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Biomedical subjects

R W Hudson

Publications and source records attributed to R W Hudson.

31 records · Page 2Linked to original sources
PubMed1983

Studies of the nuclear 5 alpha-reductase of human prostatic tissue: comparison of enzyme activities in hyperplastic, malignant, and normal tissues.

The nuclear conversion of testosterone (T) to dihydrotestosterone (DHT) was compared in hyperplastic (n = 40), malignant (n = 20), and normal (n = 3) prostatic tissues. Standard assay conditions were 2 microM testosterone, 2.0 mM EDTA, 1.0 mM NADPH, and the nuclear fraction equivalent to 200 mg of prostatic tissue, in 0.1 M N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid buffer (pH 7.4). The Km values were 0.6, 0.5, and 0.3 microM, respectively, for the enzymes in hyperplastic, malignant, and normal tissues. The Vmax values were 42 +/- 17, 4.2 +/- 1.8, and 3.9 +/- 0.9 pmol/mg protein per 30 min of incubation, respectively, for the hyperplastic, malignant, and normal tissues. When DHT formation was measured at T concentrations equivalent to reported endogenous levels, it was found that enzyme activity in the hyperplastic tissue was still greater than that in the other two tissues. The enzyme in the malignant prostate was less efficient than the enzyme in normal tissue in converting T to DHT. These results would suggest that differences in the conversion of T to DHT may explain, at least in part, the higher DHT levels seen in hyperplastic tissue than in either the normal or the malignant prostate and the higher T levels seen in the malignant prostate than in the other two tissues.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1981

The gonadotropin response of men with varicoceles to a four-hour infusion of gonadotropin-releasing hormone.

The serum gonadotropin, testosterone, and estradiol responses to a 4-hour intravenous infusion of gonadotropin-releasing hormone (GnRH) were studied in four groups of men: severely oligospermic men with varicoceles and sperm densities less than 1 X 10(7)/ml, men with varicoceles and sperm densities between 1.1 X 10(7) and 3 X 10(7)/ml, men with varicoceles and sperm densities greater than 3 X 10(7)/ml, and men of normal fertility. Each group had similar preinfusion luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol levels. Both the severely oligospermic men and the men with sperm densities between 1.1 X 10(7)/ml and 3 X 10(7)/ml had excessive gonadotropin responses to the GnRH infusion. The gonadotropin responses of the men with sperm densities greater than 3 X 10(7)/ml were not different from normal. These results demonstrate that men with varicoceles and sperm densities less than 3 X 10(7)/ml have an altered integrity of their hypothalamic-pituitary-testicular axes, which can be demonstrated by their responses to GnRH.

Adult↗
PubMed1980

The gonadotropin response of men with varicoceles to gonadotropin-releasing hormone.

The serum gonadotropin and testosterone responses to 100 micrograms of intravenously administered gonadotropin-releasing hormone (GnRH) were studied, over 180 minutes, in four groups of men: severely oligospermic men with varicoceles and sperm densities less than 10 million/ml, men with varicoceles and sperm densities greater than 10 million/ml, severely oligospermic men without varicoceles, and men of normal fertility. Each group had similar preinjection gonadotropin and testosterone levels. Following the injection of GnRH, the severely oligospermic men with varicoceles had excessive increases in luteinizing hormone and follicle-stimulating hormone levels and a slower return to preinjection values as compared with the other three groups. The responses of the other groups were not different from each other. There was not a consistent increase in testosterone levels in any group during the period of the study. These results suggest that severely oligospermic men with varicoceles have a pantesticular defect in testosterone synthesis and spermatogenesis which can be demonstrated by their response to GnRH.

Adult↗
PubMed1972

Cushing's syndrome in childhood.

A patient with Cushing's syndrome whose clinical manifestations began at approximately 9 years of age was followed for a period of four years. Initial laboratory studies revealed urinary 170HCS and 17 KS levels which were elevated for her age, with a normal diurnal variation of plasma cortisol and normal suppression of urinary 170HCS by 1.5 mg. of dexamethasone daily. It was not until four years after the onset of the disease that laboratory studies unequivocally supported the diagnosis of Cushing's syndrome resulting in definitive therapy. Clinical features consisted primarily of cessation of growth, obesity, and hirsutism, with no evidence of protein depletion. It is suggested that the clinical and laboratory features of Cushing's syndrome in childhood may present differences from those found in the adult. Failure to recognize these differences may result in delay in therapy with subsequent persisting stigmata of the disorder.

17-Hydroxycorticosteroids↗
PubMedDate not supplied

The prolactin response of males to a standard MVO2 treadmill test.

The concentration of serum prolactin in response to a standard MVO2 treadmill stress test to self-perceived exhaustion was investigated in 19 normal healthy males. The prolactin concentration remained stable for an interval of approximately 20 minutes from the beginning of exercise. Peak prolactin levels, observed after the subjects had stopped exercising, indicated a mean 2.6-fold increase over pre-exercise levels. The concentration of prolactin did not increase before an exercise intensity reflecting a VO2 of 40 ml/kg/min had been reached. There was no relationship between the MVO2 of the 19 male subjects and their prolactin increment in response to exercise.

Adult↗
PubMedDate not supplied

Testicular function in hyperthyroidism.

Testicular function was assessed in nine men aged 17 to 35 years and seven men aged 36 to 46 years with Graves' disease. Levels of total testosterone, estradiol, sex hormone binding globulin, luteinizing hormone, and follicle stimulating hormone, and gonadotropin responses to gonadotropin releasing hormone were significantly greater than these levels and responses in age-matched controls. Although the percentage of free testosterone was lower than control values in the hyperthyroid men, calculated levels of free testosterone were not different from normal. Lower than normal percentages of free estradiol values resulted in higher than normal calculated free estradiol levels. As a result, the free testosterone/free estradiol ratio in the men with Graves' disease was lower than normal. Although mean sperm densities in the hyperthyroid men were not different from control values, the percent forward progressive motility of sperm from these men was significantly lower than control values. The hormonal and seminal abnormalities corrected when the patients became euthyroid after radioiodine therapy. The results of this study indicate that hyperthyroid men may have abnormalities in their hypothalamic-pituitary-testicular axes.

Adolescent↗