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Biomedical subjects

C Hirschhäuser

Publications and source records attributed to C Hirschhäuser.

At least 19 recordsLinked to original sources
PubMed1979

Study of testicular feedback in male rats using artificial cryptorchidism as a model.

Plasma LH, FSH and testosterone were measured in testosterone-treated and untreated cryptorchid and castrated male rats. Exogenous testosterone prevented the increase in basal LH but not FSH levels seen in the untreated cryptorchids. Increases in plasma LH and FSH in response to LH-RH were greater in the cryptorchid as compared to the control group and this could not be reversed by exogenous testosterone, suggesting that spermatogenesis-related feedback factors regulate LH as well as FSH at the pituitary level in the intact rat. The results were consistent with a reduced but nevertheless significant secretion of inhibin by the cryptorchid testis. Basal plasma testosterone levels and ventral prostate weights were not significantly different from intact animals.

Androgens↗
PubMed1978

[Inhibin-like activity in human ovarian follicular fluid (author's transl)].

A steroid-free proteinaceous substance with inhibin-like activity has been extracted from human ovarian follicular fluid by alcohol precipitation. This substance was capable of inhibiting the ovarian weight increase of hCG-treated immature female rats and also of suppressing the post-castration rise of serum FSH levels in immature male rats. Follicular fluid from small follicls obtained from regularly cycling women was--on the basis of protein- found to be more active than cystic follicular fluid obtained from a premenopausal woman. The possible role of inhibin in the regulation of human ovarian cycle has been discussed.

Animals↗
PubMed1978

The effect of local testicular irradiation on testicular histology and plasma hormone levels in the male rat.

Adult male rats were subjected to local testicular irradiation, plasma hormone levels and testicular histology being quantified at intervals up to 52 days thereafter. LH and FSH increased coincidently with spermatid but not with spermatocyte or spermatogonia depletion. Testosterone levels seemed to decrease but this effect was not significant. Oestradiol levels showed no significant changes. From the correlations between the various parameters it was concluded that the lack of inhibin was the main cause of the increase in both LH and FSH and that spermatids provide the signal for production of this non-steroidal inhibitor. The site of inhibin production was not definitively established but the results would be consistent with production of inhibin by the Sertoli cells in association with spermatids.

Animals↗
PubMed1975

Changes in enzyme pattern of Ehrlich ascites tumor cells following serial cultivation in media with increased (hypertonic) NaCl content.

Adaptation of Ehrlich ascites tumor cells to serial cultivation in media with progressively elevated (hypertonic) NaCl content ("high NaCl"-tolerant cells) has resulted in progressive increases of the cellular activities of NAD-dependent glycerol-3-phosphate dehydrogenase (EC 1.1.1.8), NAD-dependent malate dehydrogenase (EC 1.1.1.37), glutamate--oxalacetate transaminase (EC 2.6.1.1), NAD (P)-dependent glutamate dehydrogenase (EC 1.4.1.3), NADP-dependent isocitrate dehydrogenase (EC 1.1.1.42). The activities of glutamate-pyruvate transaminase (EC 2.6.1.2.) and of glycolytic enzymes as phospho-fructokinase (EC 2.7.1.11), glyceraldehydephosphate dehydrogenase (EC 1.2.1.12) and lactate dehydrogenase (EC 1.1.1.27) were only slightly and not in progressive manner (in response to the progressive increase of the environmental NaCl concentration) affected. These changes are discussed with respect to a metabolic pattern of these "high NaCl"-tolerant cells which is compatible with increased energy requirements, especially for active cation transport. It is suggested that these increased cellular enzyme activities reflect an increased transfer of reducing equivalents across mitochondrial membranes (via the "glycerophosphate cycle and the malate-aspartate shuttle") and possibly a stimulated lipid metabolism. These alterations in the level of enzyme activities must be regarded asan adaptive cellular response to the "high NaCl" environment, since readaptation to growth in regular isotonic media resulted in a reversion to the enzyme pattern characteristic of the parent cells.

Alanine Transaminase↗
PubMed1975

Testosterone undecanoate: a new orally active androgen.

Oral testosterone undecanoate (TU) in arachis oil has been evaluated with a view to its possible use as a means of androgen replacement therapy. A single 100 mg dose was found to elevate plasma androgen levels and urinary 17-ketosteroid excretion in 6 normal men. Ninety mg/day and 60 mg/day doses taken by a hypogonadal man resulted in sustained levels of androgen which appeared physiological when measured by radioimmunoassay without chromatography. However, upon separation of the steroids by chromatography it was found that much of the androgen present was in fact dihydrotestosterone not testosterone. Both TU and dihydrotestosterone undecanoate were detected in plasma by gas chromatography and it is suggested that the ester is absorbed as such from the intestine and the unesterified steroid subsequently released by hydrolysis. The convenience of oral administration, the resulting prolonged elevated plasma androgen levels and the probable lack of deleterious effects on the liver may render oral TU of value where androgen replacement therapy is indicated.

17-Ketosteroids↗
PubMed1975

[The filtration capacity of the cervix uteri (in-vitro studies) (author's transl)].

In-vitro experiments had been undertaken in order to clarify sperm selection by cervical mucus. Sperm samples, preferably with a high rate of abnormal cells, were obtained from fertile and infertile men for 35 penetration tests. Cervical mucus was collected from fertile women during praeovulatory phase. The penetration tests resulted in a statistically high amount of normal sperm cells which had migrated through cervical mucus as compared to abnormal cells. The significance of this filtration capacity of the cervical mucus will be discussed.

Cervix Mucus↗