Endokrinologie最新文献

The change of the pattern of clinical presentation of primary hyperparathyroidism in older patients is illustrated by a case history of a 61-year-old woman with multicystic kidney disease in whom a thiazide antihypertensive drug (clopamide) induced a very severe symptomatic hypercalcemia. Withdrawal of the drug was followed by a prolonged complete clinical remission, normocalcemia, normocalciuria, but consistently elevated parathormone levels. This "normocalcemic biochemical hyperparathyroidism" was complicated with hyperkalemia due to aldosterone suppression, a counterpart of the recently described association with hypokalemia due to primary hyperaldosteronism, necessitating further studies on the occurrence and significance of altered production of aldosterone in geriatric patients with primary hyperparathyroidism.

Studies were performed on lipid and corticosterone content in adrenal glands of intact male and female rats and on their relation to gonadectomy and gonadal hormone replacement. Concentration of total lipid, total cholesterol, phospholipid and glycerides is similar in adrenals of adult male and female rats, however their content, due to larger adrenals, is markedly higher in females. Orchiectomy has no effect on concentration of lipid classes studied while their content in adrenals increased. Testosterone replacement resulted in an increase in concentration of total lipid and phospholipid and has no effect on total cholesterol and glyceride concentration. Ovariectomy evoked an increase in total lipid and phospholipid concentration, has no effect on glycerides and lowered total cholesterol concentration in rat adrenals, while estradiol replacement diminished concentration of all classes of lipids studied. Adrenal corticosterone concentration is higher in female than male rat while no differences in BT-positive steroid were observed. Orchiectomy increased corticosterone concentration, after testosterone administration the value did not differ from control. Ovariectomy has no effect and estradiol increases corticosterone concentration in the gland. Performed studies suggest that testosterone increases the concentration of main classes of lipids and decreases the corticosterone concentration in the rat adrenal cortex while estradiol has an opposite effect.

The chlorpropamide alcohol flush test (CPAF) has been described as a dominantly inherited feature in NIDDM, particularly of young people (MODY-type). Validity and usefulness of the CPAF were analyzed in 40 MODY-patients recruiting from a population study (criteria acc. to Tattersall and Fajans, 1975), 59 first degree relatives (24 diabetics, 35 non-diabetics), 40 NIDDM of maturity onset, 40 IDDM, and 40 healthy controls. The CPAF (single challenge test, placebo control, subjective evaluation by questionnaire acc. to Köbberling, 1980) proved to be positive in only 8 MODY-patients and 5 of diabetic first-degree relatives. In comparison to NIDDM of maturity onset (40/8), IDDM (40/6) and healthy controls (40/2) the frequency of positive CPAF showed no significant differences. Between flushers and non-flushers within the MODY-group no relationship to vascular findings, metabolic and genetic data (including HLA-typing) could be found. It is concluded that the CPAF is a real but rather nonspecific phenomenon unsuitable as a genetic marker.

Inhibition constants describing competitive potency of thyroactive analogues and cortisol against labelled triiodothyronine (T3) in cytosol in human leukocytes were determined in the presence and the absence of theophylline by means of charcoal-dextran assay. L-triiodothyronine, L-thyroxine,L-thyroxamine,L-tetraiodothyroacetic acid, D-thyroxine and cortisol competed with T3 in binding sites of cytosolic proteins without theophylline addition. While theophylline addition increased the competitive potency (decreased the values of inhibition constants) of all thyroactive analogues, no such equivocal effect has been found in the case of cortisol.

STS 557, a new orally active progestin with antifertility properties has been tested for uterotrophic, antiuterotrophic, vaginotrophic, and antiovulatory effects. Further, maintenance of pregnancy in ovariectomized mice, influence on pregnancy in mice and rats, and conditioning of the immature rat uterus for decidual response were investigated. Both estrogenic and anti-estrogenic activities in mice and rats were found to be very low. STS 557 fails to maintain pregnancy in ovariectomized animals but does not interfere with pregnancy in intact mice if implantation already took place. Moreover, no effects have been found regarding the influence on the first ovulation in prepuberal rats. The biological profile of STS 557 in animals seems to make this compound suitable for use as a post-coital contraceptive.

The development and introduction of modern molecular biological methods was a prerequisite to the characterization of the insulin gene. The transfer of chemically synthesized genes for human insulin A and B chains as well as the naturally occurring rat insulin gene into bacteria opened possibilities to produce insulin in bacterial systems. Moreover, the structure of rat I and rat II insulin genes as well as human insulin gene were determined. Structural analysis of human insulin genes isolated from a human chromosomal gene library led to the identification of allelic variants of a single human insulin gene. The human insulin gene is located on the short arm of chromosome 11. The hypothesis that structurally abnormal insulin could play a role in the development of diabetes mellitus could be proved in clinical practice. Human insulin isolated from a diabetic patient showed an abnormality in the amino acid sequence and a decreased biological activity of the hormone. This finding demonstrates that in certain cases of diabetes mellitus the synthesis of structurally abnormal insulin due to a mutation in the insulin gene can be the cause for the development of relative insulin deficiency and hyperglycaemia.

Acceleration of ovulation in juvenile females by exposure to the male and injection of gonadotrophins was investigated. The male-induced ovulation in CBA/kw and outbred females was observed only after injection of PMSG. Exposure to the male and injection of HCG did not evoke this effect. Our results indicated that the presence of a male stimulates LH release from the pituitary of juvenile females. Pheromonal reaction of the females was affected by the age and body weight of the tested animals. Most sensitive were females of CBA/kw strain 21-day-old, outbred 21-day-old, 10.0-12.0 g and 24-day-old, 7.5-9.5 g.

In order to reveal the onset in ontogenesis of hypothalamic control of thyroid function 22-23-day-old fetuses of rabbits were encephalectomized. The concentrations of T3 and T4 in thyroid glands and blood serum were measured radioimmunologically on the 29th and 30th day of prenatal life. Significant differences of T3 and T4 concentrations are revealed only in thyroid glands of 30-day-old encephalectomized fetuses. Treatment of encephalectomized fetuses by TRH 30 min prior to fixation removed the effect of encephalectomy on hormone concentration and on thyroid structure. The represented data are considered as a proof of the establishment of hypothalamic cotrol of hormone synthesis in thyroid gland beginning from the 30th day of prenatal life. The regulation of hormone release from the gland is probably established at a later stage of maturation.

The development of diurnal rhythm of plasma and adrenal corticosterone levels was examined in rats overfed, standardfed and underfed during the suckling period (realised by adjustment of the number of suckling pups per litter to 4, 8, and 14). The first presence of circadian rhythm of plasma corticosterone was observed in 18-day-old overfed and standardfed rats, and slight delay in the manifestation of rhythm was noted in neonatally underfed animals (rhythm present in 21-day-old rats). The distinct circadian rhythm was present in 23- to 30-day-old rats. However in adult animals a significant diurnal rhythm of plasma and adrenal corticosterone content was noted in standardfed and underfed rats, whereas the variation of hormone levels was not significant in the neonatally overfed group. In young animals the peak of plasma corticosterone concentration occurred during the dark period while in adult animals it was shifted to the end of the light period. The values of amplitude of plasma corticosterone variation are increasing during the postnatal period. In weaned and adult rats the mesor values were found to be higher in neonatally underfed rats in comparison to the neonatally overfed group.

Thyroxine turnover and transport studies were done on 20 patients in the acute phase of viral hepatitis. No significant changes in T4 degradation rate (k), the T4 distribution volume (V), and the metabolic clearance rate (MCR) were found. A significant increase of T4 serum concentration and TBG capacity, and decrease of TBPA capacity were observed. A negative correlation between TBG and TBPA capacities was found. Significant interrelationships between TBG capacity and T4 serum levels as well as T4 turnover parameters were shown. The values of T4/TBG ratio were within normal range.