Effect of Insulin on Growth in Force-Fed Hypophysectomized Rats

Wagner, Edgar; Scow, Robert O.

doi:10.1210/endo-61-4-419

Cited by 41 publications

(8 citation statements)

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“…Although much of the weight gain could be attributed to fat, there was also an increase in nitrogen retention. Hyperalimentation of hypophysec tomized rats produced similar results (295); in pair-fed rats, addition of exogenous insulin did not further increase weight gain or nitrogen retention (295).…”

Section: Insulinmentioning

confidence: 82%

The Regulation of Growth by Endocrines

Daughaday¹,

Herington²,

Phillips³

1975

Annu. Rev. Physiol.

107

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Normal growth is the product of a complex interaction among nutrition, .circulating hormones, and changing tissue responsiveness. Although malnutrition is probably the world's most common cause of poor growth, the greatest advances in our understanding of the growth process have come from studies of the function of endocrine factors in normal and disordered growth. Limitations of space have led us to give greatest attention to growth hormone and somatomedin because of the many recent developments in these areas. We have emphasized clinical research in many areas to take advantage of the increases in knowledge that have come from the application of modern immunoassay techniques to growth problems in man. SOMATOMAMMOTROPINSThe importance of the pituitary growth hormone (GH) in the regulation of growth in most vertebrate species is generally accepted. Earlier studies have been extensively reviewed and will not be discussed here (34, SO, 60, Ill, 132, 153,215,222,274,297). ChemistryMajor advances have recently been made in the elucidation of the primary structure of many of the mammalian growth hormones and of the other somatotropic or lactogenic polypeptide hormones. Excellent reviews of these studies have been pre sented (182,184,195,303).Annu. Rev. Physiol. 1975.37:211-244. Downloaded from www.annualreviews.org Access provided by University of California -San Francisco UCSF on 02/08/15. For personal use only.Quick links to online content Further ANNUAL REVIEWS

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Section: Insulinmentioning

confidence: 82%

The Regulation of Growth by Endocrines

Daughaday¹,

Herington²,

Phillips³

1975

Annu. Rev. Physiol.

107

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“…It was quickly recognized that administration of insulin in rodents leads to expansion of total fat mass [47]. It was determined that this model of obesity resulted mainly from increased consumption of calories [48, 49]. However, enlargement of fat pads directly at the site of injection seemed to imply the possibility of a direct effect of insulin on lipid accumulation [50].…”

Section: How Does Hi Cause Obesity?mentioning

confidence: 99%

Hyperinsulinemia: a Cause of Obesity?

2017

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Purpose of ReviewThis perspective is motivated by the need to question dogma that does not work: that the problem is insulin resistance (IR). We highlight the need to investigate potential environmental obesogens and toxins.Recent FindingsThe prequel to severe metabolic disease includes three interacting components that are abnormal: (a) IR, (b) elevated lipids and (c) elevated basal insulin (HI). HI is more common than IR and is a significant independent predictor of diabetes.SummaryWe hypothesize that (1) the initiating defect is HI that increases nutrient consumption and hyperlipidemia (HL); (2) the cause of HI may include food additives, environmental obesogens or toxins that have entered our food supply since 1980; and (3) HI is sustained by HL derived from increased adipose mass and leads to IR. We suggest that HI and HL are early indicators of metabolic dysfunction and treating and reversing these abnormalities may prevent the development of more serious metabolic disease.

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“…WAGNER and Scow [35] reported that the small increment in nitrogen retention occurring when hypophysectomized rats were forced fed [30], was similar to that produced by the injection of insulin [29]. They speculated that insulin stimulated an increased food intake in the hypophysectomized rat.…”

Section: Introductionmentioning

confidence: 95%

The Action of Insulin, Growth Hormone, and Epinephrine on Cell Growth in Liver, Muscle, and Brain of the Hypophysectomized Rat[39]

Cheek

Graystone

1969

Pediatr Res

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ExtractThis study explores changes in deoxyribonucleic acid (DNA), ribonucleic acid (RNA), protein, and water content of muscle, liver, and cerebrum in hypophysectomized rats and the effects of injecting growth hormone, insulin, or growth hormone with epinephrine conjointly over a n eleven-day period.Male hypophysectomized rats, 26 to 49 days of age, fed an ad libitunz diet were studied. At 38 days of age they were injected with insulin, 0.4 to 1.8 units per day, with bovine growth hormone (250 pglday) or with the same amount of growth hormone and epinephrine, 5 to 20 pglday, concomitantly, or were untreated until the 49th day of age. Control rats of the same age were either pair-fed to untreated hypophysectomized rats or given an ad libitunz diet.Untreated hypophysectomized rats showed poor body weight gain per unit food intake and reduced skeletal growth. The nucleic acid and protein content of liver, muscle, and cerebrum was reduced when compared with controls of the same age. T h e ratio of protein: DNA (cell size) was increased for body size but reduced for age. -Administration of insulin caused hypertrophy of liver cells and increased the protein content of liver, but did not affect muscle and cerebrum. DNA content of liver or cerebrum did not increase, and the gain in DNA content of muscle was not remarkable. There was a definite increase in RNA content of muscle, liver, and cerebrum and in the ratios of RNA:DNA and protein: DNA of liver.Injections of growth hormone caused an increase in DNA (cell number), RNA, and protein content in liver, muscle, and cerebrum. There was a reduction in the ratio of cytoplasm to nucleus. The protein increment was nullified by the injection of epinephrine in conjunction with growth hormone. DNA content of muscle and liver was increased, but not to the level produced by growth hormone alone. The increase in RNA content of liver, muscle, and cerebrum was again significant; the ratio of RNA: DNA increased only in liver. Caloric intake of untreated hypophysectomized rats and those treated with growth hormone or insulin was comparable. Rats injected with epinephrine showed a significant increase in caloric intake.T h e results indicate that insulin is involved with growth in cell size, while growth hormone is active with respect to the increase in cell number. Both hormones are required for optimal growth. SpeculationThe present study indicates that both growth hormone and insulin are required for optimum cell growth. Epinephrine administration retards the increase in cell number that normally occurs in hypophysectomized rats receiving growth hormone. This suggests that overactivity of the sympathetic pathways may retard growth and produce effects that simulate hypopituitarism.

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Effect of Insulin on Growth in Force-Fed Hypophysectomized Rats

Cited by 41 publications

References 1 publication

The Regulation of Growth by Endocrines

The Regulation of Growth by Endocrines

Hyperinsulinemia: a Cause of Obesity?

The Action of Insulin, Growth Hormone, and Epinephrine on Cell Growth in Liver, Muscle, and Brain of the Hypophysectomized Rat[39]

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