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J. B. BROWN, CAROLINE MACNAUGHTAN, MARGERY A. SMITH and BARBARA SMYTH

SUMMARY

Higher temperatures allow lower sulphuric acid concentrations and shorter heating times to be used in the Kober colour reaction for oestrogens. A one-stage reaction which is completed in 5 min. at 120° is described for oestrone and oestradiol, and a two-stage reaction which requires two periods of heating for 5 min. at 120° is described for oestriol. The conditions were applied to the Ittrich fluorescence procedure. A spectrophotofluorimetric correction was developed in which fluorescence was measured at wavelengths for excitation and emitted light near the optima for the oestrogens and at another combination at which the oestrogens produced virtually no fluorescence whereas that of impurities was not diminished. Extraction, centrifugation and fluorimetry were performed in specially designed cells. The sensitivity is 0·05–0·1 ng./sample with a linear response up to 300 ng. and a precision better than 4% in the range 1·0–100 ng.

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N. W. MOORE, SUSAN BARRETT, J. B. BROWN, IRENE SCHINDLER, MARGERY A. SMITH and BARBARA SMYTH

SUMMARY

Ovarian vein blood was collected by cannulating the ovarian vein of 37 ewes at various times during the oestrous cycle. Plasma progesterone and oestrogen concentrations, determined by chemical methods, showed marked cyclic variations during the cycle. Progesterone was detected at all stages of the cycle. Plasma concentrations were rising rapidly by the 4th day after the onset of oestrus and were maintained at levels greater than 100 μg./100 ml. plasma from the 8th to the 14th day of the cycle. They started to fall about 48 hr. before the onset of oestrus. Very low levels, of the order of 1 μg./100 ml. plasma, were maintained from 24 hr. before to 8–16 hr. after the onset of oestrus.

Oestradiol-17β made up almost all of the oestrogens measured. Oestrone accounted for less than one-eighth of the total oestrogens. Oestradiol first appeared on the 14th day of the cycle and its concentration rose rapidly during the immediate pre-oestrous period to reach peak levels of over 100 ng./100 ml. plasma 20–30 hr. before the onset of oestrus. They then rapidly declined and by 24 hr. after the onset had reached almost non-detectable levels.

The ovarian secretion rate of progesterone was calculated to be 3·5 mg./day at mid-cycle and the total secretion of oestradiol during the follicular phase was 4·9 μg. Blood flow through the cannula was not affected by either the stage of cycle at which blood was collected or by the structure (corpus luteum or Graafian follicle) in the ovary bled.

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J. B. BROWN, S. C. MacLEOD, CAROLINE MACNAUGHTAN, MARGERY A. SMITH and BARBARA SMYTH

SUMMARY

A semi-automatic extractor was developed which processes 12 urines at a time to a stage where 'total' oestrogens can be measured by colorimetry using the Kober reaction (late pregnancy urines) or by fluorimetry using the Kober—Ittrich procedure (non-pregnancy and early pregnancy urines). One worker can complete 12 analyses in 3½ hr. or 24–36 in a working day. The results obtained at oestrogen levels above 1 mg./24-hr. urine were the same as those obtained by a method specific for oestriol. The results obtained from non-pregnancy urines were compared with the sums of oestriol, oestrone and oestradiol obtained by the method of Brown (1955). The mean ratio (± s.d.) of the two values was 1·22 ± 0·31. The comparisons indicated that the short procedure was the more reliable method at levels below 5 μg./24-hr. urine. Values for normal subjects are given. The methods appear to be entirely suitable for assessing oestrogen production by the ovaries, testes, adrenals and placenta.