Of 605 hyperprolactinaemic sera (prolactin > 1000 mU l-1 determined with PRL DELFIA, Wallac) in the routine diagnostic (PRL was measured in 10,737 sera) 26% had an increased amount of PRL with molecular weight (MW) = 150-170 kD (150-170 kD PRL or bigbig PRL). In a series of serum samples from 660 healthy subjects, only one female with hyperprolactinaemia due to increased 150-170 kD PRL was found. The 150-170 kD PRL constituted less than 1% of the total PRL found in 11 patients with prolactinoma (macroprolactinoma, PRL 8800-500,000 mU l-1). When determined with five different commercially available immunometric assays, the PRL values in the sera with large amounts of 150-170 kD were increased in all sera in four of five assays, although they varied widely. The clinical implications of hyperprolactinaemia due to increased 150-170 kD PRL are still uncertain.
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.
Three healthy male volunteers, 28\p=n-\35 years old, were given an intravenous dose of 12.5, 25, 100, 200, 400, 800, and 1200\g=m\g of synthetic gonadotrophin-releasing hormone (LH/FSH-RH) in order to determine the dose\x=req-\ response relationship. The resulting log dose-response curve between interstitial-cell stimulating hormone (ICSH) and LH/FSH-RH was approximately linear between the 12.5 and 400 \g=m\g doses. The smallest dose that significantly (P < 0.05) increased the mean serum ICSH levels was 25 \g=m\g, and 400 \g=m\g of LH/FSH-RH was the minimum dose that produced the maximum ICSH response. The increments in serum follicle-stimulating hormone (FSH) were much less than the corresponding serum ICSH increments, and the log dose-response curve was not linear. The effect of increasing age on the gonadotrophin response to LH/FSH\x=req-\ RH was studied in 50 male subjects, 20\p=n-\89 years old, without evidence of endocrine disease. They were given 100\g=m\g of LH/FSH-RH each. A reduction in the mean response for both ICSH and FSH was observed after the age of 70, and this was most clearly seen in the group of males 80\p=n-\89 years old. Therefore the interpretation of the LH/FSH-RH tests, at least in males, will require age-specific ranges of normal ICSH and FSH responses.Serum testosterone levels were determined in 48 of the male subjects investigated, and the mean serum levels remained within the same range ') Fellow of The Norwegian Research Council for Science and the Humanities.2) Fellow of Norsk Forening til Kreftens Bekjempelse.
A radioimmunoassay for human pituitary luteinizing hormone (LH) using charcoal for the separation of free from antibody-bound hormone is described. The ability of the various types of charcoal preparations tested to separate free from antibody-bound hormone differed greatly as did the amount required to give maximum adsorption of free hormone. It was also found that the adsorption of free and antibody-bound hormone was greatly influenced by the presence of other proteins. Hence it was necessary to add human serum to the standard tubes before the addition of the charcoal-dextran suspension, in order to compensate for the difference in protein composition between the standards and the serum samples. Two antisera obtained from rabbits immunized with human chorionic gonadotrophin (HCG) were used. One of the antisera had an affinity to human thyroid-stimulating hormone (TSH) and human follicle-stimulating hormone (FSH) of less than 10% as compared to that of LH, while the other had an affinity of about 30 % as compared to that of LH.
The rapid iv administration of 0.5 mg of synthetic thyrotrophin-releasing hormone (TRH) increased the serum thyroid-stimulating hormone (TSH) concentration in 20 normal subjects from baseline levels of 2.0 ± 0.5 ng/ml (sem) to peak values of 6.0 ± 0.7 ng/ml (sem) in women and 4.5 ± 0.5 ng/ml (sem) in men. The maximal increase occurred 30 min after TRH. The serum growth hormone (HGH) concentrations increased from baseline levels of 2.6± 1.0 ng/ml (sem) to peak values of 7.8± 1.3 ng/ml (sem) in women. In men there was no rise in the serum HGH concentrations. The serum levels of luteinizing hormone (LH) and folliclestimulating hormone (FSH) did not change significantly. In patients with hyperthyroidism the serum TSH concentrations did not change following TRH. Patients with primary hypothyroidism showed an exaggerated and prolonged increase in serum TSH concentrations after TRH administration. A routine TRH-stimulation test is proposed.
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