Effects of bromocriptine on plasma testosterone and gonadotropin levels and testicular lipid fractions in adult rats

Summary Bromocriptine treatment of adult male rats resulted in a decrease in testicular testosterone (T) content and a reduction in plasma T levels. This was accompanied by increase in testicular total lipids and cholesterol and depletion of testicular phospholipids.Acknowledgments. We thank Dr R. L. Elton of Sandoz Pharmaceuticals for provision of CB-154. This work was supported by the Rockefeller Foundation, New York, NY, and by NIH grants HD 12642 and P-30 HD 10202 (Radioimmunoassay Core).     

Sertoli cells of adult rats in vitro. II. Effect of different steroid precursors on estradiol 17β-synthesis

Summary The estradiol 17-synthesis by ⁴ pathway has been studied in homogenous cultures of Sertoli cells isolated from adult rat testes. The data reported clearly demonstrate that progesterone, androstenedione, testosterone and estrone induce an increase of the estradiol 17-production.This work was partially supported by grants No. 77.01322.04 and No. 77.01958.04 from the Consiglio Nazionale delle Ricerche.The excellent technical assistance of Antonio Muller and Massimo Rosati is deeply appreciated.     

Plasma testosterone and dihydrotestosterone in normal and abnormal pregnancy

Summary The concentration of plasma testosterone (T) and dihydrotestosterone (DHT) was determined in 2 groups of nonpregnant and pregnant women. The 1st group consisted of normal women and the 2nd of women with recurrent pregnancy disorders of unknown etiology. Significantly higher concentration of plasma DHT in nonpregnant women from the 2nd group was found (44.9±22 ng/100 ml) as compared to nonpregnant normals (24.2±5.2 ng/100 ml), p<0.01. There was no difference in the concentration of plasma T between the groups studied (p=0.165).Acknowledgment. The authors thank Prof. A. Draani, Mrs Lj. Vukeli and Mrs Z. Tomakovi for their collaboration in this study. This study was supported by the Scientific Fund of SR Croatia (Zagreb), SIZ V.     

Steroid hormones in the testicular tissue ofGallus domesticus

Riassunto Nel tessuto testicolare diGallus domesticus sono stati identificatii seguenti ormoni steroidi: pregnenolone (127 µg/kg), progesterone (66,5 µg/kg), androstenedione (2,4 µg/kg), testosterone (35 µg/kg), 20-idrossipregn-4-ene-3-one (30,5 µg/kg). Questi risultati dimostrano che il testicolo di pollo secerne gli steroidi della principale via biosintetica degli androgeni. La concentrazione relativamente alta di 20-idrossipregn-4-ene-3-one viene discussa alla luce delle ricerche sul metabolismo in vitro del progesterone.

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This investigation was supported by a research grant No. HD 01477-07 from the National Institute of Child Health and Human Development, Public Health Service, USA, and by the Consiglio Nazionale delle Ricerche of Italy.     

Vitellogenin synthesis induced in locust fat body by juvenile hormone analog in vitro

Summary Fat bodies from adult females ofLocusta migratoria continue to synthesize vitellogenin and other proteins when cultured in vitro. A strong secondary induction of vitellogenin synthesis was obtained in fat bodies cultured in the presence of methoprene, and a weaker but significant primary induction was also obtained using higher doses (>100 g) of methoprene.This work was carried out in Dr G.R. Wyatts Laboratory and I thank him for helpful discussions. I also thank Dr G. Staal (Zoecon Corp.) for supplying the methoprene and Pfizer Inc. for rimocidin sulfate. This research was supported by grants from the US NIH (HD 02176) and Canada NSERC.     

Capillary blood flow in the testes and testosterone secretion in the starved rat

Summary The average capillary blood flow in the testes was found to be 181 l/min/g testis tissue (n=19) in rats starved for 5 days and 273 l/min/g (n=18, p<0.01) in the control group. Plasma testosterone was significantly decreased in the starved animals (1.00±0.06 ng/ml vs 5.43±0.63 ng/ml). When starved and control rats were stimulated with human chorion gonadotropin, testosterone values in plasma were greatly increased in both groups. The capillary blood flow was not altered. The data indicate that human chorion gonadotropin can stimulate testosterone production in the starved rat without influencing the reduced capillary blood flow.     

Anti-androgenic action of cyproterone acetate in the epididymis of the rhesus monkey

Summary Cyproterone acetate (1 M) inhibited the binding of labeled testosterone (T) and dihydrotestosterone (DHT) in the caput and cauda epididymides of the rhesus monkey. The same concentration of the anti-androgen failed to inhibit androgen binding in the ductus deferens, prostate and seminal vesicles.The investigation was supported by financial assistance from the Indian Council of Medical Research and the University Grants Commission. CA was a gift from Dr. F. C. Neumann, Scherring AG, Berlin.     

High affinity binding of labeled androgens in the androgen-target tissues of the male rhesus monkey

Summary High affinity testosterone (T)-specific and dihydrotestosterone (DHT)-specific binding sites exist in a 12 ratio in the cytosol fractions of the caput epididymidis, prostate, seminal vesicles and the ductus deferens of the rhesus monkey. The number of androgen-binding sites in the caput epididymidis is 3 times greater than that of the other 3 tissues.This investigation was supported by financial assistance from the Indian Council of Medical Research and the University Grants Commission.     

Prolactin and growth hormone do not interfere with the response of mouse testes to hCG in vitro

Summary In incubations of decapsulated mouse testes with a maximally stimulating dose of hCG, the accumulation of testosterone was not affected by the addition of PRL at concentrations from 0.1 to 50 μg/ml or GH at concentrations from 0.5 to 25 μg/ml. This work was supported by NIH through grants HD 12642 and HD 12671. We thank NIAMDD for the supply of pituitary hormones and Dr B.V. Caldwell for antiserum to testosterone.     

Die Wirkung einer Leberschädigung durch Thioacetamid auf die mikrosomale Aromatisierung von Testosteron bei der Ratte

Summary Rat liver microsomes, NADPH-regenerating system, and 1, 2-³H-testosterone have been incubated in vitro. The loss of tritium from the steroid, associated with aromatization of testosterone, was linear with time for 20 min and required NADPH. Pre-treatment of the rats with thioacetamide raised the liberation of tritium from 1, 2-³H-testosterone. The results suggest that liver damage by thioacetamide in rats may give rise to increased aromatization of testosterone.     

The toxicity of twoBacillus thuringiensis δ-endotoxins to gypsy moth larvae is inversely related to the affinity of binding sites on midgut brush border membranes for the toxins

Summary The-endotoxin fromBacillus thuringiensis subspecieskurstaki strain HD1-9 is almost 400 times more potent than the-endotoxin from strain HD-73 as a gypsy moth larvicide. The two-endotoxins compete for a high-affinity binding site on the brush border membrane of larval gypsy moth midguts. The affinity for the-endotoxin from strain HD-73 is much greater than the affinity for the-endotoxin from strain HD1-9.     

Metabolism of C19-steroids in testicular tissue of the newtTriturus vulgaris,during and after breeding

Summary Incubation studies with testicular homogenates ofTriturus vulgaris showed that testosterone was quantitatively the most important metabolite of dehydroepiandrosterone and androstenedione during breeding. After breeding the recovery of testosterone declined. This suggests that 17-hydroxysteroid dehydrogenase may be regulated for the needs of testicular androgen production.     

Alzheimer’s disease: the impact of age-related changes in reproductive hormones

The relationship between menopause and cognitive decline has been the subject of intense research since a number of studies have shown that hormone replacement therapy could reduce the risk of developing Alzheimers disease in women. In contrast, research into andropause has only recently begun. Furthermore, evidence now suggests that steroidogenesis is not restricted to the gonads and adrenals, and that the brain is capable of producing its own steroid hormones, including testosterone and estrogen. Sex hormones have been demonstrated to be of critical importance in the embryonic development of the central nervous system (CNS); however, we are only just beginning to understand the role that these hormones may play in the normal functioning and repair of the adult mammalian CNS. This review will summarize current research into the role of androgens and andropause on cognition and the possible mechanisms of action of androgens, with particular reference to Alzheimers disease.     

Hemmung der experimentellen,testosteron-bedingten Epidermisproliferation an der weiblichen Ratte durch ein synthetisches Phenanthrenderivat mit antiandrogener Wirkung

Summary In the female rat, testosterone propionate-induced proliferation of the epidermis (acanthosis and mitotic activation) is inhibited in proportion to dosage by a phenanthrene derivative with antiandrogenic action.     

Identification of steroid hormones fromLacerta sicula testes

Riassunto Gli autori hanno analizzato gli steroidi presenti nel tessuto testicolare diLacerta sicula. Sono stati identificati i seguenti steroidi: progesterone, androstenedione, testosterone, androsterone, deidroepiandrosterone, pregnenolone, 20-idrossipregn-4-ene-3-one, estradiolo-17, estrone. Viene discusso il rapporto progesterone androstenedione testosterone, paragonandolo a quello trovato in altri vertebrati inferiori.     

Deciduoma formation in rats with cornified vagina

Summary In female rats given a single injection of 1.25 mg 5-dihydrotestosterone during neonatal life, reactivity of the vaginal mucosa to hormones was permanently altered, so that the rats, when adult, could show vaginal cornification under the hormonic conditions supportive of development of deciduomata in the uterus.We wish to thank Prof.T. Kimoto of Kawasaki Medical College for valuable advice and information.     

Alzheimer’s disease: the impact of age-related changes in reproductive hormones

The relationship between hormones and Alzheimers disease (AD) has been intensely researched. While the majority of this work has focused on the sex steroids, estrogens, and more recently androgens, a serendipitous patient encounter led one of us (R.L.B.) to question whether other hormones of the hypothalamic-pituitary-gonadal axis might play a role in the pathogenesis of AD. The age-related decline in reproductive function results in a dramatic decrease in serum estrogen and testosterone concentrations and an equally dramatic compensatory increase in serum gonadotropin concentrations. Indeed, there is growing evidence that the gonadotropin luteinizing hormone, which regulates serum estrogen and testosterone concentrations, is an important causative factor in the development of AD. This review provides information supporting the gonadotropin hypothesis. We put forth a novel mechanism of how changes in serum luteinizing hormone concentrations could contribute to the pathogenesis of AD and discusses potential therapeutic anti-gonadotropin compounds.     

Thyroid gland influences the period of hamster circadian oscillations

Summary The locomotor activity of ovariectomized, adult golden hamsters was monitored under constant dim illumination. Thiourea treatment lengthened the period () of locomotor activity of thyroidectomized hamsters in comparison to pre-operative s and in comparison to the s of control hamsters. The results confirm hormonal modulation of the circadian system.Acknowledgments. This study was supported by grant HD-02982. L.J.B. was the recipient of a N.I.M.H. Traineeship (T32-MH-15860-01). We thank D. Frost, J. Budd, B. Ries, M. Darragh and J. Schutz for technical assistance. We are grateful to Drs I. Zucker and L. L. Rosenberg for guidance and helpful comments throughout this study.     

Effects of two kinds of social deprivation on testosterone and estradiol-17β plasma levels in the male rat

Summary The effect of complete and tactile isolation on plasma testosterone and estradiol-17 was studied in male rats at the age of 60 and 180 days. A decrease in the plasma levels of the two hormones was observed.     

Hormonal induction of steroid sulphatase in the mouse

Summary By comparing steroid sulphatase levels per se, and also ratios to -galactosidase, in 6 sets of mice — normal females, entire and castrated males both with and without exogenous testosterone administration — we obtained support for the contention that induction of this enzyme is in part controlled by male hormones.