R. von Berswordt-Wallrabe

Effect of Lactogenic Hormone, Growth Hormone and Thyroxine in the Lactating Albino Rat.

Summary Effects of lactogenic hormone (LGH) alone and in combination with growth hormone (GH) and L-thyroxine (T4) upon lactation in the rat have been studied. All rats were nursed on day 14 of lactation with aid of 1 USP unit of oxytocin (OXT) under standardized conditions. One mg LGH alone did not show galactopoietic effects when injected daily from day 7–14. Under combined action of 1 mg LGH and 1 mg GH/day from 7–14, litter weight gain and amount of milk on day 14 have been significantly increased. Addition of 3.0 μg T4/100 g body weight/day from day 7–14 to LGH plus GH resulted in a more highly significant increase in milk yield in comparison to oxytocin alone than did treatment with LGH plus GH. The increase in mean milk yield of 84% over untreated controls by 4 hormones is the highest so far attained in laboratory.

Influence of Graded Levels of Progesterone in Ovariectomized Rats upon Placentomata Formation Measured by Total DNA.

Summary Sprague-Dawley-Rolfsmeyer rats were ovariectomized in estrus, then administered progesterone (P) at rate of 1.5 mg/day for 5 days (pretrauma period). Endometrium of one uterine horn of each animal was scratched throughout its entire length by sharp needle. During post-trauma period, days 6 to 9, P at levels of 1, 2, 3, and 6 mg was injected daily. On day 10 each uterus was separated into control and traumatized horn, weighed and processed for DNA determination. The traumatized horns showed a graded increase in wet weight, DFFT, and DNA/100 g B.W. over control horns when 1, 2, and 3 mg/day of P were administered during post-trauma period. Six mg/day did not increase reaction further. Considerable variation in reaction occurred in each group requiring a considerable number of animals for use as assay method.

Successful Replacement Therapy in Lactating Thyro-parathyroidectomized. Rats.

Summary Thyroparathyroidectomy was performed in 44 lactating rats on day 7 postpartum. Successful replacement therapy was started immediately after surgery with optimal level of T4 (3 μ 100 g day), 2 × 40 USP units PTH day (corresponding to 29-30 USP units 100 g day) and 1 USP unit OXT for complete milk removal on days 14-18. Litter weight and milk yield on day 14 reached levels of normal animals given optimal amounts of T4 (3 μg 100 g day) and 1 USP unit OXT for milk yield test. Discontinuation of PTH on day 13 resulted, within 6-18 hours, in 10 fatal attacks of tetany in a group of 12. Withdrawal of PTH on day 14 coincided with 10 hour isolation period for milk yield test. A group of 15 such animals survived considerably longer than previous group, due, it is believed, to gradual inhibition of lactation and reduction in blood Ca removed during separation period. In 11 rats which succumbed to tetany later, milk yield was significantly higher on day 15 as compared to day 14, 29 hours after last PTH injection. Nine rats which lactated normally without exhibiting signs of tetany during 4 day period after withdrawal of PTH, were considered to have (accessory) parathyroid tissue. It is tentatively proposed to consider 29-30 USP units of PTH/100 g/day as estimate of parathyroid secretion rate in this strain of intensively lactating rats under beneficial influence of optimal T4 level.

Dihydrotachysterol (AT 10) and Mammogenesis in Ovary-Thyro-Parathyroidectomized Rats.

Summary Daily administration of 1 μg EB plus 3 mg P to mature ovary-thyro-para-thyroidectomized rats for 19 days stimulated mammary gland growth (DNA) comparable to ovariectomized rats receiving same treatment. Replacement therapy with 10 and 20 μ AT 10/100 g/day, respectively, in combination with 1 μg EB plus 3 mg P increased total DNA significantly. No benefit was observed by increasing ovarian hormones to 2 μg EB plus 6 mg P. Combined administration of AT 10 at above mentioned levels and 1.5 μg and 3 μg T4/100 g depressed DFFT significantly resulting in reduced total DNA.

Influence of Lactogenic Hormone and Estradiol Benzoate upon Placentoma Formation in Intact Rats Measured by Total DNA.

Summary Sprague - Dawley - Rolfsmeyer rats showing full estrous smears were administered 1 mg/day of ovine lactogen containing 15 IU/mg for 5 days. On day 6, one uterine horn was traumatized and 1 μg EB and 1 and 2 mg lactogen (LGH) were administered on days 6 to 9. On day 10, horns of uteri were separated and processed for DNA. EB had no influence on placentoma formation; whereas, both levels of LGH stimulated placentoma in 1/3 of rats with graded reaction as measured by DNA. EB, .5 μg or 1 μg, with 1 mg LGH improved neither % response nor total DNA in comparison with LGH alone. While lactogenic preparation stimulated placentoma formation, reasons are advanced why it is premature to identify luteotropic action with lactogen.

Mammogenesis in ovary-thyro-parathyroidectomized rats.

Summary Daily administration of 2 μg estradiol benzoate plus 6 mg progesterone to mature ovary-thyro-parathyroidectomized rats for 19 days resulted in mammary gland growth (DNA) comparable to ovariectomized rats receiving same treatment. Replacement therapy with 3 μg thyroxine/100 g BW depressed total DFFT and increased DNA concentration but failed to increase total DNA equal to that of ovariectomized rats so treated. These data suggest that higher levels of ovarian hormones may offset thyro-parathyroid hormone deficiencies. With 3 μg thyroxine/100 g BW total DNA of glands did not equal those of ovariectomized group. It is suggested that lack of comparable response may be due either to lack of parathormone or slight excess of thyroxine.

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.

Erfolgreiche Substitutionstheraphien in thyreo-parathyreoidektomierten lactierenden Albinoratten

2 × 40 USP-Einheiten PTH (Parathromon4)/Tag, was etwa 29 bis 30 USP-Einheiten PTH/100 g KG (Korpergewicht) entspricht, subcutan oder 60, 80 bzw. 100 γ A.T. 10 (antitetanisches Praparat Nr. 10 oder Dihydrotachysterin5)/100g KG, per os, hielten in vollstandig thyreo-parathyreoid-ektomierten (TPEK) lactierenden Ratten eine intensive Lactation aufrecht.

Influence of Progesterone, Estradiol Benzoate, and Thyroxine in Ovariectomized Rats upon Placentomata Formation Measured by Total DNA.∗

Summary Progesterone (P) has been shown to stimulate placentomata formation in traumatized horns of rat uteri. Influence of estradiol benzoate (EB) and thyroxine (T4) as possible synergists in this reaction using DNA as an index was studied. Slight, but not significant, increases in various indices of placentomata growth were observed when EB or T4 were administered separately with P. Highly significant increases were observed, however, when 2 μg EB + 6 mg P + 3 μg T4/100 g BW were administered. The same level of these 3 hormones stimulated a significant increase in mammary gland growth, indicating similar response in 2 tissues of reproductive system.