The measurement and experimental modification of thyroid activity in the rabbit

The thyroxine ‘receptor’ of the thyroid‐pituitary system

“…inhibition of thyroid release of radio-iodine from the thyroid for a period of 6-24 hr. This was probably due to the physical stress of operation and anaesthesia (BrownGrant, Harris & Reichlin, 1954 a). The experiments were carried out in the manner illustrated in Text-figures 2 and 3.…”

“…There is good evidence for the conclusion that the release of 131I from the thyroid is equivalent to secretion of labelled thyroid hormone (Albert, 1951;Perry, 1951;Wolf, 1951;Brown-Grant, Euler, Harris & Reichlin, 1954). Likewise it seems justified to assume that the secretion of the thyroid is governed solely by the thyrotropic hormone (TSH) of the anterior pituitary gland (cf.…”

The effects of partial hypophysectomy in the rabbit

“…Animals with pars distalis remnants below 10% of normal volume gave release curves of the 'flat slope' type ( Fig. 1 b) as obtained with the completelyhypophysectomized animal (Brown-Grant, von Euler et al 1954). Two rabbits in this latter group (Nos.…”

“…Brown-Grant, Harris & Reichlin (1954) have demonstrated that restraint diminishes the rate of radio-iodine release from the thyroid gland and that the normal rate is rapidly restored when the restraint is removed. This has been confirmed in eight experiments on eight animals.…”

“…After killing the animal, the bladder was removed and washed out, the washings being added to any urine in the flask under the diuresis cage. The measurement of the radioactive content of the thyroid, urine and plasma was performed by methods similar to those described by Brown-Grant, von Euler et al (1954). Determination of adrenal ascorbic acid content was done by the method described by Fortier et al (1957).…”