Somatotropin Administration Research Articles

Changes in NSILA-S in Response to Somatotropin Administration and Hypophysectomy*

The effects on the serum levels of NSILA-S of the administration of human GH (hGH) or of hypophysectomy have been studied. hGH given im (5 mg daily for 3 days) raised the NSILA-S levels of three GH-deficient subjects into the normal range. Significant elevations of NSILA-S were also seen in three normal subjects given im GH. In the same groups of three normal and three GH-deficient subjects, 5 mg hGH administered iv induced an elevation of NSILA-S within 15-60 min. Hypophysectomy in three acromegalics and one subject with a chromophobe adenoma was followed by significant falls of serum NSILA-S. These studies provide further evidence of the dependence of NSILA-S levels on GH.

Morphofunctional Differentiation in the Liver: 2. Modification of the total regenerative response by selected reticuloendothelial active agents

The purpose of these experiments was to determine whether materials physically present in, and modifying the activity of, the reticuloendothelial (RE) cells could influence selected metabolic functions in hepatic parenchyma, and modify the overall regenerative growth in partially resected livers. Induction of tyrosine transaminase by endotoxin or cortisone, and repression, of either endogenous or hormonally induced glyconeogenesis by the toxin, progressed as well in partially hepatectomized animals as in normal mice. The uptake, binding and association of 3 H-cortisone with its receptors was largely uninfluenced by partial hepatectomy. In doses that stimulate the RE function, administration of either bacterial endotoxin or cortisone resulted in a delayed burst of 3 H-thymidine incorporation in regenerating livers. In, higher doses, cortisone lowered DNA synthesis associated with regeneration. Celite or bentonite also retarded the onset of DNA formation after partial hepatectomy. Moreover, the regenerative growth was almost completely eliminated in animals which had been rendered tolerant to bacterial endotoxin prior to surgery. Post-operative administration of bovine somatotropin, or phagocytosis of latex particles, however, did not influence the increased 3 H-thymidine incorporation associated with the regenerative growth. These results are discussed as a model to explore possible intercellular co-operation regulating a variety of cellular responses.

Action of metabolic hormones on the fine structure of liver cells. II. Effects of hypophysectomy and chronic administration of somatotropin.

AbstractElectron microscopic studies of hepatocytes from sham‐operated, hypophysectomized, and hypophysectomized rats treated with somatotropin were undertaken in order to obtain morphological information on the mechanism of hormone action at the cellular level. Fed and fasted animals from each of the above groups were studied. Hepatocytes from fed rats of the three groups showed similar characteristics: periportal cells contained large dense masses of glycogen throughout the cytosome with relatively little smooth endoplasmic reticulum; mid‐lobular cells displayed small dense masses of glycogen with few associated elements of smooth endoplasmic reticulum; centrilobular hepatocytes showed dispersed glycogen and abundant smooth endoplasmic reticulum. Hepatocytes from hypophysectomized rats fasted fifteen hours showed significant alterations in structure when compared with liver cells from sham‐operated animals. Differences noted were: decrease in mid‐lobular cell size and amount of smooth endoplasmic reticulum; decrease in glycogen, number of ribosomes and polysomes per hepatocyte; disorganization of the rough endoplasmic reticulum; and swelling of mitochondria and increase in number per cytoplsmic volume. Periportal hepatocytes from fasted hypophysectomized rats treated with somatotropin for ten days contain numerous small masses of glycogen with elements of smooth endoplasmic reticulum at the periphery of the glycogen masses. Mid‐lobular and centrilobular hepatocytes contain masses of dispersed glycogen with an abundance of smooth endoplasmic reticulum associated with the glycogen particles.

Growth-promoting effects of ovine somatotropin and prolactin in tadpoles of Rana temporaria

Intraperitoneal administration of either ovine somatotropin or ovine prolactin increases body-weight gain and body-length growth in tadpoles of Rana temporaria. Contrary to results obtained with other investigated anuran species, somatotropin is the more effective of the two hormones in R. temporaria.

GLASSER SR: Interrelationship of actions of glucagon and somatotropin on protein metabolism in the fasted hypophysectomized rat.

The metabolic effects of daily injections of glucagon during a 3-day fast were investigated in the case of hypophysectomized female rats. In contrast with the fasted intact or adrenalectomized rat, administration of glucagon to the hypophysectomized animal did not cause an increased excretion of urinary nitrogen, did not result in a greater loss in body weight or in mass of liver and muscle, and did not depress the level of blood a-amino nitrogen. Administration of bovine somatotropin (growth hormone) to the fasted hypophysectomized rat resulted in decreased excretion of nitrogen, decreased loss of body weight, decreased loss of liver and kidney weight, and a small but significant fall in blood a-amino nitrogen. Administration of glucagon to the somatotropin-treated hypophysectomized rats caused a partial or complete reversal of the effects of somatotropin on body weight, organ weight and urinary nitrogen excretion. On the other hand, simultaneous injections of both hormones further depressed the level of blood a-amino nitrogen compared with that of the control animals. These results suggest that the protein catabolic action of glucagon in the fasted rat is dependent at least in part upon the presence of the pituitary, specifically growth hormone.