The influence of hypophysectomy on NSILA concentrations in the dog: evidence for partially pituitary-independent regulation.
Non-suppressible insulin-like activity (NSILA) was determined in 5 dogs before and after hypophysectomy. All NSILA determinations were carried out on serum samples after acidic Sephadex G-50 chromatography by two different assay systems, i.e. a bioassay and a protein binding assay. The levels of NSILA decreased significantly after hypophysectomy and returned to near normal levels after 2 weeks. T3-, T4- and cortisol levels were drastically reduced during the entire period of the experiment. Several GH determinations after hypophysectomy revealed very low levels. Insulin-induced hypoglycaemia failed to provoke a rise of GH levels as late as 4 months after hypophysectomy. These findings indicate that: 1) The pituitary gland cannot be the site of synthesis of NSILA. 2) NSILA concentrations in the dog are maintained at a near normal level in the presence of very low growth hormone and thyroid hormone concentrations, so that these latter hormones do not appear to be the only regulatory factors concerned in NSILA synthesis.
D000818:Animals; D004285:Dogs; D005260:Female; D013006:Growth Hormone / Q000097:blood; D006854:Hydrocortisone / Q000097:blood; D007016:Hypophysectomy; D007328:Insulin / Q000097:blood*; D010902:Pituitary Gland / Q000378:metabolism; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D007328:Insulin; D014284:Triiodothyronine; D013006:Growth Hormone; D013974:Thyroxine; D006854:Hydrocortisone