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Brown-Grant
The distribution of radioiodide in the genital tract of the ewe.Hovell GJ, Cullen R, Brown-Grant K. J Reprod Fertil. 1973 Sep;34(3):535-7. [citation only]
The sites of iodide concentration in the oviduct and the uterus of the rat.Brown-Grant K, Rogers AW. J Endocrinol. 1972 Jun;53(3):355-62.
"Previous studies have shown that under the influence of progesterone the concentrations of radioiodide in the uterus and oviduct of the rat are maintained at levels higher than that in the plasma. In the present experiments the uterus and oviducts from rats killed 2 h. after the injection of Na-125I were autoradiographed by a technique which permits the localization of diffusible radioactive material. Intact non-pregnant rats and ovariectomized rats not injected with progesterone, uniformly low grain densities were observed over sections of oviduct and uterus with the exception of the epithelium and lumen of the oviduct where some increase in grain density was observed. In intact and ovariectomized rats treated with progesterone and in rats killed on Day 3 or 4 of pregnancy, grain densities over the epithelium and lumen of the oviduct were very high but the fimbria of the oviduct were consistently unlabelled. The stroma underlying the oviduct epithelium was also labelled. In the uteri of these animals the principal site of concentration of radioiodide was the luminal epithelium, but for technical reasons it was not possible to exclude the stroma immediately adjacent to the luminal epithelium as a less active site of concentration of iodide. No other site in the uterus concentrated radioiodide. The luminal epithelium occupies less than 3% of the volume of the uterus in ovariectomized rats; if this tissue is taken as the sole site of iodide concentration in the uterus, the levels reached in these cells must be at least a hundred times that of the plasma when the overall uterus:plasma concentration ratio for radioiodide is 4 or more."
Analysis of the effects of progesterone on the synthesis of RNA and protein in the uterus of the ovariectomized rat and on the development of an iodide concentrating mechanism.Brown-Grant K, John PN, Rogers AW. J Endocrinol. 1972 Jun;53(3):363-74. [citation only]
The effects of castration on the ultrastructure and the iodide-concentrating ability of mouse submaxillary salivary glands.Rogers AW, Brown-Grant K J Anat. 1971 May;109(Pt 1):51-62.
"Previous studies have shown that the submaxillary gland of castrated male mice concentrate inorganic iodide to higher level than those of control males. Glands from both groups of mice have been autoradiographed following an injection of [125-I]-iodide, using a technique that permits the localization of diffusible material. In both groups, iodide was concentrated in the cytoplasm of cells of the convoluted granular tubules (CGT). Lower levels of concentration were also seen in the epithelium of the interlobular ducts and in their luminal contents.
"Cells of the CGT of normal males contained abundant rough endoplasmic reticulum (RER) with many dilated cisternae, and apical secretion granules. Infoldings of the basal cell membrane, with many associated mitochondria, were seen. Following castration, cells of the CGT were smaller: the RER largely disappeared. The infoldings of the basal cell membrane, with their associated mitochondria, formed a conspicuous array visible as basal striations under the light microscope.
"These findings are consistent with the hypothesis that active transport of iodide is a function of the cell membrane, which produces a high concentration of this ion in the cytoplasm. Castration eliminates from the cells the cisternae of RER, reducing the volume of the CGT and of the whole gland, without reducing the volume of the cytoplasmic compartment within which the iodide ion is concentrated."
Early effects of progesterone on the uterus of the ovariectomized rat.Rogers AW, John PN, Brown-Grant K. J Anat. 1970 Jan;106(Pt 1):182-3. [citation only]
Further studies of the metabolism of thyroxine and 3,5,3'-triiodothyronine in the guinea-pig.Brown-Grant K. J Physiol. 1967 Jul;191(1):167-76.
"1. Thyroxine labelled with 125I and triiodothyronine labelled with 131I have been administered simultaneously to guinea-pigs and their metabolism studied by whole body counting and measurement of radioactivity in urine, faeces, and blood. 2. The half-life of triiodothyronine in the body is about 19 hr, significantly less than that of thyroxine (41 hr). 3. After triiodothyronine administration, an unidentified iodinated compound appears in the blood which complicates the estimation of the half-life of this hormone by measurement of the radioactivity in peripheral blood. 4. A previous report, based on measurements of blood radioactivity, that the half-lives of the two hormones are similar in the guinea-pig was not confirmed.
A quantitative study of the effects of progesterone and related steroids on the uterus:plasma concentration ratio for radioactive iodide in the rat.Brown-Grant K J Endocrinol. 1967 Jun;38(2):145-61. [citation only]
The effects of a single injection of progesterone on the oestrous cycle, thyroid gland activity and uterus-plasma concentration ratio for radio-iodide in the rat.Brown-Grant K. J Physiol. 1967 May;190(1):101-21.
"1. A single subcutaneous injection of 5 mg, 1·25 mg or 625 μg, but not 312 μg, of progesterone in oil delayed ovulation in the rat by 1 or more days, when injected at the dioestrous stage of a 4-day oestrous cycle. 2. When ovulation was delayed in this way the expected increase in the thyroid-serum concentration ratio for 131I was also delayed but the ratio did increase when delayed ovulation occurred. 3. A single injection of progesterone resulted in an increase in the uterus-plasma and oviduct-plasma concentration ratios for 131I; the increase was greatest when steroid was injected at the dioestrous stage of the cycle and was delayed and least when the steroid was given at the pro-oestrous stage. 4. Ovulation was advanced by 1 day when progesterone was injected on the second day of dioestrus in rats showing regular 5-day cycles; this ovulation was not accompanied by an increase in the thyroid-serum concentration ratio. In these experiments a dose of progesterone that failed to advance ovulation produced a rise in uterus-plasma and oviduct-plasma ratio for 131I but no rise was seen when ovulation was induced, suggesting that oestrogen secretion had been stimulated. 5. 20α-Dihydroprogesterone (pregn-4-en-20α-o1-3-one) was not effective in delaying or advancing ovulation at a dose level of 2·5 mg per rat and had no effect on the uterus-plasma concentration ratio for radio-iodide. 6. These results are discussed in relation to the hypothesis that the increase in thyroid gland activity at the oestrous stage of the cycle is related to the neuro-endocrine changes that lead to ovulation.
The sites of concentration of radioiodide in the oviduct and uterus of the ovariectomized rat, under the influence of progesterone.Brown-Grant K, Rogers AW J Anat 1967. 101, pp 622-623 (Abstr) [citation only]
Concentration of radioiodide by the uterus of the rat and the relationship to blastocyst implantationBrown-Grant K J Physiol. 1966 May;184(2):418-32.
"1. When pregnant rats are ovariectomized early in pregnancy and treated with progesterone a raised uterus—plasma concentration ratio (U/P ratio) for radio-iodide is observed at the usual stage of pregnancy (days 3, 4 and 5) but is not followed by implantation. When delayed implantation is induced by the administration of oestradiol it is not preceded by a rise in the U/P ratio for 131I. 2. Similar findings are obtained when implantation is delayed by concurrent lactation in rats mated at the post-partum oestrus. 3. Ovariectomy early in pregnancy without progesterone treatment prevents the rise in U/P and oviduct—plasma (O/P) ratio for 131I that normally occurs. 4. Administration of progesterone to intact or ovariectomized non-pregnant rats produces a raised U/P and O/P ratio for 131I; oestrogen may inhibit this response. The simplest explanation of these results is a direct action of progesterone on the uterus. 5. By gross dissection it was possible to show that the region of high iodide concentration in the rat uterus is the endometrium. 6. No evidence of a concentration of iodide in the uterus or oviduct of the pregnant rabbit was obtained."
The secretion of radioactive iodide by the stomach of the anaesthetized dog in relation to total gastric blood flow and to acid secretion.Brown-Grant K, Summing JS, Haigh AL, Harries EH J Physiol. 1965 Apr;177:337-45.
"1. The gastric clearance of radioactive iodide,
acid secretion and total gastric blood flow have been measured in
anaesthetized dogs. 3. The effects of adrenaline and noradrenaline infusions on histamine-induced acid and iodide secretion were in general the same but the extent to which the two processes were affected was not usually the same. 4. 5-Hydroxytryptamine stimulated iodide secretion by the stomach, producing a small volume of secretion of very high iodide concentration relative to the blood; no effect on acid secretion was observed. No consistent effects of 5-hydroxytryptamine on histamine-induced acid or iodide secretion were observed. 5. These findings support the view that iodide and acid secretion are separate and distinct processes. 6. During vigorous histamine-induced secretion the fraction of the total gastric blood flow passing through the mucosal capillaries must be at least 0.3-0.4.
The metabolism of iodide by the thyroid gland and by the uterus during early pregnancy in the rat.Brown-Grant K J Physiol. 1965 Jan;176:73-90.
"1. Thyroidal uptake of radio-iodide, thyroid serum ratios for 131-I and the rate of release of 131-I from the thyroid have been measured during early pregnancy and pseudopregnancy in the rat. 2. No evidence was obtained of any increase in the secretion of pituitary TSH between Days 2 and 3 of pregnancy at the time of the postulated LH release concerned with implantation or of a persistence during pregnancy of the periodic increase in TSH release associated with cyclic ovulation. Thyroid activity is moderately depressed during early pregnancy and pseudopregnancy. 3. Concentration of iodide by the uterus has been demonstrated during Days 3 and 4 of pregnancy and pseudopregnancy in rats and Days 2 and 3 of pregnancy of mice. 4. The oviduct of rats is able to concentrate iodide. This is detectable during the metoestrus and dioestrus stages of the cycle and during early pregnancy or pseudopregnancy. 5. The possible significance of iodide concentration by the uterus and oviduct is discussed."
Failure to demonstrate a concentration of iodide by the submandibular gland of the rat.Brown-Grant K J Physiol. 1963 Mar;165:519-27.
"1. The submandibular gland of the rat does not concentrate iodide in vivo or in vitro. 2. Alterations in gland structure induced by hypothyroidism, castration or large doses of iso-propylnoradrenaline do not result in iodide concentration. 3. Organic binding of iodine by gland slices incubated in a simple saline medium has been demonstrated."
The relation between structure and the concentration of iodide by the submandibular glands of mice and hamsters.Brown-Grant K, Taylor W J Physiol. 1963 Mar;165:508-18.
"1. The gland/blood ratio in vivo and the tissue/medium ratio in vitro for 1311-iodide is higher for the submandibular glands of male than those of female mice. 2. Glands from hypothyroid or castrate male mice show higher ratios than those from normal controls, although the convoluted granular tubules are histologically atrophic. 3. The glands of young mice and hamsters concentrate iodide in vivo before the convoluted granular tubules develop. 4. It is suggested that these ratios measure the iodide-concentrating capacity of the glands and that this capacity is retained or even enhanced in the histologically atrophic tubule."
The distribution of radio-iodide in the skin of the rat.Brown-Grant K, Pethes G, Rogers AW J Physiol. 1960 Jul;152:467-73
1. The existence of a skin:blood concentration ratio for 131-I greater than 1.0: 1 in the first few hours after injection in suckling and adult rats has been confirmed. 2. Measurements of the l31-I content of macroscopic horizontal sections of frozen skin have shown that the highest concentration occurs in the outer epidermal layer and that 131-l is preferentially discharged from this region by thiocyanate. 3. Autoradiographic studies have shown that the 131-I that can be discharged by thiocyanate is located in the lower layers of the epidermis. A concentration of 131-I in the region of the hair follicles has also been observed. 4. Some possible explanations for the existence of an iodide concentrating mechanism in the epidermis of the rat are discussed briefly."
Concentration of radio-iodide in the skin of the rat.Brown-Grant K, Pethes G J Physiol. 1959 Oct;148:683-93.
" 1. After injection of radio-iodide into suckling and adult rats a high percentage of the dose can be recovered from the skin in the first few hours. 2. The radioactivity of the skin at this time is due to the presence of radioiodide in equilibrium with the blood; the uptake can be reduced or iodide already present can be discharged by administering KSCN. 3. The high skin: blood ratios (2-0-5.0) observed, and the results of thiocyanate administration, suggest that an active concentrating mechanism is involved. 4. No concentration was observed in the skin of the mouse or the guinea pig and thiocyanate had no effect on skin content of 131-I in these species. 5. The initially high skin content of 131-I falls rapidly in the adult and slowly in the suckling until about 3% of the injected dose is present in the skin at 24 hr in the adult and at 260 hr in the suckling. This residual radio-iodide is present in the hair. 6. Some implications of these findings are discussed."
Iodinated compounds in milk after radio-iodide administration.Brown-Grant K, Galton VA Biochim Biophys Acta. 1958 Feb;27(2):422-3. [citation only]
The iodide concentrating mechanism of the mammary gland.Brown-Grant K J Physiol. 1957 Mar 11;135(3):644-54.
"1. The milk/plasma ratio for 131I has been studied for periods up to 6 hr after injection in anaesthetized rabbits and values between 6.7 and 37.4 were found. Methylthiouracil had no effect on the establishment of a high M/P ratio. 2. The M/P ratio was depressed by various anions, the order of potency being: ClO4- > SCN- >/= I- > IO3 > NO3 > BrO3-. Bromide and chloride had no effect. 3. A concentration gradient for 131I between milk and plasma was also found in guinea-pigs, rats and mice and was shown to be reduced by thiocyanate. 4. No evidence was obtained for the concentration of thiocyanate in the milk during inhibition of iodide concentration by this anion. 5. A small proportion (up to 5%) of the radio-iodine found in rabbit's milk appears to be in organic combination. This fraction is not seen after methylthiouracil administration. 6. The iodide metabolism of the mammary gland is discussed and compared with that of the thyroid and other extra-thyroidal iodide concentrating tissues.
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