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Pulsatile Glycoprotein Hormone Secretion in Glycoprotein-Producing Pituitary Tumors^*

Division of Endocrinology, University of Texas Health Sciences Center San Antonio, Texas 78284–7877
the Divisions of Endocrinology and Metabolis University of Colorado Health Sciences Center Denver, Colorado 80262
Neuropathology University of Colorado Health Sciences Center Denver, Colorado 80262
Neurosurgery University of Colorado Health Sciences Center Denver, Colorado 80262

Address requests for reprints to: Dr. M. H. Samuels, Department of Medicine, Division of Endocrinology, University of Texas Health Sciences Center, 7703 Floyd Curl Drive, San Antonio, Texas 78284-7877.

To study patterns of hormone production and secretion in glycoprotein-producing pituitary tumors, 12 patients with such tumors underwent the following studies. Preoperatively, all patients had serum TSH, LH, FSH, and -subunit levels measured every 15 min for 24 h. Hormone pulses were located by cluster analysis, and pulse parameters were compared to those in healthy young men, healthy young women, healthy postmenopausal women, and subjects with primary hypothyroidism. After surgery, immunocytochemistry for the four glycoproteins was performed on all tumors, and Northern blot analysis was performed in six tumors with probes for the four subunits. By immunocytochemistry, 42% of the tumors were positive for TSHβ, 83% for LHβ 75% for FSHβ, and 92% for -subunit. Preoperative serum hormone levels varied widely between patients and were not well correlated with the intensity of immunocytochemical staining. Northern blot analysis did not appear to be as sensitive as immunocytochemistry for detection of the glycoproteins. All patients had pulsatile glycoprotein secretion, with pulses of normal frequency but varied amplitude. These results suggest that in patients with glycoprotein tumors, hormone pulses may be an integral part of autonomous secretion, or that hypothalamic control is involved in glycoprotein secretion and, perhaps, in the pathogenesis of these tumors.

^* This work was supported in part by Adult GCRC Grant MOl–RR–00051 and NIH Grants DK–36843–03 (to M.H.S.) and CA–47411–01 and DK–36843 (to E.C.R.).

Received January 7, 1991.