Regarding the validity of the endpoint response of the mouse (McKenzie) bioassay for thyrotrophin (TSH)

1981 ◽  
Vol 96 (3) ◽  
pp. 342-349 ◽  
Author(s):  
Melvin Ching

Abstract. The release of radiolabelled thyroid hormone into the circulation in low iodine fed mice has been used extensively as a bioassay for thyroid stimulating hormone (TSH). However, the specificity of several bioassays of pituitary hormones have been subject to question. Consequently, the validity of the assay endpoint for TSH in the mouse was re-evaluated with respect to the effect of luteinizing hormone (LH) whose chemical composition closely resembles that of TSH. Mice, prepared for bioassay of TSH received injections of purified LH or α or β subunits of LH. Identical doses of LH and LH subunits were quantified by LH and TSH radioimmunoassays and the results compared with those obtained by the bioassay. Microgram quantities of LH and subunits of LH elicited appreciable responses in the TSH bioassay but produced only negligible effects in the TSH radioimmunoassay. The response of the TSH bioassay of LH and α or β subunits of LH was 40–56% that obtained with LH radioimmunoassay. However, the pituitary concentrations obtained by TSH bioassay when compared with those obtained by radioimmunoassays for TSH, LH, or growth hormone (GH) paralleled closely the TSH radioimmunoassay data, although in terms of quantitative estimates, there was a 15-fold discrepancy between the TSH assays. Estimations of pituitary concentrations of LH lead to the conclusion that, at the doses normally employed, most crude rat pituitary extracts do not contain sufficient quantities of LH to alter significantly bioassayable (McKenzie) estimates of TSH.

Author(s):  
Mone Zaidi ◽  
Li Sun ◽  
Peng Liu ◽  
Terry F. Davies ◽  
Maria New ◽  
...  

AbstractPituitary hormones have traditionally been thought to exert specific, but limited function on target tissues. More recently, the discovery of these hormones and their receptors in organs such as the skeleton suggests that pituitary hormones have more ubiquitous functions. Here, we discuss the interaction of growth hormone (GH), follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), prolactin, oxytocin and arginine vasopressin (AVP) with bone. The direct skeletal action of pituitary hormones therefore provides new insights and therapeutic opportunities for metabolic bone diseases, prominently osteoporosis.


1976 ◽  
Vol 24 (2) ◽  
pp. 448-452 ◽  
Author(s):  
G T Campbell ◽  
A S Bhatnagar

Two indirect methods involving enzyme-labeled antibodies were used to demonstrate simultaneously two distinct tissue antigens in the same histologic section without a need for antigen-antibody dissociative procedures. Sections of rat pituitary gland were incubated with rabbit anti-rat luteinizing hormone followed by goat anti-rabbit gamma-globulin conjugated to horseradish peroxidase. The same sections were then further incubated with monkey anti-rat growth hormone followed by goat anti-monkey gamma-globulin conjugated to glucose oxidase. Antigenic luteinizing hormone was subsequently localized with hydrogen peroxide-3,3'-diaminobenzidine as substrate for peroxidase, and growth hormone was localized with a glucose-phenazine methosulfate-nitroblue tetrazolium mixture as a substrate for glucose oxidase. The method relies on the availability of specific primary antibodies raised in different animal species in addition to corresponding specific secondary antibodies linked covalently to separate enzymes.


1974 ◽  
Vol 61 (1) ◽  
pp. 15-19 ◽  
Author(s):  
MELVIN CHING

SUMMARY The tadpole, in metamorphic stasis, has been used as a bioassay recipient for thyroid-stimulating hormone (TSH). The validity of its use for this purpose, however, has not been tested critically, particularly with respect to the effect of other hormones, most notably, growth hormone (GH) and luteinizing hormone (LH). Growth hormone has been shown to influence thyroid function and LH is a common contaminant of pituitary TSH preparations. Tadpoles of Rana pipiens, arrested at a particular metamorphic stage, received various concentrations of LH alone, a combination of doses of GH and TSH, or GH and rat anterior pituitary extract. Growth hormone was ineffective in re-inducing metamorphosis in 78% of cases, whereas LH stimulated metamorphosis in the tadpoles.


1965 ◽  
Vol 32 (2) ◽  
pp. 205-214 ◽  
Author(s):  
S. A. GUNN ◽  
THELMA C. GOULD ◽  
W. A. D. ANDERSON

SUMMARY Five pituitary hormones: follicle-stimulating hormone (FSH), adrenocorticotrophic hormone (ACTH), thyroid-stimulating hormone (TSH), growth hormone and prolactin, were tested for their capacity to alter the control by interstitial cell-stimulating hormone (ICSH) of the uptake of 65Zn by the dorsolateral prostate gland of the mature hypophysectomized Sprague-Dawley rat. Only prolactin and growth hormone produced significant augmentation of the response to ICSH. Contamination with growth hormone was apparently not responsible for the augmentation of ICSH activity brought about by the NIH-prolactin preparation used. NIH-prolactin and a highly purified preparation provided by Dr C. H. Li were shown to be equally effective in their capacity to augment the 65Zn-uptake response produced by ICSH. Augmentation was detectable with total doses of prolactin as low as 10–30 μg. (0·21–0·63 i.u.). Prolactin caused an augmentation of testosterone activity on uptake of 65Zn in the hypophysectomized and castrated rat, indicating an effect of prolactin on the prostate that is not mediated by the testis. NIH-growth hormone was not as effective as the prolactin preparations in enhancing ICSH activity, but in sufficient doses produced a significant increase in the 65Zn-uptake response to ICSH. These studies showed also that the uptake of 65Zn of the dorsolateral prostate was a more sensitive and more consistent parameter than glandular weight for the detection of augmentation of ICSH response by growth hormone or prolactin preparations.


1970 ◽  
Vol 63 (2) ◽  
pp. 378-384 ◽  
Author(s):  
D. R. Hodges ◽  
W. H. McShan

ABSTRACT Electrophoretic analyses of rat, mouse, human and cow anterior pituitary homogenates with subsequent bioassays for hormonal activity have been reported. Comparison of the behaviour of the hormonal activities from rat anterior pituitary secretory granules and that reported for pituitary homogenates was made following disc electrophoresis on polyacrylamide gels. Bioassays of gel segments for the six anterior pituitary hormones resulted in the localization of the activities of five of the six hormones. ACTH activity was not detected. Growth hormone and prolactin were associated with the major cathodal and anodal discs respectively. Luteinizing hormone and thyroid stimulating hormone activities had similar mobilities and were located in a zone just above growth hormone. The activity was not restricted to a discrete, stainable disc in either case. Follicle stimulating hormone activity was detected in a narrow segment containing only one disc a few millimeters below growth hormone. Comparison of the mobilities of the hormones from homogenates and secretory granule extracts suggests that they have essentially similar electrophoretic characteristics at basis pH.


1975 ◽  
Vol 53 (6) ◽  
pp. 1094-1098 ◽  
Author(s):  
G. Queen ◽  
S. Vivian ◽  
F. LaBella

Cells were dispersed from bovine anterior pituitary glands, by digestion with collagenase, and cultured. After 4 days the cell monolayers were incubated with fresh medium containing synthetic hypophysiotropic peptides for 2, 6, or 20 h, and hormone released into the medium was estimated by radioimmunoassay. After 2 h, thyroid releasing hormone (TRH) stimulated the release of thyroid-stimulating hormone (TSH) up to eightfold, and of prolactin (PRL) and follicle-stimulating hormone (FSH) about twofold at a minimal effective concentration of 1 ng/ml; enhanced growth hormone (GH) release was not apparent until 20 h, and release of luteinizing hormone (LH) and adrenocorticotrophic hormone (ACTH) was unaffected. Luteinizing hormone releasing hormone (LH-RH) enhanced release of LH maximally (three- to fourfold) during a 2 h incubation and was effective at 0.1 ng/ml; FSH release was significantly enhanced by about 50% above control level. Growth hormone release inhibiting hormone (GH-RIH) (somatostatin) showed significant effects only in the 20 h incubation; GH release was inhibited by 50% and release of PRL was slightly, but significantly, enhanced. Pituitary cell monolayers apparently permit maximal expression of releasing activities inherent in the hypothalamic hormones.


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