Robert J. Boucek

Hormonal Effects Upon in vitro Cholesterol Synthesis

This report concerns a comparison of the rates at which labeled acetate is converted into digitonin-precipitable substance by sponge connective tissue and the liver. The effects of the gonads and the thyroid gland on the in vitro incorporation of C14-labeled acetate as cholesterol were also explored.

Rate of Collagen Formation in Biopsy-Connective Tissue of the Rat

Summary (1) Collagen was found initially in connective tissue biopsy of male and female rats at 7 days following sponge implantation. (2) Collagen content of connective tissue biopsy increased rapidly in both sexes during the first 14 days of tissue growth. (3) After 21 days of connective tissue development in the female, collagen content remained constant up to 300 days of tissue age while in the male, collagen content continued to increase as the tissue aged. (4) The percentage of total scleroprotein which was solubilized by 0.5 M acetic acid decreased with tissue age and this decrease was greater in the 300-day-old tissue of the male rat than in comparable tissue of the female.

A reaction of water with rat-tail tendons (hydration-elongation)

Abstract 1. 1. The rate of lengthening of a dry tendon was analyzed when water, water-salt, and water-alcohol solutions were added. 2. 2. An empirical-mathematical treatment of the experimental data resulted in a certain constant ( K HE ) which could be related to the temperature (1/ T ), dielectric constant ( D ) and ionic strength (μ) of the water solutions. 3. 3. The experimental findingswere compared with recent knowledge of the inteaction of water with proteins. Also, the influence of the solvent was examined in light of the possible existence of electrostatic stabilization forces in the collagen-mucopolysaccharide interaction of tendons.

Incorporation and Conversion of Lysine-2-C14 in Rat Biopsy-Connective Tissue

Summary 1. C14-labeled lysine administered intraperitoneally into the rat is incorporated within hours into the saline-soluble and -insoluble non-collagenous protein and collagen of biopsy-connective tissue. Radioactivity is confined to lysine in all fractions of connective tissue except for a portion which is converted to hydroxylysine in the collagen. 2. Following appearance of radioactivity in all fractions of connective tissue, decay occurs rapidly in saline-insoluble non-collagenous protein and saline-soluble protein and slowly in the collagen fraction. Thirty days after injection of labeled lysine approximately 10% of maximum activity remained in the saline protein fractions while 30% remained in collagen. 3. Incorporation of labeled lysine into the non-collagenous protein of connective tissue is not influenced by tissue age while its incorporation into the collagen appears to decrease with tissue age. 4. Specific activity of labeled hydroxylysine from a 300-day old tissue of a female rat was approximately twice that of a comparably aged tissue from a male rat.

In vitro Incorporation and Hydroxylation of Lysine-2-C14 In Rat Biopsy-Connective Tissue.

Summary 1. Lysine-2-C14 becomes incorporated and hydroxylated in connective tissue incubated in Krebs-Henseleit medium for 12 hours. 2. Specific activity of collagenous and non-collagenous protein in the tissue studied in vitro was greater than that in tissue studied in vivo. 3. Hydroxylation of labeled lysine appears to occur more effectively in connective tissue of rats given labeled lysine intraperitoneally than in the connective tissue incubated with lysine-2-C14.