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Biomedical subjects

G Betz

Publications and source records attributed to G Betz.

54 records · Page 3Linked to original sources
PubMed1979

Hydrocephalus and amenorrhea.

A 25-year-old woman was seen for the complaint of secondary amenorrhea. Skull roentgenograms revealed a markedly enlarged sella turcica. Studies of pituitary and hypothalamic function including prolactin were normal. A pneumoencephalogram revealed dilated ventricles and a mass in the septum pellucidum and hypothalamus. Partial removal of this hypothalamic astrocytoma and placement of an interventricular shunt resulted in the return of menses. Recurrent obstruction a few months later resulted in headache, disorientation, and amenorrhea. A shunt was placed again, resulting in clearing of symptoms and a reestablishment of normal menstrual cyclicity. It appears that the occurrence of increased intracranial pressure rather than the hypothalamic tumor caused the amenorrhea.

Adult↗
PubMed1979

Spontaneous feminization and menstrual function developing during puberty in Turner's syndrome.

An 18-year-old patient with Turner's syndrome presented with cyclical vaginal bleeding and spontaneous development of secondary sexual characteristics. She demonstrated classic features of Turner's phenotype, and a culture of blood lymphocytes revealed a 45,XO karyotype. The patient's plasma and urinary estrogen concentrations were similar to those in normal adult women in the late proliferative phase. In contrast, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels were elevated to values seen in postmenopausal women. Dynamic testing revealed no estrogen response to human menopausal gonadotropin (/MG) and a paradoxical fall in estrogen after administration of human chorionic gonadotropin (hCG). Administration of luteinizing hormone-releasing hormone (LH-RH) resulted in an exaggerated response of both gonadotropins. Dilatation and curettage revealed endometrial hyperplasia, and a laparotomy revealed the presence of 2 gonadlike structures. The histologic diagnosis was lutein cyst. Karyotyping of lymphocytes, skin from the abdominal incision, and tissue from both gonadal structures revealed a 45,XO karyotype without evidence of mosaicism.

Adolescent↗
PubMed1978

Stimulatory effect of soluble supernatant on hydroxylase activity of rat testis microsomes.

Addition of soluble supernatant to testis microsomes results in 42% increase in steroid 17,20-lyase activity and a 65% increase in 17alpha-hydroxylase activity. This stimulatory activity could be partially purified by salt fractionation. The activating factor(s) was not removed by dialysis nor did it appear to be lipid. It was destroyed by trypsin. Differential effects of heat were observed with the hydroxylase and lyase activators. The activation did not affect Km but only increased Vmax. The supernatant could be added to each enzyme to the point of maturation. No binding of steroids by the supernatant could be detected. Corpus luteum and placental supernatant did not stimulate enzymic activity, but supernatant from an adrenal adenoma was active.

Animals↗
PubMed1977

Agonadism: case report and review.

A 24-year-old phenotypic girl with primary amenorrhea was referred for further evaluation. The cervix and uterus were absent and no gonadal tissue was present by physical examination or at laparotomy. Her serum FSH was elevated and there was no increase in serum testosterone following HCG stimulation. The defect(s) in this case and similar patients with "agonadism" reported to date are compatible with various genetic hypotheses.

Adult↗
PubMed1976

Heterogeneity of cytochrome P-450 in rat testis microsomes.

Cytochrome P-450 appears to be a component of the steroid-coverting enzymes, 17alpha-hydroxylase and 17,20-lyase, which catalyze sequential steps in sex hormone synthesis. Further evidence indicates that the steroid substrates of these enzymes bind to cytochrome P-450 during catalysis. The present report deals with the problem of whether a single form of cytochrome P-450 mediates both enzyme reactions or whether two enzymes are involved. Both activities are competitively inhibited by a number of the same inhibitors. Because K1 values of competitive inhibitors are dissociated constants, and thus a property of the cytochrome, different magnitudes of K1, determined for the same inhibitor with each enzyme, are consistent with the participation of more than one form of cytochrome P-450. Differences in the K1 values were found to be statistically significant and varied from 3- to 10-fold. Two competitive inhibitors retarded velocities with one reaction but not the other. In addition, the enzyme activities were markedly different in their sensitivity to carbon monoxide inhibition. The conclusion based on these two lines of evidence is that separate enzymes and different forms of cytochrome P-450 are involved in each reaction.

Animals↗
PubMed1975

Participation of cytochrome P-450 in the steroid 17alpha-hydroxylase of testis microsomes.

The effect of metyrapone on the activity of the steroid 17alpha-hydroxylase from rat testis was evaluated. A competitive pattern of inhibition was observed after analysis of data using a least mean squares computer analysis. The substrate for the hydroxylase induced a Type I difference spectrum in an active suspension of Triton treated microsomes. The magnitude of this spectral change was dependent on steroid concentration and was diminished by metyrapone. The effect of metyrapone was abolished at infinite steroid concentration. These results confirm the participation of cytochrome P-450 as a reactant in the 17alpha-hydroxylase reaction.

Animals↗