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At least 145 records · Page 8Linked to original sources
PubMed1975

Role of carbohydrate of human chorionic gonadotropin in the mechanism of hormone action.

The role of the carbohydrate part of human chorionic gonadotropin (hCG) was investigated by measuring the ability of hCG derivatives lacking various sugar residues to bind to rat Leydig cells and stimulate them to synthesize testosterone and cyclic adenosine 3':5'-monophosphate (cyclic AMP). Whereas sequential removal of the sialic acid, galactose, N-acetylglucosamine, and mannose residues led to a progressive increase in the effective dose of the hormone required to stimulate steroidogenesis, it resulted in a marked loss in the ability of the hormone to stimulate cyclic AMP accumulation. Low doses of the glycosidase-treated hormone derivatives were additive with hCG when their ability to stimulate testosterone synthesis was analyzed. Nevertheless, the glycosidase-treated derivatives were potent inhibitors of hCG-induced cyclic AMP accumulation, suggesting that removal of the sugars did not influence binding of the hormone to the cell as much as it reduced the ability of the bound hormone to activate adenyl cyclase. This hypothesis was further supported by our finding that the hCG derivatives were highly effective inhibitors of 125I-hGC binding to the intact cells. Removal of sialic acid and galactose enhanced the inhibition, whereas removal of all the sugar residues only decreased the inhibition slightly. The degree of these effects was comparatively small. The possibility that steroidogenesis and cyclic AMP accumulation are altered independently by hCG stimulation is discussed.

Acetylglucosaminidase↗
PubMed1977

Gonadal function following vasectomy in the rat.

Adult rats were studied at four, eight, and 12 months following vasectomy and sham-operation. The weights of the seminal vesicles, ventral prostate, pituitary, and kidneys were not significantly affected by vasectomy. Testicular endocrine function in vasectotomized rat was transiently stimulated as witnessed by elevation in testicular venous testosterone and androstenedione after four months. There then occurred signs of decline in gametogenic function and atrophy of the testis after 12 months whereas hormonogenesis appeared to remain at normal levels. There was no alteration in the morphology of the epididymis at any of the time intervals of study after vasectomy.

Animals↗
PubMedDate not supplied

Treatment of hirsutism related to micropolycystic ovary syndrome (MPCO) with two low-dose oestrogen oral contraceptives: a comparative randomized evaluation.

In order to evaluate the clinical and endocrinological efficacy of two low-dose oral contraceptives (OC) containing 30 micrograms Ethinylestradiol (EE) and 150 micrograms Desogestrel (DG) and 75 micrograms Gestodene (GD), respectively, an open randomized study was carried out in 34 young hirsute women, matched for body mass index and age. All of them met endocrine and ultrasonic criteria for Micropolycystic Ovary Syndrome (MPCO). The participants were randomly assigned to one of two pill groups (each of 17). The serum values for Total Testosterone (TT), Free Testosterone (FT), Androstenedione (A), Dehydroepiandrosterone (DHEA), Dehydroepiandrosterone Sulphate (DHEAS), 17-Hydroxyprogesterone (17Pg), Sex Hormone Binding Globulin (SHBG), Ceruloplasmin (CP), as well as Ferriman-Gallwey Index (FGI) and Free Androgen Index (FAI) were evaluated prior to and after EE-DG and EE-GD 6 cycle treatment. A significant decrease in TT, FT, A, 17Pg, DHEA, DHEAS, FGI, FAI was observed, SHRG and CP increased significantly. There were no significant differences between the two OC. Our results seem to indicate that both OC are equipotent as far as their pharmacological profile and residual androgenic activity are concerned. Therefore, these OC may represent a highly effective and suitable alternative to the treatment of hyperandrogenism related to MPCO.

17-alpha-Hydroxyprogesterone↗
PubMed1974

Binding of steroids to blastokinin.

The authors studied the binding of steroids with Blastokinin (BKN). They confirm that progesterone is the steroid that has a greater affinity for BKN than estradiol or testosterone; the latter is hardly bound to the protein at all. They also show that the presence of estradiol interferes with the formation phase of the BKN-progesterone complex, while testosterone does not. When the BKN-progesterone complex is already formed, a release of the progesterone occurs only when there is a double concentration of estradiol. The biological importance of this phenomenon is briefly discussed.

Animals↗
PubMed1975

Clinics in endocrinology and metabolism. Investigative procedures.

In patients with hypogonadism, the exact cause of the deficient androgenisation is not always clinically apparent. The data presented demonstrate that by means of hormone measurements, basally or after stimulation tests, the exact level of the lesion can usually be determined. This allows a decision with regard to appropriate therapy to be made on the basis of an accurate diagnosis. In many instances basal measurements of pituitary and gonadal hormones are all that is required to decide the level of the lesion. Care in interpreting basal levels is required, however, in view of methodological limitations and of known physiological variations with age, time of day and hour-to-hour fluctuations. If the basal hormone levels are borderline, or if the 'reserve function' of part or all of the hypothalamic-pituitary-gonadal axis needs to be assessed, than the appropriate stimulation test should be performed. The indication for these stimulation procedures and results obtained in different conditions are described and problems of interpretation discussed.

Adult↗
PubMed1975

An apparently direct inhibitory effect of oestrogen on the human testis.

In men suffering from prostatic cancer, i.v. administration of 12 g diethylstilboestrol diphosphate within 20 days resulted in a decrease of the LH serum level to about 50% (P less than 0.05), whereas the total testosterone level decreased to less than 5% (P less than 0.001) and the apparently free testosterone level to less than 2% of the initial values (P less than 0.001). Hence, the "systemic antiandrogenic effect" of oestrogen can be explained (1) by indirect inhibition of testicular androgen secretion via diminution of hypophyseal gonadotrophin secretion, (2) by direct inhibition of testicular androgen secretion and (3) by elevation of the capacity of testosterone binding beta-globulin.

Aged↗
PubMed1984

Serum total and unbound testosterone and sex hormone binding globulin (SHBG) in female acne patients treated with two different oral contraceptives.

Serum total an unbound testosterone (T) and sex hormone binding globulin (SHBG) levels were studied in fifty-four female acne patients before treatment and during the treatment by two different oral contraceptives, the other containing 0.150 mg desogestrel plus 0.03 mg EE and the other 0.150 mg levonorgestrel plus 0.03 mg EE. Pretreatment values were abnormal in 57% of the patients. A borderline significant correlation between the severity of acne and SHBG was found. Ater six months' treatment a 250% increase in SHBG was seen in desogestrel/EE group and no significant change in SHBG in levonorgestrel/EE group. However, at the same time serum free testosterone fell 60% in both treatment groups. SHBG cannot be the only regulator of serum free testosterone. Acne improved significantly in both treatment groups. It is likely that the improvement was in connection with the free testosterone decrease and the improvement was better in the desogestrel/EE group where also SHBG elevation was seen.

Acne Vulgaris↗
PubMed1980

Chronic treatment with the gonadotropin-releasing hormone agonist D-Ser(TBU)6-EA10-LRH for contraception in women and men.

The stimulatory analogue of luteinizing hormone-releasing hormone (LRH) D-Ser(TBU)6-EA10-LRH was administered subcutaneously (sc) or intranasally to 10 women with amenorrhea and to 44 healthy female and male volunteers. The LRH agonist evoked a pronounced initial release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) but the gonadotropin response decreased during the course of the chronic treatment. Ovulation could not be induced in seven amenorrheic women who were given prolonged treatment with the analogue. In normally ovulating women, ovulation was inhibited during chronic treatment with a daily sc dose of 5 microgram or a daily intranasal dose of 400 microgram. In four healthy men treated with 5 microgram of the LRH agonist daily over 17 weeks basal FSH, LH, and testosterone levels decreased but spermatogenesis and potency were unaffected. The negative effects on testosterone secretion may limit the use of the LRH agonist for male contraception. Chronic intranasal administration of the stimulatory LRH analogue paradoxically inhibited ovulation and proved to be a safe and effective new approach to contraception in women.

Administration, Intranasal↗
PubMed1978

Androgen and estrogen formation in women with ovarian hyperthecosis.

Women with ovarian hyperthecosis were studied and found to have a plasma testosterone production rate of 2.1 mg/day, a value eight times greater than that of nonhirsute, ovulatory women. The severity of hirsutism and virilization in these women was more closely correlated with the amount of testosterone produced than with plasma testosterone concentrations. The mean plasma production rates of androstenedione in these women, 8.6 mg/day, was more than three times that found in young women with no evidence of androgen excess. There was a marked gradient between ovarian and peripheral venous plasma concentrations for both C19 steroids. Following ovarian wedge resection or oophorectomy, there was a precipitous fall in the peripheral venous concentrations of these steroids. These observations support the view that the major source of excess androstenedione and testosterone secretion in these subjects was the ovaries. The rate of estrone formation in these women, 106-345 microgram/day, was the result of extraglandular aromatization of plasma androstenedione.

Adolescent↗