Endokrinologie最新文献

Binding to the androgen receptor of rat seminal vesicle was studied in vitro using cell-free extract or minced tissue. Relative binding affinities of 5 alpha-dihydrotestosterone (DHT), 5 alpha-dihydro-19-nortestosterone (DHN), nortestosterone and testosterone were estimated from their competition with [3H]-DHT for the binding sites. In contrast with the conflicting results obtained with cell-free systems incubated at 0-15 degrees C, studies performed with vesicular mince at 37 degrees C proved to be useful to demonstrate characteristic differences in binding affinity and to gain information about binding both to cytosol and nuclear receptors. Competition data were graphically analyzed, and after correction for steroid metabolism the following relative competition indices were obtained: DHT = 1.00; nortestosterone = 0.32-0.4; testosterone = 0.1-0.2; DHN = 0.12. However, binding to cytosolic and nuclear receptors did not differ significantly. It is concluded that testosterone and 19-nortestosterone (which are equally good substrates for 5 alpha-reductase) are converted in the seminal vesicles to metabolites, of which DHT exhibits an affinity to the androgen receptor nearly one order of magnitude higher than that of DHN. On the other hand, in skeletal muscles that are practically devoid of 5 alpha-reductase activity, the 3-fold higher affinity of nortestosterone to the receptor, expectedly, results in a myotropic activity that is superior to that of testosterone.

Thyroid function tests were obtained from 335 consecutive patients admitted to an intensive care unit. Twenty patients suffering from severe non-endocrine diseases (septicaemia, fulminant hepatic and renal failure, acute pancreatitis, polytrauma, cerebral haemorrhage) were found to have serum thyroxine levels in the hypothyroid range (less than 4 micrograms/dl). Serum concentrations of total thyroxine (2.3 +/- 0.2 micrograms/dl), triiodothyronine (0.23 +/- 0.03 ng/ml), and thyroxine binding globulin (15.1 +/- 1.3 micrograms/ml) were reduced, but were above normal for reverse triiodothyronine (0.43 +/- 0.06 ng/ml). Response of TSH secretion to iv TRH was found to be either normal, lowered or absent. Primary hypothyroidism was excluded, as no enhanced TSH response was observed in any case. Although decreased thyroxine levels may be due to increased thyroid hormone degradation it appears that associated impaired TSH responsiveness to TRH may result from illness-related inhibition of pituitary TSH release. Although the finding of decreased thyroid hormone levels is not rare in care patients, it represents an index of poor prognosis. Differentiation between this "low-T4 syndrome" and true hypothyroidism depends essentially on clinical symptoms and course of disease.

Based on a sensitive TSH-RIA (measuring-range 0.2-25 mU/l, 50%-intercept 2 mU/l, coefficients of between-assay-variation 5-10%) and on nearly 1200 cases, it is demonstrated that clinical results can be received by determination of basal serum-TSH alone. Values above 0.5 mU TSH/l indicate positive TRH-tests in a good correlation between increasing basal concentrations and pituitary TSH-reserve. TSH-levels below 0.3 mU/l proceed with negative TRH-tests. In selected healthy subjects, we found all TSH-values between 0.7 and nearly 5 mU/l (means = 1.99). In euthyroid goiters, TSH-levels are normally in the same range, but in nodular goiters, subnormal values were found accumulated. TSH-levels below 0.3 mU/l are helpful to discover non-suppressibility. Hormone-treatment of goiters is successful above all in case of high-normal pretherapeutic TSH-values. "Fine-tuning" of hormone-dosage (goiter-treatment, postoperative prophylaxis, suppression-therapy in thyroid carcinoma) as well as monitoring of thyrotoxicosis-treatment is recommended to be performed by means of basal TSH-determination. In pituitary disorders, thyroid hormone-treatment seems to be necessary only at TSH-levels below 0.5 mU/l. Combination of basal TSH and total T-3 is economical and describes nearly all functional situations in diagnosis and treatment of thyroid diseases.

Climbing perch thyroidal RNA content fluctuated in different phases of the reproductive cycle, highest at spawning (36.08 +/- 3.69 micrograms/mg tissue) and lowest at postspawning (6.88 +/- 0.76 microgram/mg tissue) whereas DNA remained unaltered. Treatment of intact perch with salmon gonadotropin (SG-G100) or ovine LH for 15 days significantly stimulated thyroidal RNA content. Stimulatory effect of SG-G100 was greater (p less than 0.001) than LH (p less than 0.005). FSH had no such effect. Gonadotropin (GtH) treatment could not alter thyroidal DNA. Ovarian steroids, 17 beta-estradiol (E2) and estrone (E1) remarkably elicited RNA content. Ovariectomy of perch caused striking depletion of RNA. Administration of GtH to ovariectomized perch had no effect on thyroid RNA but E1 and E2 supplementation resulted in significant stimulation in comparison to ovariectomized control. Findings indicate that GtH mediated its stimulatory effect on perch thyroidal RNA via the release of ovarian steroids.

Preliminary experiments showed that a course of 3 X 5000 IU Human Chorionic Gonadotropin (HCG) every alternate day in 5 patients with Klinefelter Syndrome caused increment in the circulating levels of testosterone, estradiol, and Sex Hormone Binding Globuline (SHBG). The levels of free testosterone, however, declined in 3 subjects and recorded no change in the remaining two. Estradiol/testosterone ratio on day 0 showed high correlation (r = 0.853) with augmented SHBG. It has been postulated that higher amount of SHBG is perhaps potentiating a reduction in the bioavailability of testosterone.

Radioimmunological methods have been employed for the simultaneous determination of dehydroepiandrosterone, androstenedione, testosterone, oestrogens (oestradiol + oestrone), progesterone, 17 alpha-hydroxyprogesterone and cortisol in human adipose tissue and peripheral blood to compare the hormone pool of adipose tissue with that in the general circulation. Extremely high steroid concentrations in the adipose tissue and hormone pool in the fat of obese subjects were observed. For adipose tissue/serum steroid ratios, the highest values were obtained for dehydroepiandrosterone and the lowest ones for cortisol. A preliminary study showed a great accumulation of steroids in adjacent adipose tissue of breast tumors. Striking differences were observed in the adipose tissue steroid concentrations between benign and malignant mammary tumors. The present findings revealed that blood hormone determinations may be insufficient to consider the steroid hormone availability in various endocrinopathies or steroid responsive tumors, especially when the endocrine state of extremely obese subjects is observed.

A 3 week training period in running restored the maximal swimming time of adrenalectomized rats to the level of intact untrained rats, but had no influence on the maximal running time and hepatic glycogen reserve. The cardiac hypertrophy and the augmentation of the Mg2+-activated ATPase activity of myocardium in adrenalectomized rats were more pronounced than in intact animals. It is concluded that the deficiency of adrenocortical hormones does not exclude all the adaptive alterations during training, although it makes the complete adaptation and normal increase of the working capacity impossible.