Effects of relaxin on the microvasculature of mouse mammary gland

The effects of RLX on the microvasculature of the mouse mammary gland are reported. RLX (pure porcine standard NIH-RXN-P1) at a dose of 3 GPU was administered subcutaneously to virgin adult mice ovariectomized 12 days before. The mammary glands were removed 18-20 h after RLX injection and their examination by light microscopy did not reveal any substantial growth-response to the hormone. Histology and morphometry indicated striking dilation of microvessels, especially capillaries, and electron microscopy revealed an increase in the micropinocytotic vesicles, thus suggesting enhanced transendothelial transport of substances. Such phenomena, which were independent of a release of granules by mast cells, may represent an important component of the mammotrophic action of RLX.     

Effects of exogenous growth hormone on insulin action and glucose metabolism in the dwarf 'little' mouse

The in vivo actions of growth hormone (GH) on insulin activity and glucose homeostasis were examined in the GH-deficient Little mouse. The insulin-like action of GH was revealed during glucose tolerance tests on the animals after acute treatment with the hormone and the insulin-antagonistic action was demonstrated in both glucose tolerance tests and insulin tolerance tests on the mice after chronic GH infusion. The primary mechanism of the GH actions is to influence the responses of the target tissues to circulating insulin in vivo. The pancreatic function seems to be of little importance in the alteration of glucose metabolism after acute exposure to GH as no significant change of the levels of plasma insulin was detected. It is concluded that the GH-deficient Little mouse is an ideal laboratory model for the elucidation of the molecular mechanism of the interaction between insulin and GH in the regulation of carbohydrate metabolism.     

The structure of the human symphysis pubis with special consideration of parturition and its sequelae

Review of the structure of the symphysis pubis, based on my extensive study of the pelvic joints ('31) shows changes from age, function, pregnancy hormones and stress of parturition. Primary physiologic shearing clefts and secondary traumatic clefts in cartilage are more frequent in females. Inter-digitations in the young osteocartilaginous border secure the vulnerable growth cartilage against increasing shearing forces. The retropubic eminence, ligamentous or cartilaginous, forms earlier in females, later, due to bony lipping in males, secondary to extrusion of disc cartilage. Ovarian and placental hormones in pregnancy cause remodeling and resorption of the posterior margin of the pubic facette and adjacent cortex, making a (variably) deep bony groove for greatly hypertrophied transverse ligaments. Delivery of a mature infant produces traumatic changes leading to extrusion of torn fibrocartilage in any direction, progressively loosening the symphysis, producing cartilage nodules, cysts and reactive bone formation. Older age degenerative arthritis is more frequent in parous females.     

Histochemical study on glycosaminoglycans in the developing mouse vitreous

Summary The distribution of polyanionic glycosaminoglycans (GAGs) in the developing mouse vitreous was studied histologically by P.A.S. reaction, metachromatic staining by toluidin blue at various pH's alcian blue at pH 0.5 and alcian blue C.E.C. stainings, modified Hale's method with colloidal iron, and enzymatically with bovine testicular hyaluronidase.A subdivision of the vitreous developmental period into four phases and an early distinction between, the posterior and equatorial vitreous portions are suggested on basis of the results.The early vitreous, during the first developmental phase, exhibits a high content in GAGs.This property gradually vanishes in the posterior part during the second phase of development, while acid GAGs including possibly hyaluronate are present in the equatorial zone. During this second phase, the lens capsule present a strong P.A.S.-reactivity, especially positive in it's posteriors part.During the third phase, sulphated GAGs reappear in the posterior vitreous while non-sulphated material remains present in the equatorial zone.During the first two postnatal weeks (fourth developmental phase), acid GAG's disappear in the equatorial part of the vitreous but the maturing zonular fibres display the properties of sulphated GAGs. It is suggested that the histochemical maturation of the secondary vitreous starts around the 16th or 17th fetal day, i.e. much earlier than its morphological differentiation.     

Histochemical study on glycosaminoglycans in the developing mouse vitreous

The distribution of polyanionic glycosaminoglycans (GAGs) in the developing mouse vitreous was studied histologically by P.A.S. reaction, metachromatic staining by toluidin blue at various pH's, alcian blue at pH 0.5 and alcian blue at various pH's, alcian blue at pH 0.5 and alcian blue C.E.C. stainings, modified Hale's method with colloidal iron, and enzymatically with bovine testicular hyaluronidase. A subdivision of the vitreous developmental period into four phases and an early distinction between, the posterior and equatorial vitreous portions are suggested on basis of the results. The early vitreous, during the first developmental phase, exhibits a high content in GAGs. This property gradually vanishes in the posterior part during the second phase of development, while acid GAGs including possibly hyaluronate are present in the equatorial zone. During this second phase, the lens capsule present a strong P.A.S.-reactivity, especially positive in it's posterior part. During the third phase, sulphated GAGs reappear in the posterior vitreous while non-sulphated material remains present in the equatorial zone. During the first two postnatal weeks (fourth developmental phase), acid GAG's disappear in the equatorial part of the vitreous but the maturing zonular fibres display the properties of sulphated GAGs. It is suggested that the histochemical maturation of the secondary vitreous starts around the 16th or 17th fetal day, i.e. much earlier than its morphological differentiation.     

Structure of a porcine relaxin inactive on the mouse pubic ligament

In addition to B31 (CM-a) and B28 (CM-B) relaxins, acid-acetone extracts of ovaries of pregnant sows contain a third major relaxin species (relaxin C). The major components of relaxin C possess about half the activity of CM-a or CM-B in the guinea pig palpation assay, but are completely inactive in the mouse pubic ligament assay. Its uterotrophic and protein anabolic effects in ovariectomized, estrogen-primed mice, however, are comparable to those of CM-B. Sequence analysis indicates that the two major components of relaxin C, like the other porcine relaxins, consist of two polypeptide chains linked by disulfide bonds. The shorter (A) chains are identical to the A chains of the other porcine relaxins, except for the absence of the N-terminal arginine residue. The B chains display microheterogeneity; the B sequences of the two predominant species are the same as those of the other porcine relaxins through B25, but terminate at valine residue B25 or serine residue B26, respectively.     

Responsiveness of mouse parametrial fat to relaxin

The effects of relaxin on the hypertrophy of the parametrial fat cells in ovariectomized virgin mice have been studied histologically and morphometrically. This hormone has been previously demonstrated by us to induce hypertrophy also in the adipose cells of the mouse mammary gland. This effect produced by relaxin on mammary adipocytes was greater than that due to estrogen alone and independent of pretreatment with estrogen. When insulin was given after estrogen in place of relaxin the effect was nearly the same as that following relaxin alone. On the contrary, in parametrial adipocytes under the same hormonal conditions, we found an increase in the mean diameter of 28% following estrogen alone, 57% following relaxin alone, 80% when relaxin was given after pretreatment with estrogen, and 60% when insulin was given after pretreatment with estrogen at the same dose as relaxin. These results clearly reveal that relaxin is a very active hormone in promoting lipid deposition in the parametrial adipose cells, and that such an effect attains a maximum following a pretreatment with estrogen. Moreover, these findings indicate that the parametrial fat cells can be included in the list of the targets of relaxin.     

Effects of calcitonin and parathyroid hormone on the metabolism of chondrocytes in culture

Rabbit articular chondrocytes in suspension culture synthesize Type II colagen [3α₁(II)] in the absence of extracellular Ca²⁺ and Type Icollagen [2α₁?(I)·α₂] in the complete medium. As a result of pre-treatment in monolayer culture with calcitonin or parathyroid hormone in the complete medium, an influx of Ca²⁺ into the cells occurs. These cells produce mainly Type I collagen when transferred to suspension cultures in the medium devoid of CaCl₂. If added directly to the suspension culture medium containing no CaCl₂, calcitonin stimulates an active efflux of Ca²⁺ from the cells into the medium and leads the cells to synthesize Type I collagen. Under similar conditions, parathyroid hormone does not change the collagen-phenotype.     

Effects on drug metabolism of carbaryl and 1-naphthol in the mouse

The effects of carbyl and 1-naphthol on hepatic microsomal drug-metabolizing enzyme systems were investigated. The agents were fed at a level of 25 mmol/kg of feed to groups of young male Swiss-Webster mice for 14-day periods. Body weight was depressed by carbaryl, but not by 1-naphthol. The rates of $\text{in vitro}$ metabolism of aniline and benzphetamine were greater than control rates in livers of mice fed carbaryl, but the rate of $\text{in vivo}$ hydrolysis of the carbamate insecticide Zectran was decreased by carbaryl feeding. Administration of 1-naphthol did not change the rates of $\text{in vitro}$ metabolism of either aniline or benzphetamine. Hepatic microsomal concentrations of cytochromes P-450 and b₅ were increased by carbaryl, but feeding of 1-naphthol did not affect levels of either cytochrome. Radiolabeled pentobarbital disappeared from the blood of carbaryl-fed mice more rapidly than from the blood of control animals, and carbaryl-fed mice slept a shorter period of time than controls following pentobarbital administration. The LD50 of an acute oral dose of carbaryl was increased two-fold by feeding carbaryl for 14 days. It was concluded that carbaryl is a weak inducer of hepatic microsomal drug-metabolizing activity, and that the effects observed are not likely due to 1-naphthol.     

Effect of lectins on the metabolism of sulfated glycosaminoglycans in cultured fibroblasts

A short exposure of human skin fibroblasts to Concanavallin A and wheat germ agglutinin led to an intra- and extracellular accumulation of sulfated glycosaminoglycans. The intracellular accumulation was caused by an impaired degradation of sulfated glycosaminoglycans. The increase of extracellular and cell surface associated ³⁵S-labeled proteoglycans could be ascribed to a lectin-mediated inhibition of endocytosis of these polysaccharides. Results obtained with mono- and divalent Concanavalin A derivatives were in aggreement with the view that lectins inhibit endocytosis of sulfated proteoglycans by binding to the cell surface receptors specific for these polysaccharides. Proteoglycans secreted by fibroblasts formed predipitable complexes with Concanavalin A. Complex formation reduced markedly the uptake of the proteoglycan. All effects on glycosaminoglycan metabolism mediated by Concanavalin A and wheat germ agglutin could be prevented by methyl α-D-mannoside and N-acetylglucosamine, respectively.     

Effects of growth hormone on glucose and acetate metabolism in sheep

The effect of intravenous infusion of growth hormone (GH) on glucose metabolism in sheep was determined. To maintain low levels of insulin somatostatin was infused with and without GH. The infusion of GH for 6 hr was without effect on glucose metabolism.