Biomedical subjects
Publications and source records attributed to G T Ross.
Daily determinations of luteinizing hormone activity in plasma throughout a menstrual cycle in ten young women showed a sharp peak of activity lasting less than 48 hours around midcycle and higher mean values during the follicular phase than during the luteal phase in nine instances.
It is not practical to quantitate gonadotropin in the blood of normal men and women by utilizing bioassays. We have developed a method for sensitive, precise, and specific radioimmunoassay of luteinizing hormone (LH) in human serum or plasma. Antisera were developed against human chorionic gonadotropin, and one of these was selected for extensive cross-reaction with human LH. Highly purified LH was radioiodinated by the method of Greenwood, Hunter, and Glover. Separation of antibody-bound from free LH-(131)I was accomplished by a double antibody technique. Dose-response curves for the purifed LH, an impure urinary LH preparation, pituitary powder, and LH in plasma were all identical. Immunoassay and bioassay of impure urinary and pituitary gonadotropin preparations in terms of a common standard resulted in an index of discrimination of close to unity. LH levels in plasma from 32 adult men and 30 women outside the midcycle ranged from 0.6 to 3.2 mmug per ml (1 mmug of our laboratory LH standard is equivalent to 8 mU of the Second International Reference Preparation of Human Menopausal Gonadotropin). Levels were remarkably constant in men from day to day and in women except at midcycle, when a sharp peak occurred lasting less than 24 hours. In all women studied who had a midcycle LH peak, mean plasma LH levels during the follicular phase of the menstrual cycle were higher than mean values obtained during the luteal phase. Prepubertal children had detectable plasma LH, and mean values were only slightly less than in adults. Plasma from castrate men or women or postmenopausal women contained 4.5 to 10.5 mmug per ml. Clomiphene treatment of four men resulted in a doubling of plasma LH in 5 days.
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) have been measured by specific bioassays in pooled urine samples from prepubertal children, aged 2-6 yr, and from male adults. For children the mean urinary excretion of FSH was 2.2 U 2nd International Reference Preparation (2nd IRP) per liter and the mean urinary excretion of LH was 0.44 U 2nd IRP per liter. For adults the mean FSH excretion was 5.6 U 2nd IRP per liter and the mean LH excretion was 4.7 U 2nd IRP per liter. Our data show a 2.5-fold increase of FSH, a 10.7-fold increase of LH, and a consequent decrease in the FSH: LH ratio from 5 to 1 between childhood and adulthood. FSH and LH in urine from three patients with gonadal abnormalities have also been studied. The results from normal children, adults, and abnormal patients form a spectrum and reveal that sexual maturity is accompanied by a marked increase in the excretion of LH with relatively smaller increases in FSH.
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Extracts containing uridine diphosphate (UDP) glucose dehydrogenase (EC 1.1.1.22) activity were prepared from 5 normal human synovial cell lines and sources of variation in the method determined. The mean catalytic activity of UDP-glucose dehydrogenase from the 5 extracts was 12.0 +/- 2.4 x 10(-3) International Units/mg protein. The KmUDP-glucose was estimated as 3.90 +/- 1.56 x 10(-5) M and the KmNAD+ was estimated as 1.72 +/- 0.60 x 10(-4) M. Maximum catalytic activity occurred in a temperature range of 55 degrees C-68 degrees C and in a pH range of 8.1-8.4. The mechanistic implications of these data in the normal human diarthrodial joint are discussed.
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Extracts containing uridine diphosphate (UDP) glucose dehydrogenase (EC 1.1.1.22) activity were prepared from rheumatoid and from normal human synovial cell lines using previously standardized techniques. Although no significant differences in the enzyme from the 2 sources were detected with respect to activity, substrate affinities, or responses to temperature and pH, these determinations have demonstrated that the enzyme is very sensitive to alterations in these parameters. The ultimate activity of the enzyme in vivo will be dependent upon the extent of the increased temperature, acidity, and altered glucose metabolism in the rheumatoid joint.