Abstract
Growth stimulation in hypophysectomized (hypox) rats implanted with plerocercoids (spargana) of Spirometra mansonoides was first observed by Mueller (1). This initial observation has been amply verified and a number of alterations in the metabolism of the host animal have been noted (2–6). The serum collected from hypox rats with implanted pleroceroids also contains the active growth factor and some of the responses produced in the hypox rat by the administration of active serum, plerocercoids and bovine growth hormone (BGH) are described in the present report.
Methods. Male hypox and intact control rats of the Sprague Dawley strain weighing approximately 80 g were obtained from the Hormone Assay Laboratories in Chicago. All animals were housed in a constant temperature room with controlled lighting (12 hr photoperiod) and were fed a purified sucrose-casein diet (6). Plerocercoids of the tapeworm S. mansonoides were obtained from the fresh carcasses of mice that were maintained for this purpose. Scolexes clipped from the plerocercoids were prepared for sc injection into host animals by washing them in sterile physiological saline and suspending them in fresh saline containing 10,000 units of penicillin G and 12 mg of streptomycin/ml.
The concentrations of various serum constituents in host animals were determined on fresh blood obtained by cardiac puncture. The specimens were analyzed immediately, using the standardized techniques available in the clinical laboratories of the University Hospital. 2 Serum taken from hypox rats implanted with scolexes was pooled and stored at —5° for later use as a source of the plerocercoid growth factor (PGF) and is designated as WHRS (wormy hypox rat serum), as described by Garland, Ruegamer and Daughaday (4).
Liver glycogen levels were determined by the procedure of Pfleiderer (7) and glucose concentrations were measured by the method of Bergmeyer and Bernt (8).
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