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Biomedical subjects

F J Zeman

Publications and source records attributed to F J Zeman.

At least 37 records · Page 2Linked to original sources
PubMed1979

Production and metabolism of thyroid hormones in protein-deficient and food-restricted pregnant rats.

Thyroxine (T4) and triiodothyronine (T3) concentrations in the plasma and their metabolic clearance and production rates were studied in pregnant protein-deficient and food-restricted rats on the 20th day of gestation. Total T3 levels in the plasma were significantly reduced in malnourished dams, with those of food-restricted dams being consistently lower than those of protein-deficient dams. There were no changes in plasma total T4 concentrations as a result of dietary treatment. Unbound T4 and T3 in the plasma were significantly reduced in both protein-deficient and food-restricted dams. Maternal protein deficiency significantly lowered fetal T4, whereras food restriction caused an elevation. Metabolic clearance rates of T3 and T4 and production rate of T4 were unaffected by diet, while the production rate of T3 was significantly increased in protein deficient dams. Thyroxine to triiodothyronine ratios in malnourished dams were elevated suggesting depressed peripheral conversion of T4 to T3. Alternative factors which may lead to these effects are discussed.

Animals↗
PubMed1979

Hypothalamic thyrotropin-releasing hormone and maternal plasma TRH-peptidase activity in protein-deficient and food-restricted pregnant rats and their fetuses.

This study examined the effects of protein deficiency and food restriction on hypothalamic TRH in pregnant rats and their fetuses. The absolute and relative amounts of TRH in hypothalami were not significantly changed by diet in either dams or fetuses. Plasma TRH-peptidase activity in the dam was significantly reduced by protein deprivation, whereas food restriction caused a lesser reduction. Fetal hypothalamic TRH was less affected by maternal malnutrition than was fetal body size.

Animals↗
PubMed1979

Effects of protein deficiency and food restriction during gestation in rats on maternal and fetal plasma and pituitary thyrotropin levels.

The effects of protein deficiency and food restriction during pregnancy on maternal and fetal plasma and pituitary thyrotropin (TSH) levels were investigated on day 20 of gestation. The same parameters were also determined following administration of exogenous thyrotropin-releasing hormone (TRH). Maternal plasma and pituitary basal TSH concentrations were significantly elevated in protein deficiency. TRH injection to protein-deficient dams caused a marked reduction in pituitary TSH concentration, suggesting that the elevated plasma TSH seen in uninjected dams might be due to decreased metabolic clearance rather than to hypersecretion by the pituitary. Food restriction resulted in significant lowering of plasma TSH, but did not alter pituitary TSH in comparison to that of control dams. TRH administration had no effect on pituitary TSH concentration in food-restricted and control dams. Pituitaries of fetal young of protein-deprived dams were significantly smaller and contained significantly less total TSH, accompanied by a slight reduction in circulating plasma TSH. These observations are suggestive of developmental and functional retardation of the fetal pituitary. Fetal pituitary TSH was unaffected by TRH administration to control and food-restricted dams whereas, in young of protein-deprived females, total gland TSH was reduced.

Animal Nutritional Physiological Phenomena↗
PubMed1977

Effect of prenatal protein deprivation on fetal and neonatal thyroid morphology in the rat.

Morphogenesis of the thyroid was compared in young of control and protein-deprived rats from day 17 of gestation through the first postpartum day. Examination of histological sections revealed a significant delay in follicle formation and a reduction in gland area, follicle number, colloid space and cell size in the thyroid tissue of fetal and neonatal pups of protein-deprived dams.

Animals↗
PubMed1977

Thyroid function in prenatally protein-deprived rats.

Thyroid function was examined in fetal and newborn young of dams fed diets containing 24% or 4% casein as the sole source of protein. Radioactive iodine uptake, as examined autoradiographically and by gamma counting, was significantly reduced in glands of progeny of deficient rats. Following injections of thyrotropin or thyrotropin releasing hormone, thyroid cells of newborn young of protein-deprived rats contained fewer colloid droplets than those of control pups. Circulating levels of triiodothyronine and thyroxine were significantly reduced in the plasma of newborn young of protein-deprived females as compared with controls.

Animals↗
PubMed1977

Carbohydrate absorption in the young of protein-deficient rats.

The absorption of 3-O-methylglucose (TMG) and of lactose has been studied in the young of female rats fed a protein-deficient diet during pregnancy. Postnatally, these young were suckled by stock diet-fed dams. Intestines of newborn, 4-day and 12-day old pups were infused in situ with 5% TMG or 3.5% lactose. The mean amount retained per enterocyte was measured as well as the mean amount absorbed from the lumen and transferred from the enterocyte. Absorption of lactose was reduced in the enterocytes of newborn prenatally protein-deprived (PPD) young but not postnatally, while TMG absorption was normal at birth and 12 days but reduced at 4 days. The amount of carbohydrates absorbed in total or per unit intestinal weight seemed to vary with changes in the number of absorptive cells. It is suggested that reduced absorption in PPD pups is primarily related to the smaller number of absorptive cells in these young. There is a greater increase in numbers of cells and in absorption per cell between birth and 12 days in PPD young than in controls, indicating that the effect on the intestine of prenatal protein deprived young is at least partially reversible.

Age Factors↗
PubMed1977

Effects of protein deficiency, pair-feeding, or diet supplementation on maternal, fetal and placental growth in rats.

The effects of feeding, throughout gestation, a diet deficient in protein, of pair-feeding, and of supplementing the deficient diet late in gestation on maternal body weight and weights of the products of conception were investigated in the rat. Protein deprivation resulted in net loss of maternal body weight, smaller and thinner placentas with decreased DNA content and placental labyrinth size, reduced uterine tissue weight, and smaller fetuses with retarded bone development. Pair-feeding caused a less severe reduction in maternal, uterine, placental, and fetal weights. Placentas from pair-fed dams had normal cell numbers with reduced cell size. Diet supplementation late in gestation resulted in increased net and total maternal body weight and uterine, placental, and fetal fetal weights, and an apparent partial recovery in fetal bone development. Placental cell size also increased significantly. The results suggest that placental and uterine development in protein-deficient dams is not the limiting factor in fetal development. Availability of protein may be the primary limiting factor, and energy deficit may play a secondary role.

Animals↗
PubMed1977

Early postnatal development of the intestine in progeny of protein-deprived rats.

Development of the small intestine was studied in newborn, and 4-, 8-, and 12-day-old young of rats fed diets, during gestation, containing 24 or 4% casein as the source of protein. Newborn prenatally protein-deprived rats had shorter, narrower intestines, reduced numbers of villi per unit length, shorter villi, and reduced numbers of absorptive cells and crypt cells. These differences had disappeared by the age of 12 days in adequately fed pups that had survived to that age.

Animals↗
PubMed1977

The effects of prenatal protein deprivation on thyrotroph development.

Maternal dietary protein restriction produced by feeding a diet containing 4% casein throughout gestation adversely affects body size and retards development of various organs in the progeny. For the most part, alterations are present in structural or functional entities which evolve during the last trimester of gestation. Fetal thyroid follicle formation and iodine concentrating capacity, which increase rapidly between the 17th gestational day and birth in pups of dams fed the control (24% casein) ration, are retarded in age-matched pups of protein-deficient females. The first immunoreactive thyrotrophs appear in the fetal pituitary on day 17 in both control and prenatally protein-deprived (PPD) young. The total number of thyrotrophs per pituitary was unaffected by maternal protein deficiency, except on day 21 when there were significantly more thyrotrophs per pituitary in fetal control rats. Although pituitary volume was significantly reduced in 18-, 19- and 21-day old fetal PPD rats, as compared with controls, pituitary volume:body weight ratios differed between young in the two dietary groups only on day 21, when the ratio was significantly higher in PPD as compared to control young. Maternal protein deprivation does not affect the morphological maturation of the thyrotrophs of the anterior pituitary of the fetal rat.

Animals↗
PubMed1976

Lipid absorption in the young of protein-deficient rats.

The effect of reduced protein in the diet during pregnancy on the subsequent absorption of triolein and of oleic acid which were infused into the intestine of the young was studied. Pregnant rats were fed diets containing either 24% or 4% casein as the sole source of protein. Control and prenatally protein-deprived (PPD) young were studied at birth before and after suckling, and at 4, 8, and 12 days. Both body weight and the weight and length of intestine were reduced in PPD young. Uptake of triolein from the lumen and retention in enterocytes increased on suckling in newborn control pups, but the amount transferred from or metabolized by the cells did not change. In suckled PPD young, transfer of triolein increased through the enterocyte as well. Unsuckled PPD pups had reduced absorption and retention per enterocyte, per g body weight, per cm gut, and in total. In intestines of control and PPD suckled newborn and postnatal pups, absorption per cell did not differ. Blood lipid levels were increased markedly between 0 and 14 days and tended to decrease to newborn levels by 12 days in both diet groups. Oleic acid absorption in newborn and 12-day PPD pups were reduced in total, per g body weight and per cm of gut. The individual enterocytes were shown to be equally capable of absorption and transfer of triolein and oleic acid. Differences in absorption are related primarily to the numbers of absorptive cells.

Aging↗