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Biomedical subjects

A Aakvaag

Publications and source records attributed to A Aakvaag.

At least 109 records · Page 6Linked to original sources
PubMed1978

Hormonal changes in serum in young men during prolonged physical strain.

The endocrine response to severe physical strain including lack of sleep has been investigated in army personnel during a combat course of 5 days' duration. The thyroxine (T4) concentration in serum increased during the first 24 h, and then declined at a rate corresponding to a halflife of 7.6 days and on day 6 had reached the lowest level, 55 ng/ml. Triiodothyronine (T3) displayed a similar pattern, although an increase during the first 24 h could not be demonstrated. Within 48 h after the course T4 had returned to normal, whereas the serum level of T3 was significantly below the level before the course (p less than 0.05). The serum level of TSH was suppressed during the course. The serum level of prolactin was significantly suppressed and growth hormone was markedly elevated during the course with a significant negative correlation (r=-0.6) between the two. In agreement with a previous report, there was a rapid and sustained suppression of the serum level of testosterone to a mean level of 1.1 ng/ml on day 5. Short periods of sleep (3--6 h) were shown to be effective in reversing the changes described in this paper, especially for growth hormone, prolactin, and testosterone.

Follicle Stimulating Hormone↗
PubMed1978

On gestagen treatment of advanced prostatic carcinoma.

Depostat treatment was found to reduce plasma testosterone and to have a gonadotrophin suppressive effect in males. In our study the clinical effect on prostatic cancer was, however, disappointing when compared to the well established effect of orchiectomy. The therapeutic failure of Depostat might be related to the incomplete suppression of plasma testosterone compared to that observed after orchiectomy.

Adenocarcinoma↗
PubMed1977

Hormone changes in patients with prostatic carcinoma during treatment with estramustine phosphate.

Hormone analyses of plasma were done on 9 patients with prostatic carcinoma before, during and after treatment with estramustine phosphate. In previously untreated men estramustine phosphate suppressed the plasma testosterone levels. Furthermore, suppression of increased gonadotropins was obtained in irradiated or orchiectomized patients. These hormone changes were caused by high plasma levels of estradiol and/or total estrogens during treatment, with estramustine phosphate, which were still present 2 to 3 months after discontinuation of the drug. We conclude that estramustine phosphate acts, at least partially, as an estrogen and may cause estrogen-dependent side effects.

Castration↗
PubMed1976

Testicular function after combination chemotherapy for Hodgkin's disease.

Fertility was estimated by sperm counts and hormone assays in 8 patients treated for Hodgkin's disease with at least 6 courses of combination chemotherapy. This consisted of an alkylator (mechloretamine or cyclophosphamide), a vinca alkaloid (vinblastine or vincristine), procarbazine and prednisone. Azoospermia was found in 7 of the 8 patients on examination 12-29 months after termination of chemotherapy. In 1 patient semen quality improved gradually, and a sperm count of 5 mill/ml was found at 21 months. Serum FSH levels were increased in all but 1 patient who was, nevertheless, azoospermic. The levels of testosterone and LH were generally within normal limits. Thus, the germinal tissue is seriously damaged by this type of chemotherapy. The resulting infertility seems to be complete and of long duration. Partial recovery of spermatogenesis may, however, sometimes take place after prolonged unsustained remission.

Adult↗
PubMed1976

Testicular function after radiotherapy to inverted 'Y' field for malignant lymphoma.

Testicular function was estimated by sperm counts, hormone assays and recording of reported conceptions in 9 patients irradiated for malignant lymphoma. The treatment had been an inverted 'Y' field including the inguinal regions with, in addition, a mantle field in 8 patients. Azoospermia or severe oligozoospermia was found in all but 1 patient, and the FSH levels were uniformly elevated. Testosterone and LH were within normal limits except in 2 patients with slightly subnormal testosterone levels. 7 of the patients were married to women of fertile age, and in 3 cases the wife became pregnant and give birth to a healthy child. The time lapses from irradiation to conception were 18, 40 and 57 months. 2 of these patients had severe oligozoospermia on examination 2 and 4 months respectively from conception. Thus fertility may possibly be underestimated by sperm counting and hormone assays after this type of radiotherapy.

Adult↗
PubMed1976

Androgen receptors in the anterior pituitary and central nervous system of the androgen "insensitive" (Tfm) rat: correlation between receptor binding and effects of androgens on gonadotropin secretion.

The cytosol fractions of the anterior pituitary, hypothalamus, preoptic area and brain cortex of androgen "insensitive" (Tfm) rats possess androgen receptors. However, in the Tfm rats the androgen binding per mg protein was only 10-15% of that in the corresponding normal littermates (Nl). The physicochemical properties of the androgen receptors in the anterior pituitary of the Tfm rat were indistinguishable from those of the normal rat. Thus, no distinctive differences were observed with regard to electrophoretic mobility in 3.25% polyacrylamide gels, isoelectric point (pI=5.8), binding affinity (KD=1.5 X 10(-9)M), temperature stability, sulfhydryl dependence and steroid specificity. It is, therefore, likely that the very low androgen binding capacity by the anterior pituitary and the central nervous system is due to an extreme reduction in the receptor number rather than to the presence of abnormal receptors. Since in the Tfm animals the androgen receptor number is reduced by 85-90%, it is to be expected that very high doses of androgens would be required to achieve hormonal effects. In fact, low doses of 5alpha-dihydrotestosterone propionate (50 mug/100 g body weight) given sc daily for 12 days had no effect on serum levels of LH and FSH. However, very high doses (2 mg/100 g body weight) of testosterone propionate and 5alpha-dihydrotestosterone propionate, which maintained circulating androgen levels above 20 ng/ml, significantly reduced serum gonadotropin levels in castrated Tfm rats. In normal littermates both low and high doses of the androgens suppressed gonadotropin secretion to low levels. These findings strongly indicate that androgen receptors are essential to androgen action on the anterior pituitary and central nervous system in the rat. The serum levels of testosterone (7.7+/-0.15 (SE) ng/ml) and 5alpha-dihydrotestosterone (0.37+/-0.06 ng/ml) were significantly higher in intact Tfm rats than in normal littermates (2.6+/-0.03 and less than 0.1 ng/ml, respectively). The failure of the elevated concentrations of serum androgens to reduce the high serum levels of LH and FSH in intact Tfm rats is most likely due to the extreme reduction of the androgen receptor number and the consequent insufficient hypothalamic and/or pituitary response to androgens.

Adrenal Glands↗
PubMed1976

External high-voltage radiotherapy of carcinoma of the prostate and the regional lymph nodes.

External high-voltage radiotherapy of carcinoma of the prostate and the field of regional lymphatic spread leads to regression of the tumour in over half the cases. The definite response to radiotherapy does not seem to be related either to the degree of histological differentiation or to the palpable extent of the tumour in the pelvis and is not always seen until at least 6 months from the end of treatment. Radiotherapy has a good palliative effect. Oestrogens need not be administered during irradiation and subsequently as long as no disease activity is detectable.

Cell Differentiation↗
PubMed1975

Androgen binding proteins in the anterior pituitary, hypothalamus, preoptic area and brain cortex of the rat.

The cytosol fractions of the anterior pituitary, hypothalamus, preoptic area and brain cortex of castrated male rats have been found to possess specific androgen binding proteins. The physicochemical characteristics of these binding proteins appear to be very similar. Thus, they were excluded by Sephadex G-100 gel and had a sedimentation coefficient of 6-7S by sucrose gradient centrifugation. The protein nature of the androgen binding components was supported by the fact that protease, but not DNase and RNase eliminated the binding of androgens. In addition, the elimination of the binding by 1 mM p-chloro-mereuriphenylsulfonate (PCMPS) and by heat treatment at 45 C for 30 min indicate that free sulfhydryl groups are necessary for androgen binding and that the proteins are thermolabile. Testosterone, 5alpha-dihydrotestosterone and the antiandrogen Cyproterone acetate were found to possess a much higher affinity than 17beta-estradiol and cortisol for the binding components. Dissociation studies revealed that [3H]testosterone is not easily displaced by unlabeled androgens. In the anterior pituitary, hypothalamus and preoptic area testosterone accounted for the major part of the radioactive material in the total tissue homogenates and also for the greater part of the bound radioactivity 15 min after in vivo administration of [3H]testosterone. [3H]17beta-estradiol accounted for less than 3% of the bound radioactivity under these conditions. If binding of a steroid sex hormone by specific proteins is a prerequisite for the hormonal action, the present study indicates the potential for a direct effect of androgens on the target cells of the anterior pituitary and of the central nervous system

Animals↗
PubMed1975

Plasma levels of estradiol and plasma protein binding of sex steroids in dogs. An investigation with special reference to development of hip dysplasia in growing individuals.

Peripheral plasma levels of estradiol were determined in 39 dogs of three breeds (Greyhound, German Shepherd, Golden Retriever). Blood samples were collected weekly from 3 weeks up to 17--21 weeks of age. The pups from all three breeds had mean levels of estradiol varying between 4--8 pg/ml. The lowest levels were found in pups which developed hip dysplasia. There was a significant difference (0.01 less than p less than 0.005) between the estradiol levels of German Shepherd pups with normal and dysplastic hip joints. In female Greyhounds, the peripheral plasma levels of estradiol were examined from 17 weeks of age through the first heat. No increase of the estradiol level was seen with increasing age. The ability of dog plasma to bind dihydrotestosterone (DHT) and estradiol was examined in three dogs. It was found that there are at least three types of binding components for DHT: one with high affinity and extremely low capacity, which is heat labile, another which is also heat labile but has a high capacity and low affinity, and a third which appears to be albumin. Estrogen administration to the three dogs lowered the binding of DHT. It was concluded that it is most unlikely that hyperestrogenism is an etiologic factor in canine hip dysplasia. Unphysiologically high doses of estradiol have been used for experimental induction of hip dysplasia. There is a possibility that the levels of plasma proteins, which bind steroids, could be of importance for the etiology of hip dysplasia. A low plasma level of estradiol could be biologically highly significant if there is a low level of a specific binding protein.

Animals↗