Growth Hormone Concentration in Human Pituitary Tumours

Abstract

inspection of starch-gel electrophoresis patterns. Histological examination of the tumour tissue was performed on paraffin sections of formalin-fixed specimens after staining with haematoxylin and eosin, eosin and methyl blue, and PAS-orange G. Extracts of pituitary tissue were prepared by homogenization in tris-EDTA-boric acid buffer at pH 8\m=.\9.The clear supernatant obtained after centrifugation was subjected to radioimmunoassay and to starch-gel electrophoresis. Radioimmunoassay was performed by the solid-phase method (Catt, Niall & Tregear, 1967) using Wilhelmi HGH 705 A as the assay standard. Extracts were diluted to within the range of the assay (0-1-5 ng. HGH) and estimations based on the mean values obtained from two dilutions parallel to the standard curve. Electrophoresis was performed in a vertical tray holding five 0-3 ml. samples of extract in buried-origin slots, each equivalent to 50 mg. of the original fresh tissue. After electrophoresis at 280 for 5 hr., the gels were stained with amidoblack and nigrosine. The HGH content of each extract was assessed visually on a scale of 0 to 5 +, 5 + being equivalent to the main band in the normal pituitary pattern. This method is based on the demonstra¬ tion that HGH forms a major component of the electrophoretic pattern of human pituitary extracts (Ferguson & Wallace, 1963).The results (Table 1) show a general agreement between visual estimation and radioimmunoassay and a marked variation between the mean HGH concentrations in the normal anterior pituitary glands (23/ig./mg.), the tumours causing acromegaly (4-5/tg./mg.) and the non-functioning chromophobe tumours (0-012/tg./mg.). The tumours causing acromegaly did not include a purely eosinophilic tumour, which may be very rich in HGH (Young et al. 1965 ;Lloyd & Meares, 1965). The non-functioning chromophobe tumours, containing minute concentrations of HGH, showed occasional cells with light eosinophilic granulation. The 37-yr.-old acromegalie patient had

Radioimmunoassay of human growth hormone: technique and application to plasma, cerebrospinal fluid, and pituitary extracts

“…Our much smaller series of 18 cases did not show this correlation, possibly because it included five patients with pituitary fossa area within normal limits and only one patient with mean plasma GH greater than 100 ng/ml. The very wide range of concentration of GH in pituitary tumour tissue in acromegaly (Young, Bahn, and Randall, 1965;Lloyd et al, 1969) comprises part of the evidence put forward by Young et al (1965) that qualitatively different types of tumour may cause this disease. A given tumour may be heterogeneous in cell type and function but the existence of strongly eosinophilic tumours rich in GH and chromophobe tumours with very low GH concentrations, both causing acromegaly, is reasonably well established.…”

“…Blood glucose was measured in a Technicon AutoAnalyzer by the ferricyanide method of Hoffman (1937) and plasma cortisol by the method of Mattingly (1962 (0) Tissue obtained from patients who underwent biring pregnancy hypophysectomy was stored at -27°C under glycerol until extracted. Portions of the tissue were 777 BI/F homogenized in Tris-EDTA-boric acid buffer at pH 8-9 and GH concentrations were measured in the supematants removed after centrifugation (Lloyd, Donald, Catt, and Burger, 1969).…”