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Biomedical subjects

S H Hasan

Publications and source records attributed to S H Hasan.

At least 73 records · Page 4Linked to original sources
PubMed1990

Diurnal variation of serum progesterone, but not relaxin, prolactin, or estradiol-17 beta in the pregnant bitch.

The concentrations of progesterone (P), relaxin (Rlx), estradiol (E2) and PRL were measured by specific RIAs in serum samples collected twice daily at 8:00 am and 3:00 pm at weekly intervals after mating and until whelping in five Labrador Retriever bitches. From weeks 3 to 6 of pregnancy, P exhibited a conspicuous and statistically significant diurnal pattern (P less than 0.05), its serum concentration being approximately twice as high at 8:00 am as at 3:00 pm. A similar but nonsignificant trend was observed weeks 2, 7, and 8, and the overall ratio of the am/pm P concentrations was 2.4 +/- 0.28 (P less than 0.001). Rlx, E2, and PRL did not show a diurnal pattern at any time during pregnancy. The glandular sources and regulation of secretion of Rlx were further investigated. Rlx bioactivity was detected in canine placentas and ovaries, providing supportive evidence that these organs may be a dual source of the hormone in canine pregnancy. Injection of ovine PRL in three pseudopregnant bitches significantly increased serum P concentration as compared with seven untreated pseudopregnant controls, but Rlx was not detectable in serum before, during or after PRL treatment. The data support the view that Rlx and P are independently regulated in the bitch; PRL may be a regulator of P, but not of Rlx secretion. However, as PRL showed no diurnal changes in concentration, it does not appear to be directly responsible for the diurnal pattern exhibited by P.

Animals↗
PubMed1986

Studies on the mechanisms of action of progesterone antagonists.

Antigestagens of RU-38.486-type were investigated in different pregnancy models reflecting either "endometrial" or "myometrial" effects. All antigestagens were found effective inhibitors of nidation in guinea pigs. This was evidence for a role of embryonic progesterone in the earliest events of nidation. No comparable inhibition could be obtained by ovariectomy. A more complex pharmacology was found around day 43 p.c. when the abortion was brought about by expulsion. RU-38.486 had marginal activity only. Antigestagens with reduced anti-glucocorticoid activity tended to induce abortions more effectively and faster. Some antigestagen-prostaglandin combinations were found of extreme abortifacient activity. Surprisingly it seemed that anti-glucocorticoid properties in addition to (or rather than) antigestagenic activities bring about this synergism with prostaglandin. The employed guinea pig model for pregnancy termination thus characterized two types of antigestagens: ideal ones for monotherapy or combined use with prostaglandin, respectively. Antigestagens induced a highly sensitive myometrium to prostaglandin-stimulation (Sulprostone) and a marked softening and dilatation of the cervix. Antigestagens perfectly prime the genital tract for oxytocic stimuli, they do not overcome the arrested uterine prostaglandin-secretion of the pregnant uterus at the same time.

Abortifacient Agents, Steroidal↗
PubMed1984

Pharmacokinetics and pharmacodynamics of the ergot derivative, transdihydrolisuride, in man.

Plasma levels and urinary excretion of the dopamine agonist, transdihydrolisuride (TDHL), were measured by radioimmunoassay in healthy male volunteers given TDHL 50 micrograms i.v. and oral doses of 200, 400 and 800 micrograms. Plasma prolactin was also measured by radioimmunoassay. Following i.v. injection, the concentration of TDHL declined with a half-life of 37 +/- 19 min. The total clearance was 38 +/- 27 ml/min/kg and the apparent volume of distribution was 1.3 +/- 0.41/kg. The bioavailability of oral TDHL was proportional to the dose; after 200, 400 and 800 micrograms the bioavailability was 20 +/- 25%, 31 +/- 24% and 48 +/- 26%. TDHL was almost totally metabolized and less than 0.5% of the dose was excreted unchanged in urine in 24 h. Plasma prolactin levels were depressed by 66 +/- 15%, 75 +/- 11% and 80 +/- 7% after TDHL 200 micrograms, 400 micrograms and 800 micrograms. The effect lasted for more than 12 h after the lowest dose and for more than 24 h after 400 and 800 micrograms. Side effects, mainly nausea and headache, only occurred at the two highest dose levels.

Adult↗
PubMed1981

Radioimmunoassay of plasma lisuride in man following intravenous and oral administration of lisuride hydrogen maleate: effect on plasma prolactin level.

The development of a sensitive radioimmunoassay for the determination of lisuride in plasma is described. The antiserum against lisuride-4-hemisuccinate-BSA was raised in rabbits. Using this method the plasma levels of lisuride were monitored following one intravenous (25 microgram) and two oral (100 microgram and 300 microgram) doses of lisuride hydrogen maleate in three female and three male volunteers (intra-individual comparison). The plasma prolactin was also determined by radioimmunoassay. Following i. v. injection, the concentration of lisuride declined in three phases, with half-lives of 5 min, 25 min and 2 h. The total plasma clearance of 800 +/- 250 ml X min-1 was in the range of "plasma flow" through the liver. In agreement with the high rate of biotransformation, the bioavailability of lisuride administered orally was 10% +/- 7% of the 100-microgram dose, and 22% +/- 7% of the 300-microgram dose. The plasma prolactin was lowered to 3%-18% of its pretreatment value depending on the route of administration and the dose. The reduction appeared to be short-lived and to be directly dependent on the plasma concentration of lisuride. Following intravenous injection, the prolactin level declined after a so far unexplained lag-time of 0.5 h.

Administration, Oral↗
PubMed1980

Disturbances in sexual differentiation of rat foetuses following spironolactone treatment.

Pregnant rats were treated with 40 mg spironolactone (sp) po from the 13th to the 21st day p.c. The foetuses were prepared and histologically examined on day 22. The male foetuses showed distinct signs of feminization especially of the external genitalia. The anogenital distance was nearly 48% shorter than that of the controls. The prostatic utricle persisted more distinctly, and the number and size of the prostatic buds were significantly reduced. The degree of feminization of the male foetuses which is achieved under the influence of sp (40 mg/day) is the same as that which can be induced by 1--3 mg cyproterone acetate.

Animals↗
PubMed1979

Role of the pituitary gland in experimental hormonal induction and prevention of benign prostatic hyperplasia in the dog.

The antiandrogen, cyproterone acetate (CPA), prevents development of prostatic hyperplasia, induced in castrated dogs by a 6 month-treatment with 5 alpha-androstane-3 alpha, 17 beta-diol (A)alone or in combination with 17 beta-oestradiol (E2). The immunoperoxidase technique was used to study functional cell types in the pars distalis of the pituitary gland and to detect growth hormone (GH) and prolactin (PRL) target sites in the prostate gland. Homologous radioimmunoassays for estimation of serum canine GH and PRL concentrations were also performed. Treatment with the combinations A + E2 and A + E2 + CPA resulted in morphological indications of stimulated GH and PRL cells and depressed gonadotrophs. This correlates well with an increase in PRL-dependent staining in glandular epithelium and fibromuscular tissue of the prostate gland. However, basal serum PRL and GH levels were not significantly affected. Treatment with A and A + E2 stimulated, while additional treatment with CPA clearly suppressed adrenocorticotrophin/melanotrophin (ACTH/MSH) cells. These findings indicate that an endocrine imbalance in hypothalamic-pituitary-adrenal function may be involved in induction and prevention of prostatic hyperplasia in the dog.

Androstane-3,17-diol↗
PubMed1977

Homologous radioimmunoassay for canine prolactin and its application in various physiological states.

The purification of canine prolactin and the development of an homologous radioimmunoassay including several physiological studies in the Beagle dog are described. The assay measured immunoreactive canine prolactin with a sensitivity limit of 0-6 ng/ml. Purified canine luteinizing hormone gave no significant inhibition in the assay whereas purified canine growth hormone inhibited the binding of 125I-labelled canine prolactin to antiserum only at very high dose levels. In Beagle dogs. basal serum prolactin concentrations were in the range 1-2 ng/ml in normal male, normal female (metoestrus and anoestrus) and oophorectomized-hysterectomized female dogs. The prolactin concentration in one sample of amniotic fluid was in the same range, while in hypophysectomized male dogs no serum prolactin could be detected by our assay system. Serum prolactin concentrations tended to increase during late pregnancy and parturition, remaining high during the first 9 days of lactation. In consequence, a negative correlation was suggested between serum prolactin and serum progesterone concentrations.

Animals↗
PubMed1976

The influence of pharmaceutical compounds on male fertility.

1. Steroid hormones can affect spermatogenesis and thereby fertility directly and/or indirectly. All antigonadotropically active steroids inhibit spermatogenesis via inhibition of gonadotropin secretion, mainly that of H. Androgens and steroids occurring in the biosynthetic chain of testosterone synthesis have a direct promoting effect on spermatogenesis if applied in high doses. It has not been possible as yet to make clinical use of this positive effect since it is obviously not possible to achieve the necessary intratesticular androgen concentrations. 2. As concerns the different androgens and the steroids in the androgen biosynthetic chain, and also all synthetic anabolics, there is no parallelism between the direct spermatogenic activity, the androgenic activity and the antigonadotropic activity. 3. Estrogens and synthetic gestagens do not inhibit spermatogenesis directly at the testicular level. All effects of estrogens can be abolished experimentally by adequate substitution with gonadotropins or androgens, or a combination of androgens and gonadotropins. 4. Only those antiandrogens inhibit spermatogenesis with additional antigonadotropic properties (e.g. cyproterone acetate). Pure antiandrogens, like flutamide or cyproterone, have a slight and transient influence on spermatogenesis at the most. If at all, they merely cause transient subfertility. 5. Beside steroids and several centrally active pharmaceutics (e.g. psychotropic drugs and several antihypertensive compounds), only siloxanes and methallibur seem to affect spermatogenesis via inhibition of gonadotropin secretion. Other antispermatogenic agents act by inhibition of mitosis (Colchicine, alkylating agents) or presumably via damage of the Sertoli cells. 6. Based on present knowledge, contraception in men could be principally managed by administration of a) androgens alone, b) gestagen/androgen combinations, c) estrogen/androgen combinations, d) certain antiandrogens. 7. The difficulties of contraception in men by steroid hormones or steroid hormone combinations have been pointed out. As regards the usefulness of antiandrogens for contraception, no definite conclusions can be drawn at the moment. All non-steroidal inhibitors of spermatogenesis which have been found up to the present are not suitable because of toxic effects.

Androgen Antagonists↗
PubMed1974

Radioreceptor assay of human chorionic gonadotropin: detection of early pregnancy.

A rapid, sensitive, and specific radioreceptor assay for the determination of human chorionic gonadotropin and luteinizing hormone in plasma is described. Plasma membranes of bovine corpora lutea of early pregnancy, which bind biologically active labeled human chorionic gonadotropin, have been used as receptor. Pregnancy could be detected by assaying the gonadotropin in plasma samples obtained from day 6 to 8 after conception.

Acromegaly↗