ITN 1980 Radioimunoensaio da 17-alfa-hidroxiprogesterona no soro. Arq Bras Endocrinol Metab 24:1. 7. Biglieri EG, Wajchenberg BL, Malerbi DA, Okada H, ...
0021-972X/83/5705-1061 $02.00/0 Journal of Clinical Endocrinology and Metabolism Copyright © 1983 by The Endocrine Society
Vol. 57, No. 5 Printed in U.S.A.
DELORES P. PARDINI, CLAUDIO E. KATER,t JOSE GILBERTO H. VIEIRA, AND EDWARD G. BIGLIERI Department of Medicine, Division of Endocrinology, Escola Paulista de Medicina, Sao Paulo, Brazil; the Medical Service, San Francisco General Hospital Medical Center, and the Department of Medicine, University of California, San Francisco, San Francisco, California 94110
precursor to 21-hydroxylation, 17a-hydroxyprogesterone, the heterozygotes can now be characterized further by the impaired ACTH responses of mineralocorticoids distal to the block in the zona fasciculata; the ACTH-stimulated 17a-hydroxyprogesterone/18-hydroxydeoxycorticosterone ratio was greater than normal in 94% of the heterozygotes. A limitation of 21-hydroxylation may also exist in the zona glomerulosa. (J Clin Endocrinol Metab 57: 1061, 1983)
ABSTRACT. In 12 obligate heterozygotes for the simple virilizing form of congenital adrenal hyperplasia (21-hydroxylase deficiency), basal and ACTH-stimulated levels of aldosterone, corticosterone, deoxycorticosterone, 18-hydroxycorticosterone, and 18-hydroxydeoxycorticosterone were examined. The responses to ACTH were significantly impaired (P < 0.025-< 0.001) compared with those of normal subjects. In addition to the often exaggerated stimulation by ACTH of the immediate
D
EFICIENCY of 21-hydroxylase is an inherited disorder of steroid metabolism transmitted as an autosomal recessive trait. The genetic determinant is located in the short arm of chromosome no. 6, in close linkage with the HLA complex. The incidence of this type of congenital adrenal hyperplasia (CAH) ranges from 1:5000 to 1:15000 live births (in different geographic areas in the United States, Canada, and Europe) with a populational frequency of heterozygosity estimated at approximately 1:50 (1). Determination of HLA genotype as a marker for 21-hydroxylase deficiency has been accurate in predicting the heterozygous state within a family when at least one affected member has the manReceived September 27,1982. Address correspondence and requests for reprints to: Edward G. Biglieri, M.D., San Francisco General Hospital Medical Center, Room 320, Building 100, 1001 Potrero Avenue, San Francisco, California 94110. * This work was supported in part by USPHS Research Grant AM06415 from NIADDK. The studies in part were carried out in the General Clinical Research Center at San Francisco General Hospital Medical Center (RR-00083), with support by the Division of Research Resources, NIH. t Established investigator of CNPq (Conselho Nacional de Desenvolvimento Cientifico e Technologico, Brazil) under Contract 30.0449/ 81-CL.07.
ifestations of the deficiency (1). However, detection of heterozygotes among the general population requires biochemical identification. Obligate heterozygotes (parents) of patients with 21hydroxylase deficiency have a milder form of the enzymatic abnormality that is not manifested clinically (2). 17a-Hydroxyprogesterone (17a-OHP), the substrate for 21-hydroxylase in the biosynthetic pathway to cortisol, can be abnormally increased and/or excessively stimulated after exogenous adrenocortical stimulation (1-4). This steroid response has been used as a major marker for identifying heterozygotes (1, 4). We report herein that generalized impairment in the mineralocorticoid hormone responses to ACTH stimulation is an additional useful biochemical measurement that could identify the heterozygote in the general population. Subjects and Methods Seventeen heterozygote parents of affected persons with proved simple virilizing, nonsodium-losing form of 21-hydroxylase deficiency were studied at the Division of Endocrinology, Escola Paulista de Medicina (Sao Paulo, Brazil). Nine were women 32-45 yr of age (mean = 35) and 8 were men 35-51 yr of age (mean = 39). Consanguinity was established in one set
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Impaired Mineralocorticoid Hormone Responses to Adrenocorticotropin Stimulation: Additional Characterization of Heterozygosity for the 21Hydroxylase Deficiency Type of Congenital Adrenal Hyperplasia*
PARDINI ET AL.
1062
ACTH stimulation
test
ACTH stimulation was achieved by administration of an iv bolus of 25 Mg cosyntropin ( 1-24 ACTH, Cortrosyn, Organon,
West Orange, NJ) between 0800 and 0900 h while fasting and recumbent for approximately 1 h before the test. Blood samples for steroid determinations were obtained immediately before and 60 min after the injection. Steroid
determinations
Serum 1 7 a - 0 H P and cortisol were measured by RIA techniques developed at the Laboratory of Endocrinology, Escola Paulista de Medicina, according to previously published methods (6). Plasma aldosterone, deoxycorticosterone (DOC), corticosterone (B), 18-hydroxycorticosterone (18-OHB), and 18-hydroxydeoxycorticosterone (18-OHDOC) were determined in 12 heterozygotes (6 male and 6 female) and in 20 normal subjects. Specific RIA techniques for the individual steroids were used after extraction, solvent partitioning, derivatization, and chromatographic isolation (7). Corticosterone was measured after extraction and double paper chromatography by competitive protein-binding analysis (8). The ACTH-stimulated 1 7 a - 0 H P / 18-OHDOC ratio was calculated in 20 normal subjects and heterozygotes. Data were analyzed by Student's t test for independent means when comparing the stimulated (post-ACTH) values of each steroid among the two groups and the paired t test when comparing stimulated means with their control values (baseline) for the same group (9).
TABLE 1. Steroids of the 17a-deoxy pathway before and after administration of cosyntropin in heterozygotes for the 21-hydroxylase deficiency" Zona fasciculata (ng/dl)
Heterozygotes Male
Female
All (n = 12) Normal subjects (Male and female) (n = 20) Intergroup Comparisons Normal subjects us. heterozygotes
B
DOC
Group
C
ACTH 1140 1390 912 1980 2595 512 1545 2100 2260 1460 1395 747 1503" 183 29506
5.5 2.3 3.9 3.7 3.5 1.1 3.3 5.9 2.3 3.0 2.8 5.6 3.6 0.4 4.8
31.2 36.0 30.6 40.0 59.6 15.5 32.7 59.2 41.4 35.2 25.8 22.9 35.8* 3.8 81.5"
17.7 6.3 4.9 12.6 13.4 5.4 13.7 29.8 21.6 14.6 1.8 15.1 13.1 2.2 21.8
43.7 61.1 29.8 73.4 98.0 20.0 57.5 106.0 84.0 37.6 7.2 40.6 54.96 8.9 126.3"
9.7 4.9 6.7 9.9 5.2 8.8 9.8 11.6 8.5 9.5 7.4 9.1 8.4 0.6 7.9
9.8 8.9 3.6 7.2 10.0 8.4 9.0 15.9 16.4 12.4 9.2 13.1 10.3 1.0 20.1*
33
268
0.7
6.9
2.1
8.0
0.7
1.8
