Specificity and properties of anti-adenohypophysis serum. I. Mode of preparation, titration and effects of neonatal injection into rats.

Antisera to rat adenohypophysis were prepared in sheep by using viable adenohypophysial cells. A method for the in vitro evaluation of the anti-adenohypophysis activity was described. The effect of the antiserum on growth hormone-producing cells has been proved by the long lasting growth inhibition after a single injection into newborn rats. Specificity for adenohypophysial cells was shown by absorption procedures in vitro. Histological examination of other endocrine glands (thyroid, adrenals, gonads, pancreatic islets) did not reveal any evident pathological modifications after injections of the antiserum. Electron micrographs of the adenohypophysis of rats injected at birth showed pronounced alterations of all growth hormone-producing cells 30 days later. The use of this anti-adenohypophysial serum is suggested when a durable specific blockade of the STH-producing cells is required without untoward toxic side effects as e.g. in STH-dependent tumour growth.