Alfred Tenore

Effect of Different Starting Doses of Levothyroxine on Growth and Intellectual Outcome at Four Years of Age in Congenital Hypothyroidism

To evaluate the effect of different initial levothyroxine (LT4) replacement doses on growth and intellectual outcome in patients with congenital hypothyroidism (CH) detected by neonatal screening program, the longitudinal growth and intelligence quotient (IQ) were assessed and compared at 4 years of age in 83 patients with CH. The patients were divided into three groups according to the initial LT4 dose used: (1) group 1 (n = 42) received the previously recommended dose of 6.0-8.0 microg/kg per day; (2) group 2 (n = 21) received a dose of 8.1-10.0 microg/kg per day; (3) Group 3 (n = 20) a dose of 10.1-15.0 microg/kg per day. The IQ, evaluated by the Wechsler Preschool and Primary Scale of Intelligence test at 4 years of age, was significantly higher in group 3 (IQ 98 +/- 9) compared to group 1 (IQ 88 +/- 13; p < 0.05) but not compared to group 2 (IQ 94 +/- 13). However, the IQs were below the normal range (< 85) in six patients from group 2 (28%), but in none of the patients from group 3 (p = 0.03). Patients from group 3, with severe CH at diagnosis, had an IQ (97 +/- 9) at 4 years of age, which was not different from that of patients from the same group with moderate CH at diagnosis (IQ 99 +/- 9). Similar results were also observed in patients from group 2 however, mean IQ scores in these patients (93 +/- 12) were several points lower than those observed in patients from group 3 (95 +/- 15). After the first month of treatment, optimal serum levels of thyroxine (T4) and free thyroxine (FT4) were achieved in all groups, however, only patients from group 3 were able to normalize thyrotropin (TSH) (group 1, 16.0 +/- 12.0; group 2, 9.2 +/- 10.0; and group 3, 2.4 +/- 3.3 mU/L; p < 0.0001). Twelve patients from group 2 treated with an initial LT4 dose above 9 microg/kg per day were able to normalize TSH levels within the first 3 months of life and this resulted in a better IQ (97 +/- 16) compared to the remaining patients from the same group (IQ 90 +/- 9). In the whole group of 83 patients the IQ at 4 years of age was positively correlated to both initial LT4 dosage (r = 0.27, p < 0.02) and FT4 concentrations after the first month of treatment (r = 0.29, p < 0.02), and negatively correlated to TSH concentrations after the first month of treatment (r = -0.27, p < 0.02). No significant differences were observed in height, weight, head circumference, and bone age maturation among the three groups of patients. No clinical signs or symptoms of overtreatment were observed during follow-up in patients receiving the higher LT4 dosage. Our results indicate that high LT4 starting doses rapidly normalize serum TSH concentrations resulting in an improvement of the IQ at 4 years of age, even in patients with severe CH at diagnosis. Growth and bone age maturation are not affected by such a high dose.

Long-Term Follow-Up of Diabetes in Two Patients With Thiamine-Responsive Megaloblastic Anemia Syndrome

OBJECTIVE To describe a 15-year follow-up of diabetes and to present data regarding pancreatic β-cell function in two adolescents affected by the thiamine-responsive megaloblastic anemia (TRMA) syndrome. CASE REPORTS The first patient (PMR) is a 17.5-year-old Italian girl who presented megaloblastic anemia at 7.5 months of age. At age 2.5 years, because of the presence of diabetes and sensorineural deafness, she was diagnosed with TRMA syndrome and started treatment with thiamine-HCl, followed very early by benzoyloxymethyl-thiamine (BOM-T). The second patient (PF) is a 16.8-year-old Italian boy born to consanguineous parents. Sensorineural deafness was diagnosed at age 1.5 years, while diabetes with ketoacidosis and megaloblastic anemia were diagnosed at age 3 years. Treatment with thiamine HCl was started immediately after diagnosis and changed to BOM-T 2 months later. Subsequent to the initiation of the vitamin, the two patients did not require insulin for ∼ 7 and 10 years, respectively. Puberty was determinant in deteriorating the metabolic control in these patients, leading to treatment with an oral hypoglycemic agent and finally to a reinstitution of insulin therapy. CONCLUSIONS The hormonal assessment in our patients (normal insulin response to oral glucose in childhood, preserved C-peptide secretion in case 2) and the good response to an oral hypoglycemic agent would indicate that the pancreatic disease may initiate as type 2 diabetes and may progress after several years to an insulin-requiring diabetes, as indicated by the exhaustion of the insulin secretory capacity.

Identification of heterozygote carriers of congenital adrenal hyperplasia by radioimmunoassay of serum 17-OH progesterone.

The response to administered adrenocorticotropin (ACTH, Cortrosyn) of 26 heterozygotes (parents of children with adrenal 21-hydroxylase deficiency) and of 14 controls are compared. The mean plasma levels of 4-pregnene-3, 20-dione-17, 21-diol (17-OH progesterone) were significantly greater in the heterozygotes 60 minutes (p less than 0.02) and 90 minutes (p less than 0.05) after stimulation with Cortrosyn than in controls. There is, however, considerable overlap. The results would indicate a partial enzyme deficiency in the parents of diseased subjects. There was no significant difference in the response of plasma cortisol.

Familial Hypopituitarism with Large Sella Turcica

We studied endocrine function in three siblings with short stature and enlargement of the sella turcica. Sellar volumes were 5.9, 3.7 and 4.0 standard deviations above age-specific means. Computed tomography or pneumoencephalography showed full sellae without suprasellar extension. Basal thyrotropin levels were low despite hypothyroidism and increments were less than 3 micromicron per milliliter after thyrotropin-releasing hormone injection. Stimulated growth hormone levels were less than 5 ng per milliliter, declining to less than 2 ng per milliliter after thyroxine treatment. Both thyroxine and growth hormone treatments were required for rapid growth. Impaired thyrotropin responses to thyrotropin-releasing hormone distinguish these patients from most cases of idiopathic or familial deficiency of thyrotropin and growth hormone. Persistent deficiency of growth hormone during thyroxine treatment indicates that the defects is not limited to thyrotropin structure or release. The findings are compatible with either familial neoplasia of the anterior pituitary or a regulatory defect promoting anterior pituitary-cell hyperplasia and inhibiting thyrotropin and growth hormone release.

Thyrotropin in Human Breast Milk

The thyrotropin (TSH) content of human breast milk was investigated, using both direct 125I-TSH radioimmunoassay and radioimmunoassay preceded by a partial purification step of elution from concanavalin A-Sepharose 4B. 15 samples of human milk between 1 and 13 weeks post-partum were found to contain 2.0 +/- (SD) 0.9 microU TSH/ml when assayed after Con A-extraction and adjusted for recovery by interpolation of a standard curve of Con A-extracted TSH standards. Recovery of 125I-hTSH tracer from both serum standards (58.6 +/- 5.5%; n = 10) and milk (53.6 +/- 6.7%; n = 15) were comparable. TSH levels obtained post-extraction were not significantly different from those that TSH is present in human breast milk in low concentrations, comparable to those normally found in the serum of euthyroid adults.

Hypothyroxinemia in Sick and Well Preterm Infants

From the University of Pennsylvania School of Medicine, Philadelphia, * and the School of Medicine, Catholic University of Puerto Rico.† Supported in part by National Institutes of Health Grants HD-00215; GM-20138 and RCDA 1 KO 4 00005. Correspondence to: John S. Parks, Associate Director, Division of Endocrinology, Children’s Hospital of Philadelphia, One Children’s Center, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104. Received for publication March 31, 1979 and accepted May 15, 1979. Editorial ~’~’c~~~c’ In the current era of screening for congenital hypothyroidism, preterm infants stand out as a population with a very high incidence of abnormal T~ results, but an incidence of true hypothyroidism, which is no different from that of term infants. The authors demonstrate that a majority of sick preterm infants have tow filter paper -1’4 levels. Ic1 contrast to the congenitally hypothyroid infants, they have high T3 uptakes, tow levels of thyroxine-binding globulin, normal TSH and normal CPK levels.

Serum 21-deoxycortisol and 17-hydroxypregnenolone in parents of patients with congenital adrenal hyperplasia.

The response of serum 21-deoxycortisol (21-DF), 17-hydroxypregnenolone (17-OHPE), 11-deoxycortisol and Cortisol to iv ACTH, was compared in 14 adult controls and 13 sets of parents of children with adrenal 21-hydroxylase deficiency. The baseline and post stimulation concentrations of hormones were similar in controls and parents, except for those of 21-DF, which were significantly greater in heterozygotes 30 min (p<0.005), 60 min (p<0.0025) and 90 min (p< 0.005) after stimulation with ACTH. When rates of increase were determined, those of 21-DF at 30, 60 and 90 min were significantly higher in the parents. Sixteen of the 26 parents (62%) had a rate of increase of 21-DF from 0 to 60 min greater than the mean plus two standard deviations of the control group. Using this same criteria, 11 of the 13 mothers (85%) of affected children could be identified as heterozygotes. The rate of increase of 21-DF from 0 to 60 min following ACTH provides a method for the detection of some heterozygote carriers of congenital adrenal hyperplasia and may be useful particularly in the identification of female carriers.

Sex differences in serum levels of N-acetyl-β-hexosaminidase in infancy: Correlation of enzyme activity with testosterone levels

Serum levels of N-acetyl-beta-hexosaminidase (HEX) (EC 3.2.1.30) activity in infants display a sexual dimorphism. Total HEX activity in males between 1 and 3 months of age is significantly elevated over female levels (male (M), 1535 +/- 300 nmol/60 min/ml; female (F), 1150 +/- 203, P < 0.0005), and the A (labile) isozyme constitutes a significantly lower proportion of the total activity present (M, 56.0 +/- 4.2, N = 24; F, 64.3 +/- 4.6, N = 21, P < 0.0005). These findings led us to investigate the relationship between testosterone concentration and HEX activity in serum. Samples from male (N = 36) and female (N = 33) infants between 1 and 6 months of age were included. In both sexes, a high degree of correlation (P < 0.0005) was observed between testosterone and total HEX (M, r = 0.71; F, r = 0.73), HEX A (M, r = 0.68; F, r = 0.56) and HEX B (M, r = 0.68; F, r = 0.72). An inverse relationship exists between testosterone levels and % A: M, r = -0.56; F, r = -0.38 (P < 0.0025 and 0.025, respectively). In contrast, no correlation between HEX levels and testosterone was evident in either male or female adults (r = 0.20 and 0.18, respectively). These data implicate testosterone in the regulation of HEX activity during the early months of human development.

Age- and sex-associated differences in the relationship of serum hexosaminidase and T4 levels in human neonates

N-Acetyl-β-glucosaminidase (HEX) activity (total, A and B) and serum thyroxine (T4) were determined in 22 cord serum samples, 240 serum samples from newborns up to 7 days of life, and 18 samples from infants one month of age, approximately equally divided by sex. Normal values for HEX activity in the neonatal period are given for both sexes. Cord serum values showed no significant sex differences in T4 levels, total HEX activity, and ratio of A:B isozymes. During the first week of life, highest levels of HEX activity (males: 1378 ± 337 U/ml; females: 1149 ± 178 U/ml; P < 0.01) occur between the first and second day, and coincide with peak serum T4 levels (males: 15.5 ± 2.9 μg/dl; females: 18.3 ± 3.3 μg/dl; P < 0.025). Although serum HEX activities in males are significantly elevated above female values throughout the first 7 days of life, no sex difference is seen in the (A:B) isozyme ratio (males = 51%:49%; females = 52%:48%). Sera from male infants at one month of age have a mean HEX level of 1734 ± 306 U/ml, which is significantly greater than that at one week of life (1231 ± 190 U/ml) (P < 0.0005). The ratio of A:B, however, remains constant (51%:49% at 1 week; 53%:47% at 1 month). Females show less-pronounced changes in total HEX values between one week (966 ± 155 U/ml) and one month (1174 ± 163 U/ml) (P < 0.005), but exhibit a marked alteration in the (A:B) isozyme ratio (52%:48% at 1 week to 61%:39% at 1 month, P < 0.0005). The percentage of HEX A in females at one month thus approaches prepubertal and adult values. The observed sex differences in HEX activity during the first month of life suggest that not only T4 but other sex-and/or developmentally related factors as well influence total HEX activity by specific regulation of its isozymes.

434 SEPARATION AND RADIOIMMUNOASSAY OF TRIIODOTHYRONINE (T3) IN HUMAN BREAST MILK

The purpose of this study was to identify and quantitate T3 in human breast milk (HBM), and to elucidate the relationship of this radioimmunoassayable material with organified 125I in Na125 I-injected rats. The presence of thyroid hormone, and particularly T3, in HBM has been poorly documented, and inconsistency in sample preparation and methods of quantitation have resulted in ambivalent data. Since thyroid hormones are routinely administered per-orally as corrective therapy for hypothyroidism, the presence of T3 in milk has obvious implications for thyroid regulation in the suckling newborn, as the infant will consume ∼ 800 ml/day by 4-6 wks. of age if exclusively breast-fed. Aliquots of either HBM or rat breast milk (RBM) were extracted with acidic ethanol (H+EtOH) after overnight digestion with pancreatin. Samples were eluted from an LH-20 column (Pharmacia) using an ethyl-acetate based solvent mixture. Iodotyrosine and-thyronine standards were run, both in their native form, and after extraction. While the bulk of absorbance (HBM)and organified 125 I (RBM) appears in the monoiodotyrosine (MIT) region of elution profiles, an absorbance peak in HBM in the region of the H+EtOH-extracted T3 standard was observed which corresponds to a radiolabelled peak in RBM. T3-RIA of this region revealed 625 ng/dl in HBM, equivalent to a dose of 5.0 μg/day (800 ml. day consumption in a 1 mo. old infant). We conclude from these data that HBM contains sufficient T3 to be of therapeutic value in amelioration of hypothyroidism in infants.