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Biomedical subjects

B Noelpp

Publications and source records attributed to B Noelpp.

10 recordsLinked to original sources
PubMed1983

The relationship of serum thyrotropin (TSH) to the thyroid hormones after oral TSH-releasing hormone in patients with preclinical hypothyroidism.

Serum thyroid hormone and TSH concentrations were measured before and after oral TRH (40 mg) administration in 46 women with preclinical hypothyroidism. Preclinical hypothyroidism was defined as serum T4 in the normal range, a normal or elevated basal serum TSH, and an exaggerated serum TSH response to TRH, in the absence of clinical manifestations of hypothyroidism. The results were compared to those in 22 normal women of the same age and body mass index. Overall, the patients had significantly lower mean values for basal T4 [total T4, free T4 index (FT4 index), and free T4] but not for T3; all indices of T4 were lower in those with an elevated basal TSH, but only the FT4 was lower in patients who had normal basal TSH levels and exaggerated TSH responses to TRH. Thyroid reserve, or the increase in serum thyroid hormones after TRH (delta T4, delta FT4, and delta T3) showed an inverse correlation with basal TSH (for delta T4, r = -0.518 and P less than 0.001; for delta FT4, r = -0.442 and P less than 0.05; for delta T3, r = -0.645 and P less than 0.001). Thyroid reserve was lower than normal in those with elevated basal TSH levels, but was normal in those with exaggerated TSH responses to TRH who had normal basal TSH levels. Thus, an elevated basal TSH level, even with basal serum T4 and T3 levels in the normal range, indicates deficient thyroid reserve.

Administration, Oral↗
PubMed1981

[Thyroid hormones and thyroid reserve in preclinical hypothyroidism].

Preclinical hypothyroidism (i.e. basal thyroxine within the normal laboratory range, basal TSH normal or elevated and exaggerated TSH response to TRH) is a biochemical constellation of uncertain clinical relevance. The oral TRH test with simultaneous measurements of TSH and thyroid hormones before and 3 h after 40 mg TRH provides information about both pituitary and thyroid reserve. In a group of female patients with preclinical hypothyroidism, basal thyroxine but not triiodothyronine was found to be clearly diminished compared with a group of healthy female controls, indicating a slight thyroid hormone deficiency. Furthermore, a progressively reduced thyroid reserve of T4 and especially of T3 was seen to be closely related to elevation of basal TSH as an expression of thyroid cell insufficiency. These data emphasize the clinical importance of TSH elevation despite normal thyroxine levels as a better individual sign of impending primary hypothyroidism.

Female↗
PubMed1981

[Lipid changes as a possible risk factor in preclinical hypothyroidism. Preliminary report].

In a prospective study the lipids have been investigated in patients with preclinical hypothyroidism (normal values for thyroxine and free thyroxine index but exaggerated response to oral TRH and normal or elevated basal TSH). This group was compared with euthyroid normal subjects and patients with overt hypothyroidism. Cholesterol and triglycerides were normal in patients with preclinical hypothyroidism, in contrast to the increased levels in overt hypothyroidism. HDL cholesterol showed no difference in either group. Lipid electrophoresis on agarose with densitometric analysis revealed elevation of low density lipoproteins (LDL) and diminution of high density lipoproteins (HDL) in both groups of hypothyroid patients. The changes in LDL and HDL are both known coronary risk factors and could explain the reported prevalence of coronary disease in the early stages of thyroid failure. These preliminary findings need further confirmation.

Cholesterol↗
PubMed1979

The short metyrapone test: comparison of the plasma ACTH response to metyrapone and insulin-induced hypoglycaemia.

Plasma ACTH levels in response to metyrapone and insulin hypoglycaemia were compared in subjects with normal pituitary-adrenal function. After a single dose of 2 g of metyrapone given with a snack at midnight, the ACTH level was 468 ng/l +/- 66 )SEM) at 07.30 h the next morning (mean increment approximately nine fold over normal morning values). After insulin-hypoglycaemia the peak ACTH level was 369 ng/l +/- 31 (SEM). Peak ACTH levels greater than 200 ng/l were achieved in twenty of twenty-one (95%) subjects after metyrapone and twenty of twenty-four (83%) after insulin. No major side effects were noted after metyrapone. It is concluded that the short single-dose metyrapone test produces at least as strong and consistent a stimulus to ACTH release as the standard insulin-hypoglycaemia test in normal subjects. A direct assay of ACTH avoids misinterpretations which are inherent in a judgement based on compound S increase only. The short test has significant practical advantages over the classical metyrapone test, and provides a convenient and sensitive method of assessing the negative feedback ACTH control mechanism. It may be particularly useful in detecting minor degrees of pituitary suppression. The value of this test in clinical practice for the investigation of patients with hypothalamic-pituitary diseases in comparison to the classical tests of ACTH stimulation has yet to be demonstrated.

Adolescent↗
PubMed1977

[Standardization of a new thyroid gland suppression test by means of 3000 microgram L-thyroxine].

The suppressibility of the TSH-thyroid axis one week after a single dose of 3000 microgram L-thyroxine was studied in 21 euthyroid subjects. In all cases the normal thyroid function was proven by euthyroid values for thyroxine (T4), free thyroxine index (FT4-I), triiodothyronine (T3), radioiodine uptake, PBI-131, a normal scintiscan and by a physiologic TSH response to thyrotropin-releasing hormone (TRH). Compared to the baseline values the mean suppression of radioiodine uptake at 2,24 and 48 h was 61.8% (+/- 32.9), 62.0% (+/- 15.3) and 62.1% (+/- 13.4) respectively. Because of the large variation at 2 h this value can be disregarded. If the 24 h value shows a clear suppression over 50%, no further measurement is necessary. Mean serum levels of thyroxine and free T4-index rose from 8.2 +/- 1.0 to 13.0 +/- 2.1 microgram/100 ml and from 7.7 +/- 1.9 to 15.1 +/- 3.4 respectively on the third day, to the upper limits for normal controls. Triiodothyronine increased from 1.69 +/- 0.42 to 2.08 +/- 0.38 ng/ml and remained definitely below the level of 2.60 ng/ml observed in overt thyrotoxicosis. In single subjects T4, FT4-I or T3 achieved slightly hyperthyroid levels. In view of the effectiveness of a single dose of 3000 microgram T4 with good suppression of radioiodine uptake and TSH production after stimulation with TRH without noticeable side effects, the classical T3 suppression test should be abandoned and replaced by this test, which latter can be used for the same diagnostic and therapeutic purposes.

Humans↗