-deoxycortisol ratio could reflect enhanced cortisol C18 oxidation. Our findings are in agreement with a hyperfunction of the 11 beta-hydroxylase/aldosterone synthase complex in the adrenal zona fasciculata of GRA induced by the new chimeric gene.

Contribution of the adrenal gland to the production of androstenedione and testosterone during the first two years of life.

Androstenedione and testosterone were measured in whole adrenal glands of 56 previously healthy boys who died suddenly between birth and 2 yr of age. In each adrenal gland, the concentration of androstenedione considerably exceeded that of testosterone. The highest concentrations were found during the first week of life (median, 295 ng/g; range, 98-320 ng/g). Thereafter, values decreased rapidly until the end of the first year of life (median, 10 ng/g; range, 4.4-22.7 ng/g). Adrenal testosterone concentrations averaged 15% of those of androstenedione in the same gland and similarly decreased until the end of the first year. The decrease of adrenal androgen concentrations paralleled the involution of the fetal adrenal zone. A close correlation existed between the concentration of androstenedione in adrenal tissue and plasma. However, no correlation existed between adrenal and plasma testosterone. When the adrenals and testes of the same infant were compared, there was 10 times more androstenedione in the adrenals than in the testes during the first 2 yr of life. The testes contained more testosterone than the adrenals only during the first 4 months. Thus, in infant boys the adrenals are the main source of androstenedione during the first 2 yr. After the sixth month of life, they also are the main source of testosterone.

Aldosterone receptors in different types of primary hyperaldosteronism.

The number of mineralocorticoid-binding sites on mononuclear leukocytes and plasma aldosterone (aldo) concentrations were measured in patients with different types of primary hyperaldosteronism. Patients with unilateral adenoma and patients with bilateral adrenal hyperplasia had a significantly lower (P less than 0.001) mean number of binding sites for aldo [144 +/- 36 (+/- SD; n = 6) and 140 +/- 28 sites/cell (n = 4), respectively] compared with normal subjects (292 +/- 110 sites/cell; n = 25). In four patients with dexamethasone-suppressible hyperaldosteronism, mineralocorticoid-binding sites in mononuclear leukocytes were normal (291 +/- 108 sites/cell). In all patients undergoing surgery for unilateral adenoma, the receptors normalized 3 months after the operation. In two patients the reduction in receptors persisted for a short time after surgery even though the plasma aldo level had already normalized. We conclude that mineralocorticoid excess produces down-regulation of mineralocorticoid receptors, which, in turn, might contribute to the genesis of the aldo escape phenomenon.

Testosterone and androstenedione concentrations in human testis and epididymis during the first two years of life.

Testosterone and androstenedione were measured in testicular and epididymal tissue of 37 previously healthy infants between 1 and 24 months of age who died suddenly. In half of the patients elevated plasma levels of cortisol and androstenedione suggested preterminal stress. Plasma testosterone levels, however, did not differ from those in healthy infants. Testicular testosterone concentrations were maximal in boys from 1-3 months of age (median, 36.6 ng/g; range, 7-380 ng/g) with peak values similar to those found in pubertal or even adult testes. Thereafter testicular testosterone concentrations decreased and after the age of 6 months all values were below 12.5 ng/g, which corresponds to the low normal range of older prepubertal boys. Plasma testosterone and testicular testosterone correlated significantly (P less than 0.001). On average the testicular concentrations were 36.4 times higher than the corresponding plasma concentrations. Testicular androstenedione was low but correlated significantly with testicular testosterone (P less than 0.001). Epididymal testosterone concentrations were surprisingly high (1-3 months: median, 10.3 ng/g; range, 4-42.7 ng/g) and averaged 30% of the testicular testosterone concentration. Thus, epididymal testosterone concentrations were significantly higher than the circulating plasma testosterone levels, indicating the capacity of the infant epididymis to accumulate androgens. These findings suggest that high local testosterone concentrations during early infancy are important not only for the testis itself but particularly for the developing epididymis.

Virilization without adrenal hyperplasia in 21-hydroxylase deficiency during fetal life.

The characteristic excess production of androgens in the cortisol 21-hydroxylase defect is generally considered to be secondary to ACTH stimulation of alternate pathways. Whenever a morphological examination of the adrenals has been possible in this disorder, adrenocortical hyperplasia was a constant finding. The availability of methods for the prenatal diagnosis of the 21-hydroxylase defect has made it possible to examine some of the manifestations of this disorder during fetal life. We studied a severely virilized 20-week-old aborted female fetus with the 21-hydroxylase defect whose adrenals were neither grossly enlarged nor microscopically hyperplastic. In a pregnancy at risk for congenital adrenal hyperplasia due to a 21-hydroxylase deficiency, amniocentesis was performed in the 18th week of gestation. The 21-hydroxylase defect was established by HLA typing and highly elevated levels of 17-hydroxyprogesterone, testosterone, and androstendione in amniotic fluid. After counselling, the parents, who already had a girl with the salt-wasting form of 21-hydroxylase deficiency, wished termination of the pregnancy. The aborted 20-week-old fetus was within the normal range for gestational age in weight and height. The external genitalia were ambiguous and extremely virilized, with an enlarged clitoris and fused labioscrotal folds. A urogenital sinus opened at the base of the clitoris. The internal organs were female, with a normal uterus and ovaries. Both adrenals were normal in size and weight for their gestational age. Histological examination of the adrenals revealed no abnormalities, and no hyperplasia was detectable. Thus, the adrenals in the 21-hydroxylase defect during fetal life secrete excessive amounts of androgens and cause virilization in the absence of adrenocortical hyperplasia.

The 21-hydroxylase activity in the glomerulosa and fasciculata of the adrenal cortex in congenital adrenal hyperplasia.

In the two clinical syndromes of congenital adrenal hyperplasia due to a 21-hydroxylation defect of adrenal steroidogenesis, the simple virilizing and the salt-wasting forms, the 21-hydroxylase activity was studied considering the zona fasciculata and the zona glomerulosa of the adrenal cortex as two separate glands under different regulation. To test this hypothesis, we stimulated adrenal steroidogenesis by ACTH infusion or dietary sodium restriction in eight patients with congenital adrenal hyperplasia (four patients with the simple virilizing form and four with the salt-wasting form of congenital adrenal hyperplasia) and in six normal children. Both the 17-hydroxy and 17-deoxy pathways of adrenocortical steroid biosynthesis were examined by measuring serum concentrations of 17-hydroxyprogesterone, cortisol, progesterone, deoxycorticosterone, corticosterone, and aldosterone and the excretion of free deoxycorticosterone, 18-hydroxydeoxycorticosterone, corticosterone, 18-hydroxycorticosterone, cortisol, and aldosterone. We considered the steroids 18-hydroxycorticosterone and aldosterone to be primarily of zona glomerulosa origin. These studies indicated that the zona fasciculata of both the salt-wasting and the simple virilizing forms is defective in 21-hydroxylation of 17-hydroxy and 17-deoxy steroids. The zona glomerulosa demonstrated deficient 21-hydroxylation only in the salt-wasting form, whereas in the simple virilizing form, the glomerulosa was spared this defect.

Impaired rapid mineralocorticoid action on free intracellular calcium in pseudohypoaldosteronism.

Earlier observations on impaired in vitro effects of aldosterone on lymphocytic sodium and potassium pointed to the involvement of a defective nongenomic rather than genomic effector in pseudohypoaldosteronism. In this study, we investigated nongenomic aldosterone action in five patients with pseudohypoaldosteronism with regard to a rapid increase of free intracellular calcium [Ca2+]i in cultured nasal epithelial cells, assumably reflecting calcium influx through calcium channels. Patients were defined by episodes of salt loss despite high plasma aldosterone and renin levels. Four unaffected members of the families and four independent subjects served as controls. Considering an aldosterone-induced increase of [Ca2+]i by at least 10 nm as positive response, only 12% of cells from patients were responsive compared with 25% in normal subjects (P < 0.05). In terms of absolute changes, mean increase of [Ca2+]i was 1.6 +/- 1.1 nm in the patients (range-1-4) and 9.5 +/- 2.7 nm (P < 0.025) in the controls (range 1-25). Basal [Ca2+]i was not different between both groups (167 +/- 5 vs. 169 +/- 8 nm, mean +/- SE). These findings show an impaired nongenomic mineralocorticoid effector in patients with pseudohypoaldosteronism, which is in line with a defective sodium channel as shown recently by molecular cloning, and also with the fact that the classical, genomic intracellular receptor is structurally normal in these patients.

Pseudohypoaldosteronism in eight families: different forms of inheritance are evidence for various genetic defects.

Pseudohypoaldosteronism is a rare hereditary disorder presenting in early infancy with renal salt loss leading to hyponatremia and hyperkalemia despite high levels of plasma aldosterone. The patients are insensitive to mineralocorticoids; however, sodium supplementation is able to correct electrolyte abnormalities. Absent or greatly diminished type I aldosterone receptors in peripheral mononuclear leucocytes have been recently demonstrated and explain the lack of response to mineralocorticoids. We have studied the mode of inheritance in eight families with a total of nine patients. There was evidence for an autosomal recessive form of inheritance in four families, while the other four families appeared to have an autosomal dominant mode of transmission. In three families the autosomal recessive form was characterized by normal receptor as well as hormone data in both parents, while in one family receptor levels in both parents were greatly reduced, but hormone levels were normal. In the four families with an autosomal dominant mode of transmission there was always one parent with reduced receptor binding in peripheral mononuclear leucocytes and elevated serum hormone levels. These parents were entirely asymptomatic. In an extended family we were able to study an aunt and her newborn daughter, who were both also biochemically affected but clinically asymptomatic. It, therefore, appears that this dual pattern of genetic transmission may indicate differing genetic defects which cause the same clinical picture of pseudohypoaldosteronism.

Exclusion of the locus for autosomal recessive pseudohypoaldosteronism type 1 from the mineralocorticoid receptor gene region on human chromosome 4q by linkage analysis.

Pseudohypoaldosteronism type 1 (PHA1) is an uncommon inherited disorder characterized by salt-wasting in infancy arising from target organ unresponsiveness to mineralocorticoids. Clinical expression of the disease varies from severely affected infants who may die to apparently asymptomatic individuals. Inheritance is Mendelian and may be either autosomal dominant or autosomal recessive. A defect in the mineralocorticoid receptor has been implicated as a likely cause of PHA1. The gene for human mineralocorticoid receptor (MLR) has been cloned and physically mapped to human chromosome 4q31.1-31.2. The etiological role of MLR in autosomal recessive PHA1 was investigated by performing linkage analysis between PHA1 and three simple sequence length polymorphisms (D4S192, D4S1548, and D4S413) on chromosome 4q in 10 consanguineous families. Linkage analysis was carried out assuming autosomal recessive inheritance with full penetrance and zero phenocopy rate using the MLINK program for two-point analysis and the HOMOZ program for multipoint analysis. Lod scores of less than -2 were obtained over the whole region from D4S192 to D4S413 encompassing MLR. This provdes evidence against MLR as the site of mutations causing PHA1 in the majority of autosomal recessive families.

Pseudohypoaldosteronism: mutation found, problem solved?

The term 'pseudohypoaldosteronism' includes at least three distinct clinical syndromes, classified as type I, II and III, which differ in their clinical and biochemical findings but have in common the symptoms of mineralocorticoid resistance. The finding of a defect in the recently cloned epithelial sodium channel (ENaC) in a subgroup of familial pseudohypoaldosteronism type I has changed our understanding not only of the pathophysiology of these disorders but also the physiology of renal salt and water homeostasis. In this review the various clinical, biochemical and genetic findings in the different forms of pseudohypoaldosteronism will be discussed with the aim of identifying the underlying differences and similarities. The direction of further genetic investigations will depend at least in large part on further clinical classification of patients and families.

Inactivating mutations of the mineralocorticoid receptor in Type I pseudohypoaldosteronism.

Type I pseudohypoaldosteronism (PHA1) is a rare form of mineralocorticoid resistance characterized by neonatal renal salt wasting and failure to thrive. Typical biochemical features include high levels of plasma aldosterone and renin, hyponatremia and hyperkalemia. Different mutations of the human mineralocorticoid receptor (hMR) gene have been identified in subjects affected by the autosomal dominant or sporadic form of the disease. Our laboratory has investigated a large number of subjects with familial and sporadic PHA1. Several different mutations have been detected, which are localized in different coding exons of the hMR gene. These mutations either create truncated proteins, either affect specific amino acids involved in receptor function. In this paper, we review hMR mutations described to date in PHA1 and their functional characterization. We discuss the absence of mutations in some kindreds and the role of precise phenotypic and biological examination of patients to allow for identification of other genes potentially involved in the disease.

Evidence for a critical region for penoscrotal inversion, hypospadias, and imperforate anus within chromosomal region 13q32.2q34.

Two unrelated patients with small distal deletions of the long arm of chromosome 13 are described, with shawl scrotum and penoscrotal transposition, penoscrotal hypospadias, a reduced perineum, and anal atresia. The patients have small deletions of 13(q32.2qter) and 13(q32q34), respectively. This report and the literature present evidence for one or possibly more gene(s) within region 13q32.2q34 which regulate the development of the ano-genital structures. The clinical spectrum includes bifid or shawl scrotum, hypospadias, biseptate uterus, malplaced and imperforate anus, and common cloaca.

Immunofluorescence of mineralocorticoid receptors in peripheral lymphocytes: presence of receptor-like activity in patients with the autosomal dominant form of pseudohypoaldosteronism, and its absence in the recessive form.

Pseudohypoaldosteronism is a syndrome characterized by salt wasting and a failure to thrive due to the resistance towards the action of aldosterone. Aldosterone levels and plasma renin activity are extremely elevated and aldosterone binding sites in peripheral mononuclear leukocytes have regularly shown to be reduced or absent. Sporadic as well as familial cases have been identified and an autosomal dominant as well as an autosomal recessive mode of inheritance has been described. A defect in the aldosterone receptor has been postulated, however, molecular genetic analysis in selected patients has not revealed a mutation in the sequence of the coding region of the cDNA of the mineralocorticoid receptor gene. In the present study we have used a fluorescence-labeled antibody to detect possible receptor expression in monocytes from patients with various clinical forms of pseudohypoaldosteronism. Patients with the sporadic as well as with the autosomal dominant form were clearly immunopositive despite being negative in terms of aldosterone receptor binding. In contrast in two patients with the autosomal recessive form there was no detectable receptor protein, consistent with the results obtained in the aldosterone binding studies. These results suggest that the pathogenesis of pseudohypoaldosteronism is heterogeneous not only regarding the mode of inheritance but also in terms of receptor binding. Thus, in a subgroup of patients the inability of the receptor to bind ligand may be due to a defect involving other, probably cellular factors rather than a deficiency or a defect in the mineralocorticoid receptor system itself.

Partnership and sexuality in adult female patients with congenital adrenal hyperplasia. First results of a cross-sectional quality-of-life evaluation.

In congenital adrenal hyperplasia affected female patients are born with ambiguous genitalia caused by prenatally elevated circulating androgens from the defective adrenal glands. Surgical correction and life-long medication is needed to enable a normal female life. In contrast to androgen-related behaviour little information is available regarding the psychosocial consequences of genital malformations and lifetime medical treatment on the life of female patients. We report the results regarding partnership and sexuality of a comprehensive quality-of-life evaluation of female patients with congenital adrenal hyperplasia. While there was no significant difference in the first overall evaluation between the various clinical forms of congenital adrenal hyperplasia, patients differed significantly from healthy controls in regard to partnership and sexuality. However, overall analysis suggested, that the patients were able to adjust well to their condition and were able to lead a normal life. Further longitudinal research is needed to more clearly identify problem areas and to improve medical and psychological treatment.

Androgen binding sites in peripheral human mononuclear leukocytes of healthy males and females.

Androgen binding sites have been identified in circulating human mononuclear leukocytes of healthy donors of both sexes. Cells were separated from blood samples on a Ficoll gradient and incubated with different concentrations of [3H]testosterone in the presence or absence of a 400-fold excess of unlabelled testosterone. Binding data were derived from Scatchard analysis. The binding sites fulfil the required criteria for specific steroid binding sites however differ somewhat from the classic androgen receptors from genital skin fibroblast: in fertile adult males (n = 20) the binding sites showed (1) a high affinity for testosterone (1.32 +/- 0.49 nM; mean +/- SD), (2) a saturable capacity (184 +/- 52 binding sites per cell; mean +/- SD), and (3) a characteristic competitive binding profile for other steroid hormones (relative binding affinities: testosterone = dihydrotestosterone > 17 beta-estradiol > progesterone, whereas aldosterone, 17-hydroxy-progesterone and cortisol did not compete appreciably). Furthermore the number of binding sites determined using [3H]dihydrotestosterone, [3H]RU-1881, or [3H]testosterone were comparable. This raises the possibility that androgen receptors in peripheral mononuclear leukocytes differ from those in genital skin fibroblasts. There was no apparent correlation between serum testosterone concentrations and androgen binding sites. In fertile women remarkable changes in androgen binding sites were seen in the course of the menstrual cycle, with a significant increase in the immediate preovulatory period. The presence of androgen receptors in peripheral mononuclear leukocytes provides for the first time the experimental basis for an hypothesis of direct, receptor-mediated effects of androgens on mature immunocompetent cells. The immunological implications of these results are discussed.

Pseudohypoaldosteronism and mineralocorticoid receptor abnormalities.

Pseudohypoaldosteronism is a rare inherited disease characterized by renal salt loss, hyperkalemia and metabolic acidosis despite highly elevated aldosterone values. We previously reported absent or reduced numbers of mineralocorticoid receptors in mononuclear leukocytes and defective effector mechanism as shown by no response in vitro to the incubation of aldosterone in terms of intracellular electrolyte content. We have studied the inheritance of this disorder in ten families and found two different kinds of inheritance: autosomal recessive--often in interrelated families--and autosomal dominant in unrelated families. Parallel studies in the families with the autosomal dominant form of inheritance demonstrated in addition that the effector mechanism of aldosterone is impaired in vitro both in the affected patients and in the carrier relatives characterized by a low number of mineralocorticoid receptors.

Familial pseudohypoaldosteronism: a review on the heterogeneity of the syndrome.

Pseudohypoaldosteronism is thought to be a rare salt-losing disorder, caused by resistance to the action of aldosterone. Defective aldosterone receptor binding is present in familial as well as sporadic cases and it has been suggested that the pathogenesis is due to a defect in the aldosterone receptor system. To date, however, molecular genetic analysis has been unable to identify a mutation in the aldosterone receptor gene itself. We have reviewed the findings in patients with pseudohypoaldosteronism, for clues which might enable us to identify the underlying pathogenesis. Although aldosterone receptor binding is regularly decreased or absent in monocytes of patients with pseudohypoaldosteronism, in some patients receptor protein can be detected with a fluorescence-labeled antibody. Receptor protein was detected in patients from familial autosomal dominant families and in sporadic cases, but was undetectable in two patients with the familial recessive form. To further elucidate the pattern of inheritance we studied the response of the renin-angiotensin-aldosterone system to the stimulation by sodium depletion in the familial autosomal dominant form and in two families with sporadic cases. In both "sporadic" families investigated, one parent and one sibling had an exaggerated response of renin and aldosterone to sodium depletion indicating a defect of sodium conservation apparent only during stress, leading to reclassification as familial cases. No additional family member in the "classical" autosomal dominant families responded abnormally to sodium depletion. These findings indicate that pseudohypoaldosteronism is unusually heterogeneous in its clinical, biochemical, and genetic presentations and findings and suggest that its pathogenesis is heterogeneous as well.

Pseudohypoaldosteronism: evaluation of type I receptors by radioreceptor assay and by antireceptor antibodies.

We have previously demonstrated a deficiency of mineralocorticoid receptors in pseudohypoaldosteronism, by radioreceptorassay. We now report findings with an antireceptor antibody derived from the immunogenic region of the receptor. Lymphocytes from normal controls and from two cases of pseudohypoaldosteronism previously shown to lack receptor binding were tested. After the plasma membrane of lymphocytes was permeabilized with methanol the cells were incubated with a 1:200 dilution of antibody followed by fluorescent antirabbit immunoglobulin mouse serum. After washing fluorescence was detected by microscopy and cytofluorimetry in both controls and patients with pseudohypoaldosteronism. Recent studies on mineralocorticoid receptor cDNA in pseudohypoaldosteronism have not established a mutation in the sequence. We thus suggest that the pathogenesis of pseudohypoaldosteronism is not related to an abnormality of the receptor but rather due to intracellular factor(s) which can block the binding of aldosterone to its receptor.

True hermaphroditism in an XY individual due to a familial point mutation of the SRY gene.

A number of genes are known to control the development of the testis but the transcription factor SRY encoded on the Y-chromosome is considered to play the major role in initiating the first step in determining testicular differentiation. Mutations in this gene usually result in gonadal dysgenesis, but it is interesting to note that at least three of these mutations have been found to be familial. Furthermore, fewer than 10% of true hermaphrodites carry an XY karyotype, and so far only two patients have been documented to carry a mutation in the SRY gene. We have identified a familial mutation in the SRY gene involving a previously described locus. The index patient was born with severely ambiguous genitalia and on histological examination the gonads revealed true hermaphroditism, containing ovarian as well as testicular tissue. The father, his three brothers, and his first-born son carry the identical mutation. The severely feminized XY individual was diagnosed shortly after birth, gonadectomized and raised as female. SRY was determined by PCR and subsequently sequenced using cycle sequencing. A previously published point mutation was identified at nucleotide position 680 resulting in a non-conservative exchange of the amino acid iso-leucine at position 90 into methionine. This position represents a mutational 'hot spot', which seems to retain a certain amount of protein activity, enabling normal male development in some individuals. The patient is the third one reported in whom a mutation in the SRY gene results in ovarian-like development. Since ovarian development in XY individuals is extremely rare, its mechanism is of great interest. Further studies in this family might allow the identification of factors initiating and stimulating ovarian development. How far these infantile ovaries would have developed normally, however, is merely speculative.