Henry C. Damm

Effect of pregnenolone, progesterone, and derived metabolites on mammary gland growth in rats.

Summary Compounds in a steroidogenetic pathway (pregnenolone → progesterone (P) → 17α-hydroxyprogesterone → androstenedione → testosterone propionate) were tested to determine their mammogenic effectiveness (as determined by desoxyribosenucleic (DNA) measurement) in ovariectomized rat when injected with estradiol benzoate (EB). Results indicated that EB plus P produced greatest total mammary gland DNA. EB plus pregnenolone, 17α-hydroxyprogesterone, androstenedione or testosterone propionate produced 29.0%, 26.5%, 35.8%, and 33.0% of DNA produced by EB plus P over that produced by injection of EB alone.

Desoxyribosenucleic acid as index of mammary gland growth of mice.

Summary 1. Total DNA of the mouse mammary gland is an index of mammary gland development while concentration (μg DNA/mg dry, fat-free tissue) seems to be an index of growth rate. 2. Feeding 1.23 mg diethylstilbestrol/kg mouse food caused most rapid mouse mammary duct development between the second and third weeks. 3. Rate of mammary gland growth is not constant. At the end of a 10-day period, mice injected with lower doses of lobule-alveolar developing substances seemed to be developing at a faster rate, whereas those receiving a higher dose had a greater amount of absolute growth, although the rate of development had passed the peak.

Effects of Hormone Dose and Length of Injection on Mouse Mammary Gland Growth.

Summary The possible use of growth curves in assay procedures for mammary-gland growth promoting substances was investigated. Male mice were fed diethylstilbestrol for 4 weeks to insure duct growth. In addition, one group was injected subcutaneously with 0.75 μg estradiol benzoate (E.B.)/day along with various levels of progesterone (P) for 5- or 10-day periods. Another group similarly received 0.50 μg E.B./day plus various amounts of P for a 10-day period. Desoxyribosenucleic acid determined by a newer, shortened procedure was used as a growth index. Results indicated that best slope with greatest precision was obtained when 0.75 μg E.B./day with various amounts of progesterone was injected for 10-day period.

Effect of anterior pituitary preparations on rat mammary gland growth.

Summary Using desoxyribosenucleic acid (DNA) as an index of mammary gland growth, crude and purified anterior pituitary extracts were tested for mammary gland growth promoting (mammogenic) effectiveness. Acetone dried AP powder and an initial extract of AP were shown to be effective in stimulating production of mammary gland DNA. Initial residue, Mammogen “A” and “C”, shown previously to produce mammary gland growth in mice, were found to be ineffective in rats. Fractions rich in lactogen and growth hormone were found to be minimally effective in stimulating mammary gland lobule-alveolar growth.

Uptake of P32 by Pigeon Crop-Sac as Index of Lactogenic Hormone.

Summary Studies were conducted on ability of purified and crude lactogenic preparations to stimulate incorporation of P31 and P32 in crop-sac of pigeon. Lactogenic hormone injected intradermally over one side of crop-sac stimulated significant P31 and P32 incorporation as compared to control sides. Diametric responses were correlated with % P32 uptake after injection of crude pituitary homogenates with a resultant correlation coefficient of .79, indicating that P32 incorporation is primarily a function of lactogenic activity of homogenate injected.

Effects of anterior pituitary preparations on mammary gland growth in mouse.

Summary Mammogenic potencies of a number of crude and purified anterior pituitary fractions were determined by estimation of mammary gland desoxyribosenucleic acid (DNA) in treated ovariectomized mice. Crude bovine AP, initial residue (IR) obtained by depleting AP of known hormones, a newly developed mammogen extracted from IR (mammogen “C”) and lactogenic preparation produced lobule-alveolar development. Extracted mammogen “C” was white, crystalline, apparently salt-free and water soluble. Crude and purified FSH and growth hormone exhibited little or no mammogenic effects when injected with a synergizing dose of estradiol benzoate in ovariectomized mouse.

Long-Term Effect of Estrogen and Progesterone on Mammary Gland Growth in 3-Methylcholanthrene Treated and Non-treated Ovariectomized Rats.

Summary Administration of 1 μg estradiol benzoate plus 3 mg progesterone into ovariectomized rats for 20 days produced mammary gland DNA levels comparable to those observed in rats on 19th day of pregnancy, while continued injection for periods of 30, 40 and 50 days did not significantly increase observed growth. However, no involutionary changes were noted with long-term injection, indicating a maintainence of the lobule-alveolar system. Administration of 10 mg 3-methylcholanthrene twice weekly for 7 weeks reduced mammary gland growth by approximately 25% in ovariectomized rats given 1 μg estradiol benzoate plus 3 mg progesterone or twice this amount. These hormones prevented development of observable mammary tumors.

Extraction and concentration of mammogenic fractions from anterior pituitary gland.

Summary It has been shown that appreciable quantities of mammogenic factor are left in initial residue of anterior pituitary gland after extraction of the known hormones by usual technics. This factor was extractable by either a monosodium-disodium phosphate buffer solution or a saline solution. The active factor precipitated from the phosphate buffer system along with phosphate salts after addition of ethanol and butanol and adjusting the pH to 12.5. Phosphate salts were subsequently removed by dialysis, during which mammogenic hormone precipitated out of solution. Active factor was precipitated from saline solution by saturation of solution with NaCl and chilling. Resulting light grey, amorphous powder obtained by phosphate extraction was 223 times more potent in promoting mammary gland growth than progesterone, and contained negligible, if any, lactogenic activity. A highly purified lactogenic preparation assayed for mammogenic activity at the same time was only 1.59 times as potent as progesterone. On this basis the lactogen need contain no more than 0.71% of mammogen to produce the biological response observed.

Evidence for existence of mammogenic hormone

Summary Improved objective technics for assay of lactogenic and mammogenic hormones have been developed. The amount of lactogen and mammogen has been estimated in several different pituitary preparations by these assay methods. Wide differences in lactogen/mammogen ratios between preparations were demonstrated. These observations are taken to indicate that the pituitary hormone stimulating mammary gland growth (mammogen) is different from the hormone stimulating milk secretion (lactogen).