trypsinogen and Starvation

The effect of starvation for 3, 5, or 7 d on body weight, fat stores, pancreatic weight, and enzyme composition was studied in 300 g rats and was compared with a 3-d fast in 200 g rats. In the 300 g animals, fasting led to a gradual hypotrophy of the pancreas with a marked, continuous decrease in amylase content. Pancreatic lipase, trypsinogen, chymotrypsinogen, proelastase, and secretory trypsin inhibitor contents increased temporarily, but by d 7, they declined to about the initial values. This decline in enzyme levels coincided with the exhaustion of fat stores. The decrease in amylase content could be related to decreases in circulating insulin levels, whereas the temporary increase in lipase content may be owing to changes in plasma free fatty acid concentrations. In 200 g rats, starvation for 3 d led to exhaustion of fat stores that was accompanied by greater losses of pancreatic weight, protein, and amylase contents. In addition, the levels of trypsinogen and chymotrypsinogen decreased and lipase was unchanged. These findings indicate that during starvation, changes in pancreatic secretory enzymes are time-dependent and vary with the age, body weight, and/or adipose tissue mass of the rats.

Topics: Adipose Tissue; Amylases; Animals; Blood Glucose; Chymotrypsinogen; Enzyme Precursors; Fasting; Fatty Acids; Insulin; Lipase; Male; Organ Size; Pancreas; Pancreatic Elastase; Rats; Rats, Inbred Strains; Starvation; Time Factors; Trypsin Inhibitors; Trypsinogen

Starving of rat pups at the 5th or 10th day of life for three days led to lower body and pancreatic weights compared to age-matched controls. When compared to the weights before fasting, only the 5-day-old pups showed increases in pancreatic protein and DNA contents despite food deprivation. Pancreatic acinar responsiveness to carbachol stimulation was not affected. Accumulations of amylase and lipase in the pancreas of the rat pups were increased by fasting, with an accompanied surge in the level of serum corticosterone. In 10-day-old rat pups, injection with aminoglutethimide (AG), a drug which suppresses steroidogenesis, prevented the enzymatic increases and concomitantly suppressed the serum total corticosterone levels at 12 and 24 hr after the onset of fasting. These results strongly support the role of corticosterone in the modulation of the pancreatic adaptation to food deprivation in the suckling rat.

Topics: Aminoglutethimide; Amylases; Animals; Animals, Newborn; Body Weight; Carbachol; Cells, Cultured; Corticosterone; DNA; Lipase; Microbial Collagenase; Organ Size; Pancreas; Proteins; Rats; Rats, Inbred Strains; Starvation; Trypsinogen