Multiple forms of growth hormone: detection in medium from cultured pituitary adenoma explants

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Abstract
Three pituitary adenomas obtained from patients with acromegaly were maintained in organ explant culture for a period of 12 days in a defined culture medium. Lyophilized culture medium from each was then examined by electrophoresis to determine which forms of growth hormone [GH] were secreted by the explants. All 3 explants secreted principally the major form of GH. One adenoma secreted unusually large amounts of 2 slowly migrating forms which were in low concentration in the GH-containing granules of normal pituitaries. The adenoma produced a much lower amount of a 20,000-dalton variant than was seen in normal pituitary glands. The other 2 adenomas did not secrete the relatively large amounts of the slowly migrating forms although the quantity of the 20,000-dalton form was less than the amount seen in the normal pituitary. There was no evidence of proteolytic alteration of the GH during the culturing process. In companion experiments with rat pituitary glands the GH did not undergo proteolytic degradation in the gland left in situ for 96 h at 5.degree. C.