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J G Ratcliffe

Publications and source records attributed to J G Ratcliffe.

At least 163 records · Page 9Linked to original sources
PubMed1974

A critical evaluation of separation methods in radiommunoassay for total triiodothyronine and thyroxine in unextracted human serum.

Methods for separating free and antibody-bound hormone in radioimmunoassays for total triiodothyronine (T-3) and thyroxine (T-4) in unextracted human serum are evaluated. For T-3 assay, a simplified second antibody technique has significant advantages over other methods and gives a mean interassay coefficient of variation of 7.2% over a wide range of values. For T-4 assay, polyethylene glycol is the method of choice and has a mean interassay coefficent of variation of 4.7%. By adding the separating agents initially, the assays are readily semi-automated and may be completed within a working day.

Analysis of Variance↗
PubMed1973

Pituitary peptide.

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Adrenocorticotropic Hormone↗
PubMed1973

Comparison of corticotrophin and corticosteroid response to lysine vasopressin, insulin, and pyrogen in man.

Plasma corticotrophin (ACTH) and corticosteroid levels in response to lysine vasopressin (LVP), insulin hypoglycaemia, and pyrogen have been compared in seven subjects with normal pituitary adrenal function. Intramuscular vasopressin was a weak stimulus to corticotrophin release, peak values lying within the range 49 to 141 pg/ml. Insulin hypoglycaemia consistently caused a more noticeable increase, with peak levels between 114 and 364 pg/ml, while pyrogen was the most powerful, corticotrophin levels rising to between 209 and 1,725 pg/ml. Peak plasma corticosteroid levels showed less pronounced differences between the three tests, and correlated poorly with peak ACTH levels. Thus, relatively small acute changes in corticotrophin levels produce near-maximal adrenal stimulation. Under these conditions, plasma corticosteroid measurements do not accurately reflect circulating corticotrophin levels. These findings help to explain the physiological basis of several observations on the corticosteroid responses to these clinical test procedures.

11-Hydroxycorticosteroids↗