Endokrinologie最新文献

The effect of alpha-melanocyte-stimulating hormone (alpha-MSH) on the fetal adrenal cortex in rat was studied in vivo and in vitro. In vivo, an injection of alpha-MSH stimulated the adrenal cortex slightly. Treatment of the adrenal cortex with alpha-MSH in organ culture caused hyperfunctional change in the innermost layer of the cortex, the detection of which was done by electron microscope. This treatment caused at the same time an increase in corticosterone in the culture medium. Furthermore, comparison was made between alpha-MSH and ACTH with respect to their effect on the fetal adrenal cortex.

In the present study the attempt was made to evaluate the functional state of the adrenal cortex after space flight by means of the urinary corticosteroid content. The urine collected over 24 hours was analysed. The following parameters were determined: Total 17-hydroxycorticosteroids (17-OHCS), their free forms, glucuronides and sulphates; cortisol (F), cortisone (E), corticosterone (B), 11-desoxycortisol (S), 11-dehydrocorticosterone (A), tetrahydrocortisol (THF), tetrahydrocortisone (THE), tetrahydrocorticosterone (THB), tetrahydro-11-desoxycortisol (THS), and aldosterone. In order to characterize the activity of the 11-hydroxylase the quotient of THS + S/THF + F + THE + E was formed. The activity of the 17-hydroxylase was determined indirectly by the quotient of THF + THE + THS + F + E + S/THB + B + A = 17-OHCS/17-DOHCS. The expected distinct increase of the 17-OHCS after the space flight failed to appear. This finding may be due to an adrenocortical dysfunction. In the space ship commander the quotients indicate a reduced 11- and 17-hydroxylation during the process of synthesis of the glucocorticoids. In the flight engineer they give evidence of an unchanged biosynthesis except on the day of landing. A hitherto not fully intensified substance ("white spot") was found in the chromatogram of the space ship commander on the first and second day after the flight. Moreover, the investigations show that the reaction of the adrenal cortex after space flights exhibits a number of individual characteristics.

With a view to impart selective uptake of estrogen by the target tissues of rat, liposomes in which (6,7-3H) oestradiol-17 beta constituted a part of lipid bilayer were used as carriers of the hormone. The distribution and retention of the radioactivity was determined in blood plasma, uterus, liver, kidney, spleen and leg muscle of ovariectomized rat at different time intervals up to 72 hr following a single intravenous injection of free oestradiol (1.61 muCi) or an equivalent amount of liposomal-oestradiol. When free oestradiol was administered, uterus showed peak amount of radioactivity between 30 min to 2 hr and remained high up to 6 hr. In the other tissues examined, maximum amount of radioactivity was seen at 15 min followed by a marked fall at 30 min and also at other subsequent intervals. The pattern of uptake and retention of radioactivity after administration of liposomal-oestradiol was not much different from that of free oestradiol between 1 and 6 hr. A moderate increase in the amount of radioactivity in the nongenital tissues at 24 hr was the only difference noticed with liposomal-oestradiol. It is concluded that targeting of oestradiol preferentially to the uterus could not be achieved through liposomal delivery system.

The present study was conducted in 12 healthy volunteers to determine the effect of porcine insulin (0.15 U/kg i.v.) on a number of different metabolic and hormonal parameters measured simultaneously. The nadir of blood glucose (19.0 +/- 2.7 ng/100 ml) is detected 30 min following insulin application, paralleled by suppressed levels of FFA and beta-hydroxybutyrate. The lowest level of potassium (3.39 +/- 0.09 mval/l) is observed 45 min following insulin application. The hormones of counterregulation show an uniform pattern of response. Peak levels of norepinephrine (228.9 +/- 36.0 ng/l) and epinephrine (720.6 +/- 125.6 ng/l) are observed at 30 and 45 min, those of cAMP (33.4 +/- 2.5 pmol/ml), glucagon (0.209 +/- 0.024 ng/ml), ACTH (166.0 +/- 40.1 ng/ml), and prolactin (28.1 +/- 7.8 ng/ml) at 45 min and finally those of cortisol (26.1 +/- 3.3 micrograms/100 ml) and growth hormone (21.6 +/- 3.1 ng/ml) at 60 min following insulin injection. As the blood glucose level is already rising after 30 min it is concluded that the catecholamines and glucagon play a major part in the restitution of normal blood glucose levels. At the end of the test, blood glucose and hormone levels have almost normalized, but FFA and beta-hydroxybutyrate levels are doubled and almost triplicated as compared to the starting point levels.

In 534 unselected schoolchildren aged 6-14 yr from the greater Athens area the size of the thyroid gland was assessed by palpation, and information was obtained on sex, age, height, weight, skinfold thickness, socioeconomic class, eye colour and urinary iodine excretion. The results were analysed by discriminant analysis. Altogether 14% of these children had a thyroid enlargement (7% had a definite goitre and another 7% a smaller enlargement). The set of variables studied were significantly discriminatory (Wilk's lambda 0.926, p approximately equal to 0.004). Most of the discrimination was accounted for by height (positive association, b coefficient 0.0114, SE 0.0029, t = 3.95) and weight (negative association, b coefficient 0.0107, SE 0.0030, t = 3.61). No other parameter, including iodine excretion, showed a significant difference between goitrous and nongoitrous. It is concluded that the only genuine difference is that goitrous are heavier for a given height or shorter for a given weight, i.e. more obese. The reason for which obesity protects from sporadic nontoxic goitre is not entirely clear, but probably both nutritional and genetic factors are involved.

In tests on a thymocyte culture from adrenalectomized rats, we studied the effect of fifty synthetized transformed steroid compounds, containing delta 4-keto-or delta 5-3-oxygroups in ring A, oxygen containing substituents in ring D, and a superstructured 20-keto side chain, on the glucocorticoid and antiglucocorticoid effects and steroid-receptor interaction. Ten compounds (conc. 10(-6)M) competed with 3H-triamcinolone acetonide for binding the thymocytes over the cytosol glucocorticoid receptor. Steroid compounds containing a delta 4-3-ketogroup (conc. 10(-6)M) suppress inclusion of 3H-uridine in thymocyte RNA more than compounds containing a delta 5-3-oxygroup. An antiglucocorticoid effect on thymocyte function is produced by 16,17 alpha-isopropylidendioxy-21-methylidene-pregn-5-en-3 beta-ol-20-one, 16,17 alpha-isopropylidendioxy-pregn-5-en-3 beta-ol-20-one and 16,17 alpha-isopropylidendioxy-21 a-methyl-21, [21a]-epoxy-21-homopregn-4-en-3, 20-dione at concentration of 10(-6) M.

In a previous experiment histamine, a phagocytosis promoting hormone of vertebrates, was employed to enhance the phagocytosis of Tetrahymena to demonstrate the possibility of receptor amplification by a short treatment. A long-term treatment with histamine also stimulated the phagocytotic activity of the Tetrahymena, and the stimulatory effect persisted for some time after return to plain medium. In this experiment the function was observed and the hormone binding of cells was not taken into consideration. In the present study evidence was obtained that a lasting first exposure to histamine durably enhanced the histamine binding capacity of the unicellular. This indicates a parallelism of alterations in the histamine binding capacity and phagocytotic function of Tetrahymena. It was also shown that lasting re-exposure to histamine depressed rather than enhanced the histamine binding.

Diestrous female rats were bilaterally lesioned in the perisuprachiasmatic region (peri-SCN region) or in the medial preoptic area (MPOA) and ovariectomized immediately after lesioning. Blood was collected at one hour before and at 4.24 and 48 h after surgery. Radioimmunological determination of the serum gonadotropin concentrations revealed that lesioning of the peri-SCN region enhanced significantly the castration-induced increase of FSH and LH secretion at 4 and 24 h, whereas MPOA lesions did not influence the serum hormone levels as compared to the sham-lesioned controls. The findings suggest that the peri-SCN region, but not the MPOA may be involved in the control of the increase of gonadotropin secretion following ovariectomy in rats.

Chemically pure or highly purified proteins have been analysed for their specific uridine binding. The peptides generally have two well distinguishable binding sites for uridine regarding their Kd and Bmax values. Uracil competed for the uridine binding sites with uridine, whereas adenine, corticosterone and testosterone did not. The adenine and the sexual steroids augmented the number of maximal binding sites in many cases. The number of specific binding sites varied from 1 to 61 per peptide (Kd: 1.1--51.7 X 10(-10) M).

The effects of insulin, cortisol, prolactin, 3,3',5-triiodo-L-thyronine (L-T3) and progesterone on the synthesis of total protein and casein in mammary explants from pregnant goats were studied. In the absence of hormones and in the presence of insulin plus cortisol the rate of incorporation of 14C-leucine into proteins that were precipitated with the anti-casein antibody decreased during culture. The addition of prolactin to hormonal combination of insulin and cortisol caused large stimulation of rates of casein synthesis. Maximum incorporation of leucine was attained between 3 and 5 days of culture in the presence of 0.5 microgram ml-1 of prolactin. Prolactin stimulated-casein and total protein synthesis were not consistently affected by the addition of L-T3 or progesterone. The inhibition of DNA synthesis by hydroxyurea or cytosine-arabinofuranoside had no effect on casein synthesis in mammary explants from pregnant goats.