Pituitary Growth Hormone and the Glucose Utilization of Rat Diaphragm

Abstract

Growth hormone has been reported to cause either a depression or a stimulation of the glucose uptake of isolated rat diaphragm. The present paper describes further work on the two effects.1. Anaerobic conditions during the preparation of the diaphragm for incubation affect the glucose uptake and alter the response of the muscle to growth hormone. By controlling the oxygen tension in the diaphragm immediately after excision, variation of the glucose uptake and the effect of the hormone is reduced.2. Solutions of growth hormone were found to be extremely labile, but, by rigidly standardizing the method of preparing solutions, consistent results were obtained.3. The relationship between the concentration of growth hormone and its effect on the glucose uptake of isolated diaphragm was investigated separately for muscle saturated with oxygen and with nitrogen. With oxygenated muscle at high concentrations the hormone stimulates, and at low concentrations depresses, the rate of glucose uptake.4. The mode of action of growth hormone in vitro and in vivo is discussed.

The interaction of growth hormone and insulin in the perfused rat heart

“…This is important since the nature of the dose-response curve of B 168 would be much easier to explain if factor (1) were considered as a mixture of two agents. Ottaway & Bulbrook (1955) have suggested that a single type of cell could show a biphasic response to a single hormone, but demonstration of such an effect calls for a demonstrably single hormone. At present it is not possible to determine whether the growth hormone itself has depressant, stimulant, biphasic or zero effect on the glucose uptake of the heart.…”

Proceedings of the Biochemical Society

“…The presence of insulin-like activity in growthhormone preparations has been reported (Park, Brown, Comblath, Daughaday & Krahl, 1952;Ottaway & Bulbrook, 1955), and partial separation of the activity from growth-hormone preparations, using ultrafiltration, was reported by Ottaway & Paul (1957). Separation and complete purification of a peptide with insulin-like properties has now been accomplished by electrophoretic techniques.…”

Interactions of Insulin, Pituitary Factors, and Adrenal Hormones in Isolated Tissues

“…Since Ottaway (1953) had suggested that the insulin-like effects of growth hormone might be due to displacement of insulin from inactive tissue loci, Manchester and Young repeated the test with growth hormone in the presence of quantities of insulin antiserum which blocked the effects of small quantities of insulin; the growth hormone stimulation was unimpaired, implying that it was not due to contamination w 7 ith, or displacement of, insulin. found beef growth hormone (50 ^g./ml. )…”

“…This raises the possibility that the humoral inhibitor is a fragment of growth hor mone carried with the ß-lipoprotein of rat serum, and possibly with other serum proteins of other species ( Vallance-Owen et al, 1958 ). Other aspects of the interrelationship between the action of insulin, growth hor mone, and/or cortical steroids upon isolated rat diaphragms have been dealt with by Verzar and Wenner (1948), Bartlett et al (1949), Ottaway (1953Ottaway and Bulbrook, 1955), and in the reviews by Ketterer et al (1957), and Manchester and Young (1961). Stadie (1954) found that the anti-insulin effect of injected pituitary factors upon glycogen synthesis was not due to a reduction of the quantity of in sulin which became attached to the diaphragm, but to interference with the effect of that which did become attached.…”