Abstract
Synthetic thyrotropin-releasing hormone (TRH) was administered to normal children and hypopituitary patients in a dose of 7 μg/kg i.v. over 30-60 sec. Serum thyrotropin (TSH) and prolactin (HPr) concentrations were measured by radioimmunoassay before and at 15-min intervals for 2 hr after TRH. In 20 normal children HPr rose from a mean baseline value of 7.0±1.2 (SEM) ng/ml to a mean peak value of 39.5±5 ng/ml.
In 11 patients with growth hormone (GH) deficiency without TSH deficiency. HPr values rose from a mean baseline of 3.6±0.8 ng/ml to a mean peak value of 13.9±2.8, a significantly less peak response as compared with normal children (P < 0.005). The TSH responses to TRH, however, were statistically indistinguishable from those of normal children.
In 10 patients with GH and TSH deficiency both the mean baseline HPr levels (25.0±5 ng/ml) and the mean peak HPr levels after TRH (68.5±10 ng/ml) were significantly higher (P < 0.005 and < 0.025) than those of normal children. Similar comparisons were also true for the peak TSH responses (P < 0.05). Two panhypopituitary patients released no TSH and only small amounts of HPr after TRH. After thyroid replacement therapy in eight of the patients with GH and TSH deficiency, the mean HPr baseline levels (7.6±1.0 ng/ml) and peak levels (23.3±4.6 ng/ml) after the same dose of TRH were significantly less than their pretreatment levels (P < 0.001 and < 0.01) and were within the range for normal children.
Synthetic TRH stimulates the simultaneous release of TSH and HPr in normal children and most hypopituitary patients. When the concentrations of thyroxine (T4) and triiodothyronine (T3) are low, the levels of HPr before and after TRH are elevated. After thyroid replacement therapy, HPr levels decrease to normal. T4 and/or T3 may condition the production or effects of prolactin-inhibiting factor (PIF) activity. The TSH and HPr responses after TRH in hypopituitary patients will determine whether the primary defect resides in the pituitary or hypothalamus, but cannot delineate the hypothalamic defect as a deficiency of hypothalamic hormone production or neurohumoral transmission.
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- Anderson M. S., Bowers C. Y., Kastin A. J., Schalch D. S., Schally A. V., Snyder P. J., Utiger R. D., Wilber J. F., Wise A. J. Synthetic thyrotropin-releasing hormone. A potent stimulator of thyrotropin secretion in man. N Engl J Med. 1971 Dec 2;285(23):1279–1283. doi: 10.1056/NEJM197112022852302. [DOI] [PubMed] [Google Scholar]
- Bowers C. Y., Friesen H. G., Hwang P., Guyda H. J., Folkers K. Prolactin and thyrotropin release in man by synthetic pyroglutamyl-histidyl-prolinamide. Biochem Biophys Res Commun. 1971 Nov;45(4):1033–1041. doi: 10.1016/0006-291x(71)90441-4. [DOI] [PubMed] [Google Scholar]
- Bowers C. Y., Schally A. V., Schalch D. S., Gual C., Kastin A. J., Folkers K. Activity and specificity of synthetic thyrotropin-releasing hormone in man. Biochem Biophys Res Commun. 1970 May 11;39(3):352–355. doi: 10.1016/0006-291x(70)90583-8. [DOI] [PubMed] [Google Scholar]
- Costom B. H., Grumbach M. M., Kaplan S. L. Effect of thyrotropin-releasing factor on serum thyroid-stimulating hormone. An approach to distinguishing hypothalamic from pituitary forms of idiopathic hypopituitary dwarfism. J Clin Invest. 1971 Oct;50(10):2219–2225. doi: 10.1172/JCI106717. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fleischer N., Burgus R., Vale W., Dunn T., Guillemin R. Preliminary observations on the effect of synthetic thyrotropin releasing factor on plasma thyrotropin levels in man. J Clin Endocrinol Metab. 1970 Jul;31(1):109–112. doi: 10.1210/jcem-31-1-109. [DOI] [PubMed] [Google Scholar]
- Foley T. P., Jr, Owings J., Hayford J. T., Blizzard R. M. Serum thyrotropin responses to synthetic thyrotropin-releasing hormone in normal children and hypopituitary patients. A new test to distinguish primary releasing hormone deficiency from primary pituitary hormone deficiency. J Clin Invest. 1972 Feb;51(2):431–437. doi: 10.1172/JCI106829. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Greenberg A. H., Czernichow P., Hung W., Shelley W., Winship T., Blizzard R. M. Juvenile chronic lymphocytic thyroiditis: clinical, laboratory and histological correlations. J Clin Endocrinol Metab. 1970 Mar;30(3):293–301. doi: 10.1210/jcem-30-3-293. [DOI] [PubMed] [Google Scholar]
- Hall R., Amos J., Garry R., Buxton R. L. Thyroid-stimulating hormone response to synthetic thyrotrophin releasing hormone in man. Br Med J. 1970 May 2;2(5704):274–277. doi: 10.1136/bmj.2.5704.274. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hershman J. M., Pittman J. A., Jr Response to synthetic thyrotropin-releasing hormone in man. J Clin Endocrinol Metab. 1970 Oct;31(4):457–460. doi: 10.1210/jcem-31-4-457. [DOI] [PubMed] [Google Scholar]
- Hershman J. M., Pittman J. A., Jr Utility of the radioimmunoassay of serum thyrotrophin in man. Ann Intern Med. 1971 Apr;74(4):481–490. doi: 10.7326/0003-4819-74-4-481. [DOI] [PubMed] [Google Scholar]
- Jacobs L. S., Mariz I. K., Daughaday W. H. A mixed heterologous radioimmunoassay for human prolactin. J Clin Endocrinol Metab. 1972 Mar;34(3):484–490. doi: 10.1210/jcem-34-3-484. [DOI] [PubMed] [Google Scholar]
- Jacobs L. S., Snyder P. J., Wilber J. F., Utiger R. D., Daughaday W. H. Increased serum prolactin after administration of synthetic thyrotropin releasing hormone (TRH) in man. J Clin Endocrinol Metab. 1971 Dec;33(6):996–998. doi: 10.1210/jcem-33-6-996. [DOI] [PubMed] [Google Scholar]
- Ormston B. J., Cryer R. J., Garry R., Besser G. M., Hall R. Thyrotrophin-releasing hormone as a thyroid-function test. Lancet. 1971 Jul 3;2(7714):10–14. doi: 10.1016/s0140-6736(71)90005-5. [DOI] [PubMed] [Google Scholar]
- Penny R., Blizzard R. M., Davis W. T. Sequential arginine and insulin tolerance tests on the same day. J Clin Endocrinol Metab. 1969 Nov;29(11):1499–1501. doi: 10.1210/jcem-29-11-1499. [DOI] [PubMed] [Google Scholar]
- SCHALCH D. S., PARKER M. L. A SENSITIVE DOUBLE ANTIBODY IMMUNOASSAY FOR HUMAN GROWTH HORMONE IN PLASMA. Nature. 1964 Sep 12;203:1141–1142. doi: 10.1038/2031141a0. [DOI] [PubMed] [Google Scholar]
- Tashjian A. H., Jr, Barowsky N. J., Jensen D. K. Thyrotropin releasing hormone: direct evidence for stimulation of prolactin production by pituitary cells in culture. Biochem Biophys Res Commun. 1971 May 7;43(3):516–523. doi: 10.1016/0006-291x(71)90644-9. [DOI] [PubMed] [Google Scholar]