Suppression of Thyroid Function by Pituitary Tumor MtTW5

MacLeod, Robert M.; Bass, Mary B.; Buxton, Ernest P.; Dent, James Norman; Benson, Don G.

doi:10.1210/endo-78-2-267

Cited by 11 publications

(5 citation statements)

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“…Further, there is also an interaction of prolactin and thyroid hormone (Gelato, Marshall, Boudreau, Bruni, Campbell & Meites, 1975;Ottenweller & Hedge, 1980). Implants of the MtTW15 adenoma have been reported to cause hypothyroidism (Macleod, Bass, Buxton, Dent & Benson, 1966) and a decrease in thyroid hormone has been associated with a decreased ,-adrenergic response (Threatte, Barney, Baker & Fregly, 1983).…”

Section: Discussionmentioning

confidence: 99%

Effects of chronic hyperprolactinaemia on experimentally induced thirsts in male rats.

Katovich¹,

Simpkins²

1983

The Journal of Physiology

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SUMMARY1. Chronic hyperprolactinaemia was induced in ten male Wistar rats by subcutaneous injection of tissue fragments of the MtTW15 prolactin-secreting adenoma. Serum prolactin was elevated significantly by 3 weeks after adenoma inoculation and increased progressively thereafter.2. An additional ten Wister-Furth rats were innoculated with the MtTW15 adenoma and an equal number of age-matched controls were used to evaluate the drinking response to several dipsogenic agents.3. The hyperprolactinaemic rats consumed twice as much water as did control rats over a 24 hr period.4. Administration ofthekf-adrenergic agonist, isoprenaline (25 #ug/kg, s.c.), resulted in a similar increase in water intake in both groups prior to an elevation in serum prolactin. However, as serum prolactin increased there was a corresponding significantly attenuated dipsogenic response to isoprenaline.5. Chronic hyperprolactinaemia did not alter the drinking response to angiotensin II (200 jug/kg, s.c.), to 24 hr of dehydration or to administration of hypertonic (1 M) saline.6. These results indicate that chronic hyperprolactinaemia selectively attenuates the dipsogenic response to ,8-adrenergic stimulation and support an involvement of prolactin in modifying the responsiveness of the fl-adrenergic system.

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Section: Discussionmentioning

confidence: 99%

Effects of chronic hyperprolactinaemia on experimentally induced thirsts in male rats.

Katovich¹,

Simpkins²

1983

The Journal of Physiology

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“…The possibility of increased renal clearance of iodine decreasing the share of iodide trapped by the thyroid in the MtTW5-implanted rats has (been excluded, as the thyroid inhibition persists in nephrectomized tumor-bearing rats compared to nephrectomized controls ( 1 ) . The possibility of increased renal clearance of iodine decreasing the share of iodide trapped by the thyroid in the MtTW5-implanted rats has (been excluded, as the thyroid inhibition persists in nephrectomized tumor-bearing rats compared to nephrectomized controls ( 1 ) .…”

Section: )mentioning

confidence: 99%

“…After these are attained, the plasma concentration of the labeled enzyme declines ( 1). As a result, it takes about 3 hours after injection for the plasma amyla~e-'~lI to reach maximum values.…”

Section: Cedars-sinai Medical Research Institute Dfpartment Of Surgementioning

confidence: 99%

Thyroid Inhibition of Rats Bearing Transplantable, Hormone-Producing Pituitary Tumors

MacLeod

Abad

1968

Experimental Biology and Medicine

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Previous reports from this laboratory ( I ) have described the significantly reduced uptake of radioactive iodine, and the histology of an understimulated thyroid gland, present in rats implanted with hormone-secreting pituitary tumors. Thyroid inhibition also has been described in rats implanted with a malignant nonendocrine tumor (2,3) and in humans with a variety of cancers ( 4 ) .The tumor strain employed here was the MtTW5 which secretes prolactin and growth hormone but not TSH or ACTH. The hormonal properties of this tumor have been previously described (5,6). I t has been suggested that the thyroid inhibition of rats implanted with tumors ( 2 ) and of humans with cancers or chronic debilitating illnesses (7) is operated through nonspecific mechanisms such as a decrease in the thyroxine binding proteins, diminution which is just a participant in the generalized decrease of protein synthesis that goes on in those diseases. These possibilities were explored.Since thyroid suppression in the rats implanted with the pituitary tumors are not the result of the gland becoming unresponsive to TSH ( 1 ) , our attention was directed to the pituitary content of TSH and to some of the aspects of intrathyroid iodine metabolism that are affected by TSH. Materials and Methods. 1 ) Correlation of tumor size and thyroid inhibition of iodine uptake.Thirty-two adult \$%tar-Furth female rats were placed on regular Purina rat chow and tap water ad libitum. They were implanted S.C. in the right subscapular area with the MtTW5 tumor and were distributed in four cages containing eight rats each. On days 5, 8, 12,15, 20, 29, 36, 49 postimplantation, one rat from each cage was randomly selected, injected with 2 pC of carrier-free sodium ]:"I per 1 0 0 gm of body weight, and 18 hours later anesthetized with ether, and bled by cardiac puncture. Their thyroids and anterior pituitary glands were removed and weighed. One ml of serum and the thyroids suspended in 1 ml of saline were counted in a well scintillation counter.2 ) Levels of .free thyroxine ( T i ) in plasma were determined according to the equilibrium dialysis technique described by Ingbar et al. ( 8 ) . The serum extracted from one single rat was insufficient to carry out these studies on an individual basis, hence the serum from 2 4 rats was pooled.Control and tumor animals were matched by age and sex, but not by weight, because by virtue of the very same tumoral effects, the tumor-bearing rats were heavier.

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“…Implants of the Furth MtTWlS tumor have been reported to cause hypothyroidism (27,28). However, it has been reported that removal of the thyroid augments gonadotropin secretion in gonadectomized animals (29,30).…”

mentioning

confidence: 99%

“…It is likely that some neurotransmitter is involved in the suppression of LH secretion, because this tumor can also prevent growth hormone, TSH, and prolactin secretion by the in situ pituitary gland (27,28,31). Implants of the Furth MtTW15 tumor (32) or injections of prolactin (33) result in increased hypothalamic dopamine turnover, and increased dopamine turnover has been shown to reduce prolactin secretion by the in situ pituitary gland (31).…”

mentioning

confidence: 99%

Inhibition of Hypothalamic LHRH Depletion after Ovariectomy by Transplantable Prolactin and Growth-Hormone-Secreting Tumors

Hodson

Burden

Louis

et al. 1981

Experimental Biology and Medicine

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Anestrous Wistar-Furth rats bearing implants of the Furth MtTWlS tumor and diestrous tumor-free rats were ovariectomized and serum luteinizing hormone (LH), folliclestimulating hormone (FSH) concentrations, and hypothalamic luteinizing hormone-releasing hormone (LHRH) content, were studied. The increase of L H and FSH, after ovariectomy, was significantly greater in tumor-free rats than in rats bearing prolactin secreting tumor implants. The hypothalamic LHRH content of the intact tumor-bearing rats was greater (P < 0.01) than that of tumor-free rats. Furthermore, the depletion of hypothalamic LHRH content was greater in tumor-free rats than in tumor-bearing rats. These results suggest that this prolactin and growth-hormone-secreting tumor prevents gonadotropin release by reducing LHRH release from the hypothalamus. 369 0037-9727/81/070369-05$0 1 .OO/O

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Suppression of Thyroid Function by Pituitary Tumor MtTW5

Cited by 11 publications

References 0 publications

Effects of chronic hyperprolactinaemia on experimentally induced thirsts in male rats.

Effects of chronic hyperprolactinaemia on experimentally induced thirsts in male rats.

Thyroid Inhibition of Rats Bearing Transplantable, Hormone-Producing Pituitary Tumors

Inhibition of Hypothalamic LHRH Depletion after Ovariectomy by Transplantable Prolactin and Growth-Hormone-Secreting Tumors

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