Gebäude 21, 1. OG
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Radioimmunoassays were established for measurement of dog and rat growth hormone in dog-sera or rat-pituitary cellculture media. CGH and RGH were labelled with 125 I-sodiumiodide using the chloramin-T-method. Free and bound antigen were separated in the double-antibody-method and the assay conditions optimised. Sera of normal dogs (17) revealed a CGH-level of 4,06 +/0,78 ng/ml (Mean +/- SEM). In akromegalic 93 and 33 ng/ml CGH, and in dwarf-dogs 0,78 and 2,56 ng/ml CGH were determined. Xylazine or clonidine treatment showed elevated CGH levels in sera. The data found are in agreement with those reported. RGH was measured in cell cultures of rat anterior pituitary cells in a RGH-Radioimmunoassay.Suspensions of 194 anterior pituitary glands of Wistar and Sprague Dawley-rats were prepared in different enzymatic cellseparation-methods. Testing for cellmorphology, -yield and -vitality of 119 samples in 11 trials yielded in a continuous Trypsinization in 90 min at 37°C 833000 cells/animal with 60,3 % alive. Fractionated Trypsinization proved with 1,09 million cells/animal and 97,3 % vitality superior esults and no differences in morphology were observed. RGH-levels in cell-homogenates decreased with cell-concentration.Anterior pituitary cell suspensions, cultures of the GH3-line and primary cultures of rat anterior pituitary cells were incubated in static and different perifusion systems and stimulated with GRH, PGE 2, KCl and Epinephrine-HCl. In perifusion systems reproducible elevated growth hormone secretion was determined. The best results were obtained in a stable perifusion system of small volume, containing 1,6 to 4,8 million anterior pituitary cells after 5 day inkubation: Stimulation af-ter 4 h, 15 min equilibration-time with GRH resulted in a rise of RGH-secretion.